Stomata, the pores formed by a pair of guard cells, are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Guard cell movement is regulated by a com...Stomata, the pores formed by a pair of guard cells, are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Guard cell movement is regulated by a combination of environmental factors, including water status, light, CO2 levels and pathogen attack, as well as endogenous signals, such as abscisic acid and apoplastic reactive oxygen species （ROS）. Under abiotic and biotic stress conditions, extracellular ROS are mainly produced by plasma membrane-localized NADPH oxidases, whereas intracellular ROS are produced in multiple organelles. These ROS form a sophisticated cellular signaling network, with the accumulation of apoplastic ROS an early hallmark of stomatal movement. Here, we review recent progress in understanding the molecular mechanisms of the ROS signaling network, primarily during drought stress and pathogen attack. We summarize the roles of apoplastic ROS in regulating stomatal movement, ABA and CO2 signaling, and immunity responses. Finally, we discuss ROS accumulation and communication between organelles and cells. This information provides a conceptual framework for understanding how ROS signaling is integrated with various signaling pathways during plant responses to abiotic and biotic stress stimuli.展开更多
Transpiration element is included in the integrated stomatal conductance photosynthesis model by considering gaseous transfer processes, so the present model is capable to simulate the influence of boundary layer con...Transpiration element is included in the integrated stomatal conductance photosynthesis model by considering gaseous transfer processes, so the present model is capable to simulate the influence of boundary layer conductance. Leuning in his revised Ball's model replaced relative humidity with VPD s (the vapor pressure deficit from stomatal pore to leaf surface) and thereby made the relation with transpiration more straightforward, and made it possible for the regulation of transpiration and the influence of boundary layer conductance to be integrated into the combined model. If the differences in water vapor and CO 2 concentration between leaf and ambient air are considered, VPD s , the evaporative demand, is influenced by stomatal and boundary layer conductance. The physiological responses of photosynthesis, transpiration, and stomatal function, and the changes of intercellular CO 2 and water use efficiency to environmental factors, such as wind speed, photon flux density, leaf temperature and ambient CO 2, are analyzed. It is shown that if the boundary layer conductance drops to a level comparable with stomatal conductance, the results of simulation by the model presented here differ significantly from those by the previous model, and, in some cases, are more realistic than the latter.展开更多
Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductan...Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductance and stomatal limitation value tended to decline simultaneously, while the interoellularCO2 concentration was increased. According to the two criteria discriminating the stomatal limitation of Photosynthesis suggeSted by Fmrquhar and Sharkey, the seasonal changes in these parameters indicated that the decrease in Pn may not be due to stomatal factor. These studies proved that the relative contents of the large subunit of Rubisco and the photochemical activities correlated with the seasonal changes in the net photosyntheticrate, whieh may show that these two factors contribute primarily to the seasonal changeS in CO2 assimilation.展开更多
The stomatal pores of higher plants enable gaseous exchange into and out of leaves for photosynthesis and evaporation. Stomatal opening is induced by both blue and red lights. It is shown that blue light-induced stoma...The stomatal pores of higher plants enable gaseous exchange into and out of leaves for photosynthesis and evaporation. Stomatal opening is induced by both blue and red lights. It is shown that blue light-induced stomatal opening is mediated by the blue light receptor phototropins （PHOT1 and PHOT2） and cryptochromes （CRY1 and CRY2）. However, whether phytochrome B （phyB） is involved in red light regulation of stomatal opening remains largely unclear. Here, we report a positive role for Arabidopsis （Arabidopsis thaliana） phyB in the regulation of red light-induced stomatal opening. The phyB mutant stomata displayed a reduced red light response, whereas stomata of the phyB-overexpressing plants displayed a hypersensitive response to red light. In addition, stomata of the cry1 cry2 phyB, photl phot2 phyB, and cry1 phyA phyB triple mutant plants showed more reduced light response than those of the single or double mutant plants under white light, implying that phyB acts in concert with phyA, CRY, and PHOT in light regulation of stomatal opening. Stomata of phyB cop1 mutant opened less wide than those of the cop1 mutant, and stomata of the pif3 pif4 mutant opened wider than those of the wild-type, indicating that COP1, together with the PIFs （phytochrome interacting factors）, may act downstream of PHYB in regulating stomatal opening. Furthermore, quantitative RT-PCR analysis showed that the expression of MYB60 was reduced in the cry1 cry2 and phyA phyB mutants under blue and red lights, respectively, but induced in the CRY1- and phyB-overexpressing plants. These results demonstrate that phyB and CRY might regulate stomatal opening, at least in part, by regulating MYB60 expression.展开更多
A better theoretical and practical understanding of the linkage between paleo-CO2 and climate during geological history is important to enhance the sustainable development of modern human society. Development in plant...A better theoretical and practical understanding of the linkage between paleo-CO2 and climate during geological history is important to enhance the sustainable development of modern human society. Development in plant physiology since the 1980s has led to the realization that fossil plants can serve as a proxy for paleoatmosphere and paleobiosphere. As a relict gymnosperm with evolutionary stasis, Ginkgo is well suited for paleoenvironmental reconstruction. This paper analyzes fossil Ginkgo species from integrated strata in the north of China using anatomic data of plant physiology. Using stomatal parameters, a trend for the paleo-CO2 level during the Early-Middle Jurassic and the Early Cretaceous was obtained, which is consistent with the estimates by GEOCARB. The trend is also similar to that of Mean Global Surface Temperature in geological time. Compared with three other atmospheric CO2 concentration parameters, the trend of paleo-CO2 level based on the stomatal parameter of the fossil Ginkgo specimens from three contiguous strata is more exact.展开更多
In wheat, the ear is one of the main photosynthetic contributors to grain filling under drought stress conditions. In order to determine the relationship between stomatal characteristics and plant drought resistance, ...In wheat, the ear is one of the main photosynthetic contributors to grain filling under drought stress conditions. In order to determine the relationship between stomatal characteristics and plant drought resistance, photosynthetic and stomatal characteristics and water use efficiency(WUE) were studied in two wheat cultivars: the drought-resistant cultivar ‘Changhan 58' and the drought-sensitive cultivar ‘Xinong 9871'. Plants of both cultivars were grown in pot conditions under well-watered(WW) and water-stressed(WS) conditions. In both water regimes,‘Changhan 58' showed a significantly higher ear photosynthetic rate with a lower rate of variation and a significantly higher percentage variation of transpiration compared to control plants at the heading stage under WS conditions than did ‘Xinong 9871' plants. Moreover,‘Changhan 58' showed lower stomatal density(SD) and higher stomatal area per unit organ area(A) under both water conditions. Water stress decreased SD, A, and stomatal width(SW), and increased stomatal length in flag leaves(upper and lower surfaces) and ear organs(awn, glume,lemma, and palea), with the changes more pronounced in ear organs than in flag leaves.Instantaneous WUE increased slightly, while integral WUE improved significantly in both cultivars. Integral WUE was higher in ‘Changhan 58', and increased by a greater amount, than in‘Xinong 9871'. These results suggest that drought resistance in ‘Changhan 58' is regulated by stomatal characteristics through a decrease in transpiration rate in order to improve integral WUE and photosynthetic performance, and through sustaining a higher ear photosynthetic rate, therefore enhancing overall drought-resistance.展开更多
A greenhouse experlment was performed In order to Investigate the effects of dlfferent levels of water stress on leaf water potentlal （ψw）, stomatal resistance （rs）, protein content and chlorophyll （Chl） conten...A greenhouse experlment was performed In order to Investigate the effects of dlfferent levels of water stress on leaf water potentlal （ψw）, stomatal resistance （rs）, protein content and chlorophyll （Chl） content of tomato plants （Lycoperslcon esculentum Mill. cv. Nlkita）. Water stress was Induced by addlng polyethylene glycol （PEG 6 000） to the nutrlent solution to reduce the osmotlc potential （ψs）. We Investlgated the behavlor of antl-oxldant enzymes, such as catalase （CAT） and superoxide dlsmutase （SOD）, durlng the development of water stress. Moderate and severe water stress （i.e. ψs= -0.51 and -1.22 MPa, respectlvely） caused a decrease In ψw for all treated （water-stressed） plants compared with control plants, wlth the reductlon belng more pronounced for severely stressed plants. In addltion, rs was slgnlflcantly affected by the Induced water stress and a decrease in leaf soluble protelns and Chl content was observed. Whereas CAT actlvlty remained constant, SOD actlvlty was increased in water-stressed plants compared wlth unstressed plants. These results Indicate the possible role of SOD as an anti-oxidant protector system for plants under water stress condltlons. Moreover, It suggests the possibllity of using this enzyme as an addltional screening crlterlon for detecting water stress in plants.展开更多
Under natural conditions, plants constantly encounter various biotic and abiotic factors, which can potentially restrict plant growth and development and even limit crop productivity. Among various abiotic factors aff...Under natural conditions, plants constantly encounter various biotic and abiotic factors, which can potentially restrict plant growth and development and even limit crop productivity. Among various abiotic factors affecting plant photosynthesis, light serves as an important factor that drives carbon metabolism in plants and supports life on earth. The two components of light(light quality and light intensity) greatly affect plant photosynthesis and other plant's morphological, physiological and biochemical parameters. The response of plants to different spectral radiations and intensities differs in various species and also depends on growing conditions. To date, much research has been conducted regarding how different spectral radiations of varying intensity can affect plant growth and development. This review is an effort to briefly summarize the available information on the effects of light components on various plant parameters such as stem and leaf morphology and anatomy, stomatal development, photosynthetic apparatus, pigment composition, reactive oxygen species(ROS) production, antioxidants, and hormone production.展开更多
For finding valuable systematic characters, leaf epidermis of 77 taxa, representing 12 sections of the genus Clematis and three related genera in the Ranunculaceae, were examined mainly by means of light microscop...For finding valuable systematic characters, leaf epidermis of 77 taxa, representing 12 sections of the genus Clematis and three related genera in the Ranunculaceae, were examined mainly by means of light microscopy (LM), and partially by scanning electron microscopy (SEM). It was shown that the leaf epidermal cells were usually irregular or polygonal in shape. The patterns of anticlinal walls were straight, arched or undulate. The stomatal apparatus is anomocytic and exists in abaxial epidermis of all species, and in the adaxial epidermis of some species. Under SEM observation, the leaf epidermis was often striated, seldom nearly smooth, and often with flakes attached. Evidence from leaf epidermis serves as a criterion for distinguishing the subsections in sect. Meclatis (Spach) Tamura and in sect. Fruticella Tamura. The results also support that there are several separate evolutionary processes in the genus Clematis .展开更多
Stomatal conductance was found to change from steady-state to a slate of oscillations during daytime when vapour pressure deficit (VPD) increased to a value of 1 kPa in Glycyrrhiza inflata Batalin grown under the cond...Stomatal conductance was found to change from steady-state to a slate of oscillations during daytime when vapour pressure deficit (VPD) increased to a value of 1 kPa in Glycyrrhiza inflata Batalin grown under the conditions of arid desert in north-west China. The injected metabolic inhibitors (NaN3 or carbonyl cyanide-m-chlorophenyl-hydrazone (CCCP)) slightly reduced the stomatal conductance but did not significantly decrease the intensity of stomatal oscillations (amplitude/average). The oscillation intensity was found to he significantly correlated with VPD and root resistance, but not with the respiration rate. There might exist a minimum threshold of VPD (0.8 kPa) and root resistance (1/4 relative value) that induced stomatal oscillations. These results suggested that stomatal oscillations induced by atmospheric drought stress and root resistance were mainly a type of hydropassive movement.展开更多
Stomatal movements are critical in regulating gas exchange for photosynthesis and water balance between plant tissues and the atmosphere. The plant hormone abscisic acid （ABA） plays key roles in regulating stomatal ...Stomatal movements are critical in regulating gas exchange for photosynthesis and water balance between plant tissues and the atmosphere. The plant hormone abscisic acid （ABA） plays key roles in regulating stomatal closure under various abiotic stresses. In this study, we revealed a novel role of BAKI in guard cell ABA signaling. We found that the brassinosteroid （BR） signaling mutant bakl lost more water than wild- type plants and showed ABA insensitivity in stomatal closure. ABA-induced OST1 expression and reactive oxygen species （ROS） production were also impaired in bakl. Unlike direct treatment with H202, overex-pression of OST1 did not completely rescue the insensitivity of bakl to ABA. We demonstrated that BAK1 forms a complex with OST1 near the plasma membrane and that the BAKI/OST1 complex is increased in response to ABA in planta. Brassinolide, the most active BR, exerted a negative effect on ABA-induced formation of the BAK1/OST1 complex and OST1 expression. Moreover, we found that BAK1 and ABI1 oppositely regulate OST1 phosphorylation in vitro, and that ABI1 interacts with BAK1 and inhibits the interaction of BAK1 and OST1. Taken together, our results suggest that BAK1 regulates ABA-induced stomatal closure in guard cells.展开更多
The relationship between carbon assimilation and high-level expression of the maize PEPC in PEPC transgenic rice was studied by comparison to that in the untransformed rice, japonica kitaake. Stomatal conductance and ...The relationship between carbon assimilation and high-level expression of the maize PEPC in PEPC transgenic rice was studied by comparison to that in the untransformed rice, japonica kitaake. Stomatal conductance and photosynthetic rates in PEPC transgenic rice were higher than those of untransformed rice, but the increase of stomatal conductance had no statistical correlation with that of photosynthetic rate. Under high levels of light intensity, the protein contents of PEPC and CA were increased significantly. Therefore the photosynthetic capacity was increased greatly (50%) with atmospheric CO2 supply. While CO2 release in leaf was reduced and the compensation point was lowered correspondingly under CO2 free conditions. Treatment of the rice with the PEPC-specific inhibitor DCDP showed that overexpression of PEPC and enhancement of carbon assimilation were related to the stability of Fv/Fm. Labeling with 14CO2 for 20 s showed more 14C was distributed to C4 primary photosynthate asperate in PEPC transgenic rice, suggesting that there exists a limiting C4 photosynthetic mechanism in leaves. These results suggest that the primitive CO2 concentrating mechanism found in rice could be reproduced through metabolic engineering, and shed light on the physiological basis for transgenic breeding with high photosynthetic efficiency.展开更多
In recent years, adenosine tri-phosphate （ATP） has been reported to exist in apoplasts of plant cells as a signal molecule. Extracellular ATP （eATP） plays important roles in plant growth, development, and stress t...In recent years, adenosine tri-phosphate （ATP） has been reported to exist in apoplasts of plant cells as a signal molecule. Extracellular ATP （eATP） plays important roles in plant growth, development, and stress tolerance. Here, extra- cellular ATP was found to promote stomatal opening of Arabidopsis thaliana in light and darkness. ADP, GTP, and weakly hydrolyzable ATP analogs （ATPγS, Bz-ATP, and 2meATP） showed similar effects, whereas AMP and adenosine did not affect stomatal movement. Apyrase inhibited stomatal opening. ATP-promoted stomatal opening was blocked by an NADPH oxidase inhibitor （diphenylene iodonium） or deoxidizer （dithiothreitol）, and was impaired in null mutant of NADPH ox- idase （atrbohD/F）. Added ATP triggered ROS generation in guard cells via NADPH oxidase. ATP also induced Ca^2＋ influx and H ＋ efflux in guard cells. In atrbohD/F, ATP-induced ion flux was strongly suppressed. In null mutants of the heterotrimeric G protein α subunit, ATP-promoted stomatal opening, cytoplasmic ROS generation, Ca^2＋ influx, and ^H＋ efflux were all sup- pressed. These results indicated that eATP-promoted stomatal opening possibly involves the heterotrimeric G protein, ROS, cytosolic Ca^2＋, and plasma membrane H＋-ATPase.展开更多
The regulation of stomatal lineage cell development has been extensively investigated.However,a comprehensive characterization of this biological process based on single-cell transcriptome analysis has not yet been re...The regulation of stomatal lineage cell development has been extensively investigated.However,a comprehensive characterization of this biological process based on single-cell transcriptome analysis has not yet been reported.In this study,we performed RNA sequencing on 12844 individual cells from the cotyledons of 5-day-old Arabidopsis seedlings.We identified 11 cell clusters corresponding mostly to cells at specific stomatal developmental stages using a series of marker genes.Comparative analysis of genes with the highest variable expression among these cell clusters revealed transcriptional networks that regulate development from meristemoid mother cells to guard mother cells.Examination of the developmental dynamics of marker genes via pseudo-time analysis revealed potential interactions between these genes.Collectively,our study opens the door for understanding how the identified novel marker genes participate in the regulation of stomatal lineage cell development.展开更多
Hydrogen sulfide （H2S） is a newly-discovered signaling molecule in plants and has caused increasing attention in recent years, but its function in stomatal movement is unclear. In plants, H2S is synthesized via cyst...Hydrogen sulfide （H2S） is a newly-discovered signaling molecule in plants and has caused increasing attention in recent years, but its function in stomatal movement is unclear. In plants, H2S is synthesized via cysteine degradation catalyzed by D-/L-cysteine desulfhydrase （D-/L-CDes）. AtD-/L-CDes：：GUS transgenic Arabidopsis thaliana （L.） Heynh. plants were generated and used to investigate gene expression patterns, and results showed that AtD-/L-CDes can be expressed in guard cells. We also determined the subcellular localization of AtD-/L-CDes using transgenic plants of AtD-/L-CDes：：GFP, and the results showed that AtD-CDes and AtL-CDes are located in the chloroplast and in the cytoplasm, respectively. The transcript levels of AtD-CDes and AtL-CDes were affected by the chemicals that cause stomatal closure. Among these factors, ACC, a precursor of ethylene, has the most significant effect, which indicates that the H2S generated from D-/L-CDes may play an important role in ethylene-induced stomatal closure. Meanwhile, H2S synthetic inhibitors significantly inhibited ethylene-induced stomatal closure in Arabidopsis. Ethylene treatment caused an increase of H2S production and of AtD-/L-CDes activity in Arabidopsis leaves. AtD-/L-CDes over-expressing plants exhibited enhanced induction of stomatal closure compared to the wild-type after ethylene treatment; however, the effect was not observed in the Atd-cdes and Atl-cdes mutants. In conclusion, our results suggest that the D-/L-CDes-generated H2S is involved in the regulation of ethylene-induced stomatal closure in Arabidopsis thaliana.展开更多
The phytohormone abscisic acid(ABA)plays pivotal roles in triggering stomatal closure and facilitating adaptation of plants to drought stress.Hydrogen sulfide(H2S),a small signaling gas molecule,is involved in ABA-dep...The phytohormone abscisic acid(ABA)plays pivotal roles in triggering stomatal closure and facilitating adaptation of plants to drought stress.Hydrogen sulfide(H2S),a small signaling gas molecule,is involved in ABA-dependent stomatal closure.However,how H2S regulates ABA signaling remains largely unclear.Here,we show that ABA induces the production of H2S catalyzed by L-CYSTEINE DESULFHYDRASE1(DES1)in guard cells,and H2S in turn positively regulates ABA signaling through persulfidation of Open Stomata 1(OST1)/SNF1-RELATED PROTEIN KINASE2.6(SnRK2.6).Two cysteine(Cys)sites,Cys131 and Cys137,which are exposed on the surface of SnRK2.6 and close to the activation loop,were identified to be persulfidated,which promotes the activity of SnRK2.6 and its interaction with ABA response element-binding factor 2(ABF2),a transcription factor acting downstream of ABA signaling.When Cys131,Cys137,or both residues in SnRK2.6 were substituted with serine(S),H2S_induced SnRK2_6 activity and SnRK2.6-ABF2 interaction were partially(SnRK2.6c131s and SnRK2.6c137S)or completely(SnRK2.6c131sc137S)compromised.Introduction of SnRK2.6c131s,SnRK2.6c137S,or SnRK2.6c131sc137S into the ost1-3 mutant could not rescue the mutant phenotype:less sensitivity to ABA-and H2S-induced stomatal closure and Ca2+influx as well as increased water loss and decreased drought tolerance.Taken together,our study reveals a novel post-translational regulatory mechanism of ABA signaling whereby H2S persulfidates SnRK2.6 to promote ABA signaling and ABA-induced stomatal closure.展开更多
The study on the changes of stomatal sensitivity in relation to xylem ABA during periodical soil drying and the effect of leaf water status on the stomatal sensitivity has confirmed that xylem ABA concentration is a g...The study on the changes of stomatal sensitivity in relation to xylem ABA during periodical soil drying and the effect of leaf water status on the stomatal sensitivity has confirmed that xylem ABA concentration is a good indicator of soil water status around roots and the relation between xylem ABA concentration and predawn leaf water potential remained constant during the three consecutive soil drying cycles based on the slopes of the fitted lines. The sensitivity of stomata to xylem ABA increased substantially as the soil drying cycles progressed, and the xylem ABA concentration needed to cause a 50% decrease of stomatal conductance was as low as 550 nmol/L in the next two soil drying cycle, as compared with the 750 nmol/L ABA in the first cycle of soil drying. The results using the split_root system showed that leaf water deficit significantly enhanced the stomatal response to xylem ABA and the xylem ABA concentration needed to cause a 50% decrease in stomatal conductance was 2 to 4 times smaller in the whole_root_drying treatment than those in the semi_root_drying treatment. These results suggested that the sensitivity of stomata to xylem ABA concentration is not a fixed characteristic.展开更多
基金supported by the National Key Scientific Research Project(2011CB915400)supported by the National Natural Science Foundation of China(31730007)
文摘Stomata, the pores formed by a pair of guard cells, are the main gateways for water transpiration and photosynthetic CO2 exchange, as well as pathogen invasion in land plants. Guard cell movement is regulated by a combination of environmental factors, including water status, light, CO2 levels and pathogen attack, as well as endogenous signals, such as abscisic acid and apoplastic reactive oxygen species （ROS）. Under abiotic and biotic stress conditions, extracellular ROS are mainly produced by plasma membrane-localized NADPH oxidases, whereas intracellular ROS are produced in multiple organelles. These ROS form a sophisticated cellular signaling network, with the accumulation of apoplastic ROS an early hallmark of stomatal movement. Here, we review recent progress in understanding the molecular mechanisms of the ROS signaling network, primarily during drought stress and pathogen attack. We summarize the roles of apoplastic ROS in regulating stomatal movement, ABA and CO2 signaling, and immunity responses. Finally, we discuss ROS accumulation and communication between organelles and cells. This information provides a conceptual framework for understanding how ROS signaling is integrated with various signaling pathways during plant responses to abiotic and biotic stress stimuli.
文摘Transpiration element is included in the integrated stomatal conductance photosynthesis model by considering gaseous transfer processes, so the present model is capable to simulate the influence of boundary layer conductance. Leuning in his revised Ball's model replaced relative humidity with VPD s (the vapor pressure deficit from stomatal pore to leaf surface) and thereby made the relation with transpiration more straightforward, and made it possible for the regulation of transpiration and the influence of boundary layer conductance to be integrated into the combined model. If the differences in water vapor and CO 2 concentration between leaf and ambient air are considered, VPD s , the evaporative demand, is influenced by stomatal and boundary layer conductance. The physiological responses of photosynthesis, transpiration, and stomatal function, and the changes of intercellular CO 2 and water use efficiency to environmental factors, such as wind speed, photon flux density, leaf temperature and ambient CO 2, are analyzed. It is shown that if the boundary layer conductance drops to a level comparable with stomatal conductance, the results of simulation by the model presented here differ significantly from those by the previous model, and, in some cases, are more realistic than the latter.
文摘Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductance and stomatal limitation value tended to decline simultaneously, while the interoellularCO2 concentration was increased. According to the two criteria discriminating the stomatal limitation of Photosynthesis suggeSted by Fmrquhar and Sharkey, the seasonal changes in these parameters indicated that the decrease in Pn may not be due to stomatal factor. These studies proved that the relative contents of the large subunit of Rubisco and the photochemical activities correlated with the seasonal changes in the net photosyntheticrate, whieh may show that these two factors contribute primarily to the seasonal changeS in CO2 assimilation.
文摘The stomatal pores of higher plants enable gaseous exchange into and out of leaves for photosynthesis and evaporation. Stomatal opening is induced by both blue and red lights. It is shown that blue light-induced stomatal opening is mediated by the blue light receptor phototropins （PHOT1 and PHOT2） and cryptochromes （CRY1 and CRY2）. However, whether phytochrome B （phyB） is involved in red light regulation of stomatal opening remains largely unclear. Here, we report a positive role for Arabidopsis （Arabidopsis thaliana） phyB in the regulation of red light-induced stomatal opening. The phyB mutant stomata displayed a reduced red light response, whereas stomata of the phyB-overexpressing plants displayed a hypersensitive response to red light. In addition, stomata of the cry1 cry2 phyB, photl phot2 phyB, and cry1 phyA phyB triple mutant plants showed more reduced light response than those of the single or double mutant plants under white light, implying that phyB acts in concert with phyA, CRY, and PHOT in light regulation of stomatal opening. Stomata of phyB cop1 mutant opened less wide than those of the cop1 mutant, and stomata of the pif3 pif4 mutant opened wider than those of the wild-type, indicating that COP1, together with the PIFs （phytochrome interacting factors）, may act downstream of PHYB in regulating stomatal opening. Furthermore, quantitative RT-PCR analysis showed that the expression of MYB60 was reduced in the cry1 cry2 and phyA phyB mutants under blue and red lights, respectively, but induced in the CRY1- and phyB-overexpressing plants. These results demonstrate that phyB and CRY might regulate stomatal opening, at least in part, by regulating MYB60 expression.
基金supported by the National Basic Research Program of China(No.2006CB701400)the National Natural Science Foundation of China(No.40372012,40772012)the Foundation of the State Key Laboratory of Paleobiology and Stratigraphy,Nanjing Institute of Geology and Paleontology,Chinese Academy of Sciences(No.063101).
文摘A better theoretical and practical understanding of the linkage between paleo-CO2 and climate during geological history is important to enhance the sustainable development of modern human society. Development in plant physiology since the 1980s has led to the realization that fossil plants can serve as a proxy for paleoatmosphere and paleobiosphere. As a relict gymnosperm with evolutionary stasis, Ginkgo is well suited for paleoenvironmental reconstruction. This paper analyzes fossil Ginkgo species from integrated strata in the north of China using anatomic data of plant physiology. Using stomatal parameters, a trend for the paleo-CO2 level during the Early-Middle Jurassic and the Early Cretaceous was obtained, which is consistent with the estimates by GEOCARB. The trend is also similar to that of Mean Global Surface Temperature in geological time. Compared with three other atmospheric CO2 concentration parameters, the trend of paleo-CO2 level based on the stomatal parameter of the fossil Ginkgo specimens from three contiguous strata is more exact.
基金supported by the National Key Technology R&D Program of China (2015BAD22B01)the Plan 111 of the Ministry of Education (B12007)+1 种基金the National Natural Science Foundation of China (31500320)Special Funds of Scientific Research Programs of State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau (A314021403-C5)
文摘In wheat, the ear is one of the main photosynthetic contributors to grain filling under drought stress conditions. In order to determine the relationship between stomatal characteristics and plant drought resistance, photosynthetic and stomatal characteristics and water use efficiency(WUE) were studied in two wheat cultivars: the drought-resistant cultivar ‘Changhan 58' and the drought-sensitive cultivar ‘Xinong 9871'. Plants of both cultivars were grown in pot conditions under well-watered(WW) and water-stressed(WS) conditions. In both water regimes,‘Changhan 58' showed a significantly higher ear photosynthetic rate with a lower rate of variation and a significantly higher percentage variation of transpiration compared to control plants at the heading stage under WS conditions than did ‘Xinong 9871' plants. Moreover,‘Changhan 58' showed lower stomatal density(SD) and higher stomatal area per unit organ area(A) under both water conditions. Water stress decreased SD, A, and stomatal width(SW), and increased stomatal length in flag leaves(upper and lower surfaces) and ear organs(awn, glume,lemma, and palea), with the changes more pronounced in ear organs than in flag leaves.Instantaneous WUE increased slightly, while integral WUE improved significantly in both cultivars. Integral WUE was higher in ‘Changhan 58', and increased by a greater amount, than in‘Xinong 9871'. These results suggest that drought resistance in ‘Changhan 58' is regulated by stomatal characteristics through a decrease in transpiration rate in order to improve integral WUE and photosynthetic performance, and through sustaining a higher ear photosynthetic rate, therefore enhancing overall drought-resistance.
基金supported by the National Natural Science Foundation of China(30424813)Science Publication Foundation of the Chinese Academy of Sciences
文摘A greenhouse experlment was performed In order to Investigate the effects of dlfferent levels of water stress on leaf water potentlal （ψw）, stomatal resistance （rs）, protein content and chlorophyll （Chl） content of tomato plants （Lycoperslcon esculentum Mill. cv. Nlkita）. Water stress was Induced by addlng polyethylene glycol （PEG 6 000） to the nutrlent solution to reduce the osmotlc potential （ψs）. We Investlgated the behavlor of antl-oxldant enzymes, such as catalase （CAT） and superoxide dlsmutase （SOD）, durlng the development of water stress. Moderate and severe water stress （i.e. ψs= -0.51 and -1.22 MPa, respectlvely） caused a decrease In ψw for all treated （water-stressed） plants compared with control plants, wlth the reductlon belng more pronounced for severely stressed plants. In addltion, rs was slgnlflcantly affected by the Induced water stress and a decrease in leaf soluble protelns and Chl content was observed. Whereas CAT actlvlty remained constant, SOD actlvlty was increased in water-stressed plants compared wlth unstressed plants. These results Indicate the possible role of SOD as an anti-oxidant protector system for plants under water stress condltlons. Moreover, It suggests the possibllity of using this enzyme as an addltional screening crlterlon for detecting water stress in plants.
基金supported by the National Natural Science Foundation of China (31571615)the earmarked fund for China Agriculture Research System (CARS-04-PS19)。
文摘Under natural conditions, plants constantly encounter various biotic and abiotic factors, which can potentially restrict plant growth and development and even limit crop productivity. Among various abiotic factors affecting plant photosynthesis, light serves as an important factor that drives carbon metabolism in plants and supports life on earth. The two components of light(light quality and light intensity) greatly affect plant photosynthesis and other plant's morphological, physiological and biochemical parameters. The response of plants to different spectral radiations and intensities differs in various species and also depends on growing conditions. To date, much research has been conducted regarding how different spectral radiations of varying intensity can affect plant growth and development. This review is an effort to briefly summarize the available information on the effects of light components on various plant parameters such as stem and leaf morphology and anatomy, stomatal development, photosynthetic apparatus, pigment composition, reactive oxygen species(ROS) production, antioxidants, and hormone production.
文摘For finding valuable systematic characters, leaf epidermis of 77 taxa, representing 12 sections of the genus Clematis and three related genera in the Ranunculaceae, were examined mainly by means of light microscopy (LM), and partially by scanning electron microscopy (SEM). It was shown that the leaf epidermal cells were usually irregular or polygonal in shape. The patterns of anticlinal walls were straight, arched or undulate. The stomatal apparatus is anomocytic and exists in abaxial epidermis of all species, and in the adaxial epidermis of some species. Under SEM observation, the leaf epidermis was often striated, seldom nearly smooth, and often with flakes attached. Evidence from leaf epidermis serves as a criterion for distinguishing the subsections in sect. Meclatis (Spach) Tamura and in sect. Fruticella Tamura. The results also support that there are several separate evolutionary processes in the genus Clematis .
文摘Stomatal conductance was found to change from steady-state to a slate of oscillations during daytime when vapour pressure deficit (VPD) increased to a value of 1 kPa in Glycyrrhiza inflata Batalin grown under the conditions of arid desert in north-west China. The injected metabolic inhibitors (NaN3 or carbonyl cyanide-m-chlorophenyl-hydrazone (CCCP)) slightly reduced the stomatal conductance but did not significantly decrease the intensity of stomatal oscillations (amplitude/average). The oscillation intensity was found to he significantly correlated with VPD and root resistance, but not with the respiration rate. There might exist a minimum threshold of VPD (0.8 kPa) and root resistance (1/4 relative value) that induced stomatal oscillations. These results suggested that stomatal oscillations induced by atmospheric drought stress and root resistance were mainly a type of hydropassive movement.
文摘Stomatal movements are critical in regulating gas exchange for photosynthesis and water balance between plant tissues and the atmosphere. The plant hormone abscisic acid （ABA） plays key roles in regulating stomatal closure under various abiotic stresses. In this study, we revealed a novel role of BAKI in guard cell ABA signaling. We found that the brassinosteroid （BR） signaling mutant bakl lost more water than wild- type plants and showed ABA insensitivity in stomatal closure. ABA-induced OST1 expression and reactive oxygen species （ROS） production were also impaired in bakl. Unlike direct treatment with H202, overex-pression of OST1 did not completely rescue the insensitivity of bakl to ABA. We demonstrated that BAK1 forms a complex with OST1 near the plasma membrane and that the BAKI/OST1 complex is increased in response to ABA in planta. Brassinolide, the most active BR, exerted a negative effect on ABA-induced formation of the BAK1/OST1 complex and OST1 expression. Moreover, we found that BAK1 and ABI1 oppositely regulate OST1 phosphorylation in vitro, and that ABI1 interacts with BAK1 and inhibits the interaction of BAK1 and OST1. Taken together, our results suggest that BAK1 regulates ABA-induced stomatal closure in guard cells.
基金supported by the State Key Basic Research and Development Plan(G1998010100)in China.
文摘The relationship between carbon assimilation and high-level expression of the maize PEPC in PEPC transgenic rice was studied by comparison to that in the untransformed rice, japonica kitaake. Stomatal conductance and photosynthetic rates in PEPC transgenic rice were higher than those of untransformed rice, but the increase of stomatal conductance had no statistical correlation with that of photosynthetic rate. Under high levels of light intensity, the protein contents of PEPC and CA were increased significantly. Therefore the photosynthetic capacity was increased greatly (50%) with atmospheric CO2 supply. While CO2 release in leaf was reduced and the compensation point was lowered correspondingly under CO2 free conditions. Treatment of the rice with the PEPC-specific inhibitor DCDP showed that overexpression of PEPC and enhancement of carbon assimilation were related to the stability of Fv/Fm. Labeling with 14CO2 for 20 s showed more 14C was distributed to C4 primary photosynthate asperate in PEPC transgenic rice, suggesting that there exists a limiting C4 photosynthetic mechanism in leaves. These results suggest that the primitive CO2 concentrating mechanism found in rice could be reproduced through metabolic engineering, and shed light on the physiological basis for transgenic breeding with high photosynthetic efficiency.
基金This work was supported by the National Science Foundation of China，the Program for New Century Excellent Talents in University，the State Key Laboratory of Plant Cell and Chromosome Engineering，No conflict of interest declared
文摘In recent years, adenosine tri-phosphate （ATP） has been reported to exist in apoplasts of plant cells as a signal molecule. Extracellular ATP （eATP） plays important roles in plant growth, development, and stress tolerance. Here, extra- cellular ATP was found to promote stomatal opening of Arabidopsis thaliana in light and darkness. ADP, GTP, and weakly hydrolyzable ATP analogs （ATPγS, Bz-ATP, and 2meATP） showed similar effects, whereas AMP and adenosine did not affect stomatal movement. Apyrase inhibited stomatal opening. ATP-promoted stomatal opening was blocked by an NADPH oxidase inhibitor （diphenylene iodonium） or deoxidizer （dithiothreitol）, and was impaired in null mutant of NADPH ox- idase （atrbohD/F）. Added ATP triggered ROS generation in guard cells via NADPH oxidase. ATP also induced Ca^2＋ influx and H ＋ efflux in guard cells. In atrbohD/F, ATP-induced ion flux was strongly suppressed. In null mutants of the heterotrimeric G protein α subunit, ATP-promoted stomatal opening, cytoplasmic ROS generation, Ca^2＋ influx, and ^H＋ efflux were all sup- pressed. These results indicated that eATP-promoted stomatal opening possibly involves the heterotrimeric G protein, ROS, cytosolic Ca^2＋, and plasma membrane H＋-ATPase.
基金This research was supported by the National Natural Science Foundation of China(31670233)the Key Scientific and Technological Projects in Henan Province,China(192102110113).
文摘The regulation of stomatal lineage cell development has been extensively investigated.However,a comprehensive characterization of this biological process based on single-cell transcriptome analysis has not yet been reported.In this study,we performed RNA sequencing on 12844 individual cells from the cotyledons of 5-day-old Arabidopsis seedlings.We identified 11 cell clusters corresponding mostly to cells at specific stomatal developmental stages using a series of marker genes.Comparative analysis of genes with the highest variable expression among these cell clusters revealed transcriptional networks that regulate development from meristemoid mother cells to guard mother cells.Examination of the developmental dynamics of marker genes via pseudo-time analysis revealed potential interactions between these genes.Collectively,our study opens the door for understanding how the identified novel marker genes participate in the regulation of stomatal lineage cell development.
基金supported by the National Natural Science Foundation of China (30970228 and 31170237)the National Natural Science Foundation of Shandong Province of China (ZR2010CM024)the Foundation of The State Key Laboratory of Plant Physiology and Biochemistry(SKLPPBKF11001)
文摘Hydrogen sulfide （H2S） is a newly-discovered signaling molecule in plants and has caused increasing attention in recent years, but its function in stomatal movement is unclear. In plants, H2S is synthesized via cysteine degradation catalyzed by D-/L-cysteine desulfhydrase （D-/L-CDes）. AtD-/L-CDes：：GUS transgenic Arabidopsis thaliana （L.） Heynh. plants were generated and used to investigate gene expression patterns, and results showed that AtD-/L-CDes can be expressed in guard cells. We also determined the subcellular localization of AtD-/L-CDes using transgenic plants of AtD-/L-CDes：：GFP, and the results showed that AtD-CDes and AtL-CDes are located in the chloroplast and in the cytoplasm, respectively. The transcript levels of AtD-CDes and AtL-CDes were affected by the chemicals that cause stomatal closure. Among these factors, ACC, a precursor of ethylene, has the most significant effect, which indicates that the H2S generated from D-/L-CDes may play an important role in ethylene-induced stomatal closure. Meanwhile, H2S synthetic inhibitors significantly inhibited ethylene-induced stomatal closure in Arabidopsis. Ethylene treatment caused an increase of H2S production and of AtD-/L-CDes activity in Arabidopsis leaves. AtD-/L-CDes over-expressing plants exhibited enhanced induction of stomatal closure compared to the wild-type after ethylene treatment; however, the effect was not observed in the Atd-cdes and Atl-cdes mutants. In conclusion, our results suggest that the D-/L-CDes-generated H2S is involved in the regulation of ethylene-induced stomatal closure in Arabidopsis thaliana.
基金the National Natural Science Foundation of China(NSFC 31700445,31400246)Shaanxi Province Natural Science Foundation of China(2018JM3017,2018JQ3020)China Postdoctoral Science Foundation(2018M641022).
文摘The phytohormone abscisic acid(ABA)plays pivotal roles in triggering stomatal closure and facilitating adaptation of plants to drought stress.Hydrogen sulfide(H2S),a small signaling gas molecule,is involved in ABA-dependent stomatal closure.However,how H2S regulates ABA signaling remains largely unclear.Here,we show that ABA induces the production of H2S catalyzed by L-CYSTEINE DESULFHYDRASE1(DES1)in guard cells,and H2S in turn positively regulates ABA signaling through persulfidation of Open Stomata 1(OST1)/SNF1-RELATED PROTEIN KINASE2.6(SnRK2.6).Two cysteine(Cys)sites,Cys131 and Cys137,which are exposed on the surface of SnRK2.6 and close to the activation loop,were identified to be persulfidated,which promotes the activity of SnRK2.6 and its interaction with ABA response element-binding factor 2(ABF2),a transcription factor acting downstream of ABA signaling.When Cys131,Cys137,or both residues in SnRK2.6 were substituted with serine(S),H2S_induced SnRK2_6 activity and SnRK2.6-ABF2 interaction were partially(SnRK2.6c131s and SnRK2.6c137S)or completely(SnRK2.6c131sc137S)compromised.Introduction of SnRK2.6c131s,SnRK2.6c137S,or SnRK2.6c131sc137S into the ost1-3 mutant could not rescue the mutant phenotype:less sensitivity to ABA-and H2S-induced stomatal closure and Ca2+influx as well as increased water loss and decreased drought tolerance.Taken together,our study reveals a novel post-translational regulatory mechanism of ABA signaling whereby H2S persulfidates SnRK2.6 to promote ABA signaling and ABA-induced stomatal closure.
文摘The study on the changes of stomatal sensitivity in relation to xylem ABA during periodical soil drying and the effect of leaf water status on the stomatal sensitivity has confirmed that xylem ABA concentration is a good indicator of soil water status around roots and the relation between xylem ABA concentration and predawn leaf water potential remained constant during the three consecutive soil drying cycles based on the slopes of the fitted lines. The sensitivity of stomata to xylem ABA increased substantially as the soil drying cycles progressed, and the xylem ABA concentration needed to cause a 50% decrease of stomatal conductance was as low as 550 nmol/L in the next two soil drying cycle, as compared with the 750 nmol/L ABA in the first cycle of soil drying. The results using the split_root system showed that leaf water deficit significantly enhanced the stomatal response to xylem ABA and the xylem ABA concentration needed to cause a 50% decrease in stomatal conductance was 2 to 4 times smaller in the whole_root_drying treatment than those in the semi_root_drying treatment. These results suggested that the sensitivity of stomata to xylem ABA concentration is not a fixed characteristic.
