The levels of endogenous plant hormones regulate floret development and degeneration, and thus grain set in flower crops. This study was undertaken to characterize the changes of endogenous hormone levels during flor...The levels of endogenous plant hormones regulate floret development and degeneration, and thus grain set in flower crops. This study was undertaken to characterize the changes of endogenous hormone levels during floret development in three wheat ( Triticum aestivum L.) genotypes: “97J1' with the highest grain set and fertile florets per spike, “H8679' with the lowest grain set and fertile florets per spike, and a medium, “YM158'. The results showed that the peak level of ABA appeared between stamen and pistil differentiation and antherlobe formation of floret development, and the timing delayed with the size of spike (earliest in “H8679” and latest in “97J1”). From antherlobe formation to meiosis, the levels of ABA and GA 1+3 decreased sharply in the ears of “97J1”, while in the ears of “H8679” there was only a slight decrease in ABA, and even an increase in GA 1+3 . The ratio of isopentenyladenosine (iPA)/ABA and IAA/ABA in the ears of “97J1” increased sharply from antherlobe formation to meiosis, but changed only slightly in the ears of “H8679”. At antherlobe formation, IAA and GA 1+3 levels were higher in the ears of “97J1”, but lower in the ears of “H8679” than in the leaves. At meiosis, ABA, GA 1+3 and IAA levels in the “97J1” ears were much lower than in the leaves, but similar in “H8679”. These results indicated that the sharp decreases of ABA and GA 1+3 in ears from antherlobe formation to meiosis and the lowest maintenance at meiosis may be favorable for development of fertile florets and enhancement of grain set in wheat.展开更多
Nitrogen(N)fertilization is critical for spike and floret development,which affects the number of fertile florets per spike(NFFs).However,the physiological regulation of the floret development process by N fertilizati...Nitrogen(N)fertilization is critical for spike and floret development,which affects the number of fertile florets per spike(NFFs).However,the physiological regulation of the floret development process by N fertilization is largely unknown.A high temporal-resolution investigation of floret primordia number and morphology,dry matter,and N availability was conducted under three N fertilization levels:0(N0),120(N1)and 240(N2)kg ha^(−1).Interestingly,fertile florets at anthesis stage were determined by those floret primordia with meiotic ability at booting stage:meiotic ability was a threshold that predicted whether a floret primordium became fertile or abortive florets.Because the developmental rate of the 4th floret primordium in the central spikelet was accelerated and then they acquired meiotic ability,the NFFs increased gradually as N application increased,but the increase range decreased under N2.There were no differences in spike N concentration among treatments,but leaf N concentration was increased in the N1 and N2 treatments.Correspondingly,dry matter accumulation and N content of the leaf and spike in the N1 and N2 treatments was increased as compared to N0.Clearly,optimal N fertilization increased leaf N availability and transport of assimilates to spikes,and allowed more floret primordia to acquire meiotic ability and become fertile florets,finally increasing NFFs.There was no difference in leaf N concentration between N1 and N2 treatment,whereas soil N concentration at 0–60 cm soil layers was higher in N2 than in N1 treatment,implying that there was still some N fertilization that remained unused.Therefore,improving the leaf’s ability to further use N fertilizer is vital for greater NFFs.展开更多
A double mutant with streaked leaf and abnormal floret was found and temporarily named streaked leaf and floral organ number mutant （st-fon）. For this mutant, besides white streak appeared on culm, leaves and panicl...A double mutant with streaked leaf and abnormal floret was found and temporarily named streaked leaf and floral organ number mutant （st-fon）. For this mutant, besides white streak appeared on culm, leaves and panicles, the number of floral organs increased and florets cracked. The extreme phenotype was that several small florets grew from one floret or branch rachis in small florets extended and developed into panicles. By using transmission electron microscope to observe the ultrastructure of white histocytes of leaves at the seedling stage, the white tissues which showed abnormal plastids, lamellas and thylakoids could not develop into normal chloroplast, and the development of chloroplast was blocked at the early growth stage of plastid. Scanning electron microscope and paraffin section were also used to observe the development of floral organs, and the results indicated that the development of floral meristem was out of order and unlimited, whereas in the twisty leaves, vascular bundle sheath cells grew excessively, or some bubbly cells increased. Genetic analyses carried out by means of cross and backcross with four normal-leaf-color materials revealed that the mutant is of cytoplasm inheritance.展开更多
Promoting more floret primordia within a spike to acquire fertile potential during the differentiation and pre-dimorphism phases is critical for increasing the number of fertile florets per spike(NFFs).However,it is y...Promoting more floret primordia within a spike to acquire fertile potential during the differentiation and pre-dimorphism phases is critical for increasing the number of fertile florets per spike(NFFs).However,it is yet unknown the physiological mechanism regulating the complex and dynamic process.This study aimed to clarify how intra-spike hormones,pigments,and assimilates coordinate with each other to regulate spike morphology and then floret primordia development.A two-year field experiment was conducted with two winter wheat genotypes:N50(big-spike with greater NFFs)and SM22(mediumspike with fewer NFFs).We monitored high temporal and spatial-resolution changes in the number and morphology of floret primordia within a spike,as well as in intra-spike hormones,pigments,and assimilates.Our results revealed that the big-spike genotype had more NFFs than the medium-spike genotype,not only because they had more spikelets,but also because they had greater NFFs mainly at central spikelets.More floret primordia at central spikelets had sufficient time to develop and acquire fertile potential during the differentiation phase(167-176 d after sowing,DAS)and the pre-dimorphism phase(179 DAS)for the big-spike genotype than the medium-spike genotype.Floret primordia with fertile morphology during the pre-dimorphism phase always developed into fertile florets during the dimorphism phase.Those early-developed floret primordia most proximal and intermediate to the rachis in the big-spike genotype developed faster than the medium-spike genotype.Correspondingly,the spike dry matter and pigments(chlorophyll a,chlorophyll b,carotene,and carotenoids)content during 170-182 DAS,auxin(IAA)and cytokinin(CTK)content on 167 DAS were significantly higher in the big-spike genotype than in the medium-spike genotype,while jasmonic acid(JA)content was significantly lower in the big-spike genotype compared to the medium-spike genotype during 167-182 DAS.Since the significant differences in intra-spike hormone content of the two genotypes appear展开更多
Transient heatwaves occurring more frequently as the climate warms,yet their impacts on crop yield are severely underestimated and even overlooked.Heatwaves lasting only a few days or even hours during sensitive stage...Transient heatwaves occurring more frequently as the climate warms,yet their impacts on crop yield are severely underestimated and even overlooked.Heatwaves lasting only a few days or even hours during sensitive stages,such as microgametogenesis and flowering,can significantly reduce crop yield by disrupting plant reproduction.Recent advances in multi-omics and GWAS analysis have shed light on the specific organs(e.g.,pollen,lodicule,style),key metabolic pathways(sugar and reactive oxygen species metabolism,Ca2+homeostasis),and essential genes that are involved in crop responses to transient heatwaves during sensitive stages.This review therefore places particular emphasis on heat-sensitive stages,with pollen development,floret opening,pollination,and fertilization as the central narrative thread.The multifaceted effects of transient heatwaves and their molecular basis are systematically reviewed,with a focus on key structures such as the lodicule and tapetum.A number of heat-tolerance genes associated with these processes have been identified in major crops like maize and rice.The mechanisms and key heat-tolerance genes shared among different stages may facilitate the more precise improvement of heat-tolerant crops.展开更多
The Q gene in common wheat encodes an APETALA2(AP2) transcription factor that causes the free threshing attribute. Wheat spikelets bearing several florets are subtended by a pair of soft glumes that allow free liberat...The Q gene in common wheat encodes an APETALA2(AP2) transcription factor that causes the free threshing attribute. Wheat spikelets bearing several florets are subtended by a pair of soft glumes that allow free liberation of seeds. In wild species, the glumes are tough and rigid,making threshing difficult. However, the nature of these "soft glumes", caused by the domestication allele Q is not clear. Here, we found that over expression of Q in common wheat leads to homeotic florets at glume positions. We provide phenotypic, microscopy, and marker genes evidence to demonstrate that the soft glumes of common wheat are in fact lemma-like organs, or so-called sterile-lemmas. By comparing the structures subtending spikelets in wheat and other crops such as rice and maize, we found that AP2 genes may play conserved functions in grasses by manipulating vestigial structures, such as floret-derived soft glumes in wheat and empty glumes in rice. Conversion of these seemingly vegetative organs to reproductive organs may be useful in yield improvement of crop species.展开更多
The study was carried out on the effect of nitrogen application in different wheat growth stage on the floret development, the photosynthetic rate, the yield and its components of winter wheat. The result indicated th...The study was carried out on the effect of nitrogen application in different wheat growth stage on the floret development, the photosynthetic rate, the yield and its components of winter wheat. The result indicated that nitrogen application in the pistil-stamen primordium formation stage and the tetrad formation stage of wheat growth prolonged the duration of floret development, promoted the balance growth of floret and reduced the floret decadence number, thus increased the grain number per spike. Nitrogen application in the middle and in the late stages of wheat development increased the photosynthetic ability of the plant leaves in the later stage, and also lengthened the peak of grain filling stage, thus enhanced the grain weight and yield of wheat significantly.展开更多
文摘The levels of endogenous plant hormones regulate floret development and degeneration, and thus grain set in flower crops. This study was undertaken to characterize the changes of endogenous hormone levels during floret development in three wheat ( Triticum aestivum L.) genotypes: “97J1' with the highest grain set and fertile florets per spike, “H8679' with the lowest grain set and fertile florets per spike, and a medium, “YM158'. The results showed that the peak level of ABA appeared between stamen and pistil differentiation and antherlobe formation of floret development, and the timing delayed with the size of spike (earliest in “H8679” and latest in “97J1”). From antherlobe formation to meiosis, the levels of ABA and GA 1+3 decreased sharply in the ears of “97J1”, while in the ears of “H8679” there was only a slight decrease in ABA, and even an increase in GA 1+3 . The ratio of isopentenyladenosine (iPA)/ABA and IAA/ABA in the ears of “97J1” increased sharply from antherlobe formation to meiosis, but changed only slightly in the ears of “H8679”. At antherlobe formation, IAA and GA 1+3 levels were higher in the ears of “97J1”, but lower in the ears of “H8679” than in the leaves. At meiosis, ABA, GA 1+3 and IAA levels in the “97J1” ears were much lower than in the leaves, but similar in “H8679”. These results indicated that the sharp decreases of ABA and GA 1+3 in ears from antherlobe formation to meiosis and the lowest maintenance at meiosis may be favorable for development of fertile florets and enhancement of grain set in wheat.
基金This study was supported by the National Key Research and Development Program of China(2022YFD1900703,2022YFD2300802)the Earmarked Fund for CARS(CARS-3)+1 种基金the National Natural Science Foundation of China(31871563)China Postdoctoral Science Foundation(2022M723437).
文摘Nitrogen(N)fertilization is critical for spike and floret development,which affects the number of fertile florets per spike(NFFs).However,the physiological regulation of the floret development process by N fertilization is largely unknown.A high temporal-resolution investigation of floret primordia number and morphology,dry matter,and N availability was conducted under three N fertilization levels:0(N0),120(N1)and 240(N2)kg ha^(−1).Interestingly,fertile florets at anthesis stage were determined by those floret primordia with meiotic ability at booting stage:meiotic ability was a threshold that predicted whether a floret primordium became fertile or abortive florets.Because the developmental rate of the 4th floret primordium in the central spikelet was accelerated and then they acquired meiotic ability,the NFFs increased gradually as N application increased,but the increase range decreased under N2.There were no differences in spike N concentration among treatments,but leaf N concentration was increased in the N1 and N2 treatments.Correspondingly,dry matter accumulation and N content of the leaf and spike in the N1 and N2 treatments was increased as compared to N0.Clearly,optimal N fertilization increased leaf N availability and transport of assimilates to spikes,and allowed more floret primordia to acquire meiotic ability and become fertile florets,finally increasing NFFs.There was no difference in leaf N concentration between N1 and N2 treatment,whereas soil N concentration at 0–60 cm soil layers was higher in N2 than in N1 treatment,implying that there was still some N fertilization that remained unused.Therefore,improving the leaf’s ability to further use N fertilizer is vital for greater NFFs.
基金supported by the Foundation Program,Innovative Team Development Plan of the Ministry of Education,China(Grant No.IRT0453)the Financial Gene Engineering Excellent Article Foundation Program of Sichuan Province,China(Grant No.2011LWJJ-005)
文摘A double mutant with streaked leaf and abnormal floret was found and temporarily named streaked leaf and floral organ number mutant （st-fon）. For this mutant, besides white streak appeared on culm, leaves and panicles, the number of floral organs increased and florets cracked. The extreme phenotype was that several small florets grew from one floret or branch rachis in small florets extended and developed into panicles. By using transmission electron microscope to observe the ultrastructure of white histocytes of leaves at the seedling stage, the white tissues which showed abnormal plastids, lamellas and thylakoids could not develop into normal chloroplast, and the development of chloroplast was blocked at the early growth stage of plastid. Scanning electron microscope and paraffin section were also used to observe the development of floral organs, and the results indicated that the development of floral meristem was out of order and unlimited, whereas in the twisty leaves, vascular bundle sheath cells grew excessively, or some bubbly cells increased. Genetic analyses carried out by means of cross and backcross with four normal-leaf-color materials revealed that the mutant is of cytoplasm inheritance.
基金funded by the Scientific and Technological Innovation Team Project of Seed Industry for Saline-alkali Tolerant Crop in Hebei Province(23327501D)the National Key Research and Development Program of China(2022YFD2300802,2022YFD1900703)the China Agriculture Research System(CARS-3).
文摘Promoting more floret primordia within a spike to acquire fertile potential during the differentiation and pre-dimorphism phases is critical for increasing the number of fertile florets per spike(NFFs).However,it is yet unknown the physiological mechanism regulating the complex and dynamic process.This study aimed to clarify how intra-spike hormones,pigments,and assimilates coordinate with each other to regulate spike morphology and then floret primordia development.A two-year field experiment was conducted with two winter wheat genotypes:N50(big-spike with greater NFFs)and SM22(mediumspike with fewer NFFs).We monitored high temporal and spatial-resolution changes in the number and morphology of floret primordia within a spike,as well as in intra-spike hormones,pigments,and assimilates.Our results revealed that the big-spike genotype had more NFFs than the medium-spike genotype,not only because they had more spikelets,but also because they had greater NFFs mainly at central spikelets.More floret primordia at central spikelets had sufficient time to develop and acquire fertile potential during the differentiation phase(167-176 d after sowing,DAS)and the pre-dimorphism phase(179 DAS)for the big-spike genotype than the medium-spike genotype.Floret primordia with fertile morphology during the pre-dimorphism phase always developed into fertile florets during the dimorphism phase.Those early-developed floret primordia most proximal and intermediate to the rachis in the big-spike genotype developed faster than the medium-spike genotype.Correspondingly,the spike dry matter and pigments(chlorophyll a,chlorophyll b,carotene,and carotenoids)content during 170-182 DAS,auxin(IAA)and cytokinin(CTK)content on 167 DAS were significantly higher in the big-spike genotype than in the medium-spike genotype,while jasmonic acid(JA)content was significantly lower in the big-spike genotype compared to the medium-spike genotype during 167-182 DAS.Since the significant differences in intra-spike hormone content of the two genotypes appear
基金supported by grants from the National Key R&D Program of China(2023YFD2303304)the National Science Foundation of China(32272214)+1 种基金the 2115 Talent Development Program of China Agricultural University,the Chinese Universities Scientific Fund(2024TC062)the Pinduoduo-China Agricultural University Research Fund(PC2023B02006).
文摘Transient heatwaves occurring more frequently as the climate warms,yet their impacts on crop yield are severely underestimated and even overlooked.Heatwaves lasting only a few days or even hours during sensitive stages,such as microgametogenesis and flowering,can significantly reduce crop yield by disrupting plant reproduction.Recent advances in multi-omics and GWAS analysis have shed light on the specific organs(e.g.,pollen,lodicule,style),key metabolic pathways(sugar and reactive oxygen species metabolism,Ca2+homeostasis),and essential genes that are involved in crop responses to transient heatwaves during sensitive stages.This review therefore places particular emphasis on heat-sensitive stages,with pollen development,floret opening,pollination,and fertilization as the central narrative thread.The multifaceted effects of transient heatwaves and their molecular basis are systematically reviewed,with a focus on key structures such as the lodicule and tapetum.A number of heat-tolerance genes associated with these processes have been identified in major crops like maize and rice.The mechanisms and key heat-tolerance genes shared among different stages may facilitate the more precise improvement of heat-tolerant crops.
基金supported by the National Key Program for Transgenic Crop Cultivation (2016ZX09001-001)The CAAS Agricultural Science and Technology Innovation Program Cooperation and Innovation Mission (CAAS-XTCX2016)
文摘The Q gene in common wheat encodes an APETALA2(AP2) transcription factor that causes the free threshing attribute. Wheat spikelets bearing several florets are subtended by a pair of soft glumes that allow free liberation of seeds. In wild species, the glumes are tough and rigid,making threshing difficult. However, the nature of these "soft glumes", caused by the domestication allele Q is not clear. Here, we found that over expression of Q in common wheat leads to homeotic florets at glume positions. We provide phenotypic, microscopy, and marker genes evidence to demonstrate that the soft glumes of common wheat are in fact lemma-like organs, or so-called sterile-lemmas. By comparing the structures subtending spikelets in wheat and other crops such as rice and maize, we found that AP2 genes may play conserved functions in grasses by manipulating vestigial structures, such as floret-derived soft glumes in wheat and empty glumes in rice. Conversion of these seemingly vegetative organs to reproductive organs may be useful in yield improvement of crop species.
文摘The study was carried out on the effect of nitrogen application in different wheat growth stage on the floret development, the photosynthetic rate, the yield and its components of winter wheat. The result indicated that nitrogen application in the pistil-stamen primordium formation stage and the tetrad formation stage of wheat growth prolonged the duration of floret development, promoted the balance growth of floret and reduced the floret decadence number, thus increased the grain number per spike. Nitrogen application in the middle and in the late stages of wheat development increased the photosynthetic ability of the plant leaves in the later stage, and also lengthened the peak of grain filling stage, thus enhanced the grain weight and yield of wheat significantly.
