The majority of rice(Oryza sativa L.) produced in the southern USA is drill-seeded and grown under upland-like conditions because permanent flooding is established after the four-leaf stage. Therefore, rice during the...The majority of rice(Oryza sativa L.) produced in the southern USA is drill-seeded and grown under upland-like conditions because permanent flooding is established after the four-leaf stage. Therefore, rice during the seedling growth stage will be subjected to variable soil moisture content. A greenhouse experiment was conducted to evaluate the performance of 15 rice cultivars commonly grown in Mississippi of USA under early-season soil moisture stress. Twenty morpho-physiological parameters of rice seedlings subjected to three different levels(100%, 66% and 33% field capacity) of soil moisture, from 10 to 30 d after sowing, were measured. Significant moisture stress × treatment interaction(P < 0.001) was observed for most of the parameters. Further, the total drought response index(TDRI) was developed to score the cultivars for drought tolerance with the variation from 26.88 to 36.21. Accordingly, the cultivars were classified into different groups of tolerance. The cultivars CL152 and CL142-AR were classified as the least and the most tolerant to drought based on TDRI and standard deviation, respectively. Even though both total root(R^2 = 0.98) or shoot(R^2 = 0.76) drought responses indices were positively correlated with TDRI, root traits were important in deriving the indices. Therefore, TDRI could be used to select cultivars for drought tolerance in a given environment and develop rice varieties with early-season drought tolerance. However, further research is needed to identify and characterize tolerance at other stages to assist breeding programs in rice.展开更多
Drought(water shortage)can substantially limit the yield and economic value of rose plants(Rosa spp.).Here,we characterized the effect of exogenous calcium(Ca^(2+))on the antioxidant system and photosynthesis-related ...Drought(water shortage)can substantially limit the yield and economic value of rose plants(Rosa spp.).Here,we characterized the effect of exogenous calcium(Ca^(2+))on the antioxidant system and photosynthesis-related properties of rose under polyethylene glycol 6000(PEG6000)-induced drought stress.Chlorophyll levels,as well as leaf and root biomass,were significantly reduced by drought;drought also had a major effect on the enzymatic antioxidant system and increased concentrations of reactive oxygen species.Application of exogenous Ca^(2+)increased the net photosynthetic rate and stomatal conductance of leaves,enhanced water-use efficiency,and increased the length and width of stomata following exposure to drought.Organ-specific physiological responses were observed under different concentrations of Ca^(2+).Application of 5 mmol·L^(-1)Ca^(2+)promoted photosynthesis and antioxidant activity in the leaves,and application of 10 mmol·L^(-1)Ca^(2+)promoted antioxidant activity in the roots.Application of exogenous Ca^(2+)greatly enhanced the phenotype and photosynthetic capacity of potted rose plants following exposure to drought stress.Overall,our findings indicate that the application of exogenous Ca^(2+)enhances the drought resistance of roses by promoting physiological adaptation and that it could be used to aid the cultivation of rose plants.展开更多
Botanical herbicide has been a hot topic in the research and development of novel pesticides. The herbicidal activity and biochemical characteristics of the botanical compound drupacine were studied by evaluating its ...Botanical herbicide has been a hot topic in the research and development of novel pesticides. The herbicidal activity and biochemical characteristics of the botanical compound drupacine were studied by evaluating its effects on seed germination, seedling growth, morphological and physiological characteristics of Amaranthus retroflexus. Drupacine inhibited seed germination and seedling growth, and had a median inhibition concentration(IC50) value of 38.99 mg L-1against A. retroflexus root. The α-amylase activity and soluble sugar content in treated plants were significantly lower than that of the control. The expression of α-amylase gene was dosage-dependently inhibited compared to the untreated control. This suggested that inhibition of α-amylase activity was a mode of action on seed germination. The root hairs were significantly decreased and part of the root cap fell off after treatment with drupacine. The ultrastructure observation showed that cell damage of root tips increased with the treatment time. Drupacine also increased the relative conductivity and malondialdehyde(MDA) content. Peroxidase(POD), catalase(CAT), and superoxide dismutase(SOD) activities were significantly enhanced in the treatment compared to the control. These findings indicated that the physiological and biochemical reaction changes leading to morphological and membrane injuries were the main effects of drupacine on the inhibition of seedling growth. Drupacine can be developed as a botanical herbicide.展开更多
Water,minerals,nutrients,etc.,can be shared by physiological integration among inter-connected ramets of clonal plants.Nitrogen plays an important role in alleviating cadmium(Cd)stress for clonal plants.But how differ...Water,minerals,nutrients,etc.,can be shared by physiological integration among inter-connected ramets of clonal plants.Nitrogen plays an important role in alleviating cadmium(Cd)stress for clonal plants.But how different forms of nitrogen affect growth performance of clonal plants subjected to heterogeneous Cd stress still remains poorly understood.A pot experiment was conducted to investigate the differential effects of ammonium and nitrate on growth performance of Glechoma longituba under heterogeneous Cd stress.In the experiment,parent ramets of Glechoma longituba clonal fragments were respectively supplied with modified Hoagland solution containing 7.5 mM ammonium,7.5 mM nitrate or the same volume of nutrient solution without nitrogen.Cd solution with different concentrations(0,0.1 or 2.0 mM)was applied to offspring ramets of the clonal fragments.Compared with control(N-free),nitrogen addition to parent ramets,especially ammonium,significantly improved antioxidant capacity[glutathione(GSH),proline(Pro),peroxidase(POD,)superoxide dismutase(SOD)and catalase(CAT)],PSII activity[maximum quantum yield of PSII(F_(v)/F_(m))and effective quantum yield of PSII(ΦPSII)],chlorophyll content and biomass accumulation of the offspring ramets suffering from Cd stress.In addition,negative effects of nitrate on growth performance of whole clonal fragments were observed under Cd stress with high concentration(2.0 mM).Transportation or sharing of nitrogen,especially ammonium,can improve growth performance of clonal plants under heterogeneous Cd stress.The experiment provides insight into transmission mechanism of nitrogen among ramets of clonal plants suffering from heterogeneous nutrient supply.Physiological integration might be an important ecological strategy for clonal plants adapting to heterogeneous environment stress conditions.展开更多
基金funded by Mississippi Rice Promotion Board and United States Department of AgricultureNational Institute of Food and Agriculture(USDA-NIFA,Grant No.2013-34263-20931)sub-award to Mississippi State University(Grant No.G-7799-2)
文摘The majority of rice(Oryza sativa L.) produced in the southern USA is drill-seeded and grown under upland-like conditions because permanent flooding is established after the four-leaf stage. Therefore, rice during the seedling growth stage will be subjected to variable soil moisture content. A greenhouse experiment was conducted to evaluate the performance of 15 rice cultivars commonly grown in Mississippi of USA under early-season soil moisture stress. Twenty morpho-physiological parameters of rice seedlings subjected to three different levels(100%, 66% and 33% field capacity) of soil moisture, from 10 to 30 d after sowing, were measured. Significant moisture stress × treatment interaction(P < 0.001) was observed for most of the parameters. Further, the total drought response index(TDRI) was developed to score the cultivars for drought tolerance with the variation from 26.88 to 36.21. Accordingly, the cultivars were classified into different groups of tolerance. The cultivars CL152 and CL142-AR were classified as the least and the most tolerant to drought based on TDRI and standard deviation, respectively. Even though both total root(R^2 = 0.98) or shoot(R^2 = 0.76) drought responses indices were positively correlated with TDRI, root traits were important in deriving the indices. Therefore, TDRI could be used to select cultivars for drought tolerance in a given environment and develop rice varieties with early-season drought tolerance. However, further research is needed to identify and characterize tolerance at other stages to assist breeding programs in rice.
基金supported by the National Key Research and Development Program of China(Grant No.2018YFD1000400)Innovative Program for Graduate Student of Qingdao Agricultural University(Grant No.QNYCX22045).
文摘Drought(water shortage)can substantially limit the yield and economic value of rose plants(Rosa spp.).Here,we characterized the effect of exogenous calcium(Ca^(2+))on the antioxidant system and photosynthesis-related properties of rose under polyethylene glycol 6000(PEG6000)-induced drought stress.Chlorophyll levels,as well as leaf and root biomass,were significantly reduced by drought;drought also had a major effect on the enzymatic antioxidant system and increased concentrations of reactive oxygen species.Application of exogenous Ca^(2+)increased the net photosynthetic rate and stomatal conductance of leaves,enhanced water-use efficiency,and increased the length and width of stomata following exposure to drought.Organ-specific physiological responses were observed under different concentrations of Ca^(2+).Application of 5 mmol·L^(-1)Ca^(2+)promoted photosynthesis and antioxidant activity in the leaves,and application of 10 mmol·L^(-1)Ca^(2+)promoted antioxidant activity in the roots.Application of exogenous Ca^(2+)greatly enhanced the phenotype and photosynthetic capacity of potted rose plants following exposure to drought stress.Overall,our findings indicate that the application of exogenous Ca^(2+)enhances the drought resistance of roses by promoting physiological adaptation and that it could be used to aid the cultivation of rose plants.
基金funded by the Provincial Natural Science Foundation of Hebei for Excellent Young Scholar, China (C2021204071)the Science and Technology Project of Hebei Education Department (QN2021079)+1 种基金the Key Research and Development Project of Hebei Province (21326511D and 19226504D)the China Agriculture Research System of MOF and MARA (CARS-02)。
文摘Botanical herbicide has been a hot topic in the research and development of novel pesticides. The herbicidal activity and biochemical characteristics of the botanical compound drupacine were studied by evaluating its effects on seed germination, seedling growth, morphological and physiological characteristics of Amaranthus retroflexus. Drupacine inhibited seed germination and seedling growth, and had a median inhibition concentration(IC50) value of 38.99 mg L-1against A. retroflexus root. The α-amylase activity and soluble sugar content in treated plants were significantly lower than that of the control. The expression of α-amylase gene was dosage-dependently inhibited compared to the untreated control. This suggested that inhibition of α-amylase activity was a mode of action on seed germination. The root hairs were significantly decreased and part of the root cap fell off after treatment with drupacine. The ultrastructure observation showed that cell damage of root tips increased with the treatment time. Drupacine also increased the relative conductivity and malondialdehyde(MDA) content. Peroxidase(POD), catalase(CAT), and superoxide dismutase(SOD) activities were significantly enhanced in the treatment compared to the control. These findings indicated that the physiological and biochemical reaction changes leading to morphological and membrane injuries were the main effects of drupacine on the inhibition of seedling growth. Drupacine can be developed as a botanical herbicide.
基金This research was supported by Science and Technology Support Program of Sichuan Province(2016NYZ0021)Guizhou Environmental Protection Department(2016).
文摘Water,minerals,nutrients,etc.,can be shared by physiological integration among inter-connected ramets of clonal plants.Nitrogen plays an important role in alleviating cadmium(Cd)stress for clonal plants.But how different forms of nitrogen affect growth performance of clonal plants subjected to heterogeneous Cd stress still remains poorly understood.A pot experiment was conducted to investigate the differential effects of ammonium and nitrate on growth performance of Glechoma longituba under heterogeneous Cd stress.In the experiment,parent ramets of Glechoma longituba clonal fragments were respectively supplied with modified Hoagland solution containing 7.5 mM ammonium,7.5 mM nitrate or the same volume of nutrient solution without nitrogen.Cd solution with different concentrations(0,0.1 or 2.0 mM)was applied to offspring ramets of the clonal fragments.Compared with control(N-free),nitrogen addition to parent ramets,especially ammonium,significantly improved antioxidant capacity[glutathione(GSH),proline(Pro),peroxidase(POD,)superoxide dismutase(SOD)and catalase(CAT)],PSII activity[maximum quantum yield of PSII(F_(v)/F_(m))and effective quantum yield of PSII(ΦPSII)],chlorophyll content and biomass accumulation of the offspring ramets suffering from Cd stress.In addition,negative effects of nitrate on growth performance of whole clonal fragments were observed under Cd stress with high concentration(2.0 mM).Transportation or sharing of nitrogen,especially ammonium,can improve growth performance of clonal plants under heterogeneous Cd stress.The experiment provides insight into transmission mechanism of nitrogen among ramets of clonal plants suffering from heterogeneous nutrient supply.Physiological integration might be an important ecological strategy for clonal plants adapting to heterogeneous environment stress conditions.
