To investigate the effects of exogenous lanthanum （La） on Alternanthera philoxeroides （Mart.） Griseb under perchlorate stress, changes in the growth and physiological parameters were investigated in solution cultu...To investigate the effects of exogenous lanthanum （La） on Alternanthera philoxeroides （Mart.） Griseb under perchlorate stress, changes in the growth and physiological parameters were investigated in solution culture experiments under controlled condi- tions. Different concentrations of La （NO3）3 were used in our study. It was shown that 0. 1 and 0.5 mg/L La3＋ alleviated the inhibition effect of perchlorate on A. philoxeroides, including relative growth yield, dry weight of different organs, leaf area and root activity. And La3＋ prevented decline in the relative chlorophyll content and chlorophyll fluorescence parameters including Fv/Fm, Fv＇/Frn＇, φPSll and ETR induced by perchlorate stress. Moreover, 0.5 mg/L La3＋ showed an optimal mitigative effect, while excess La3＋ （5.0 mg/L） led to synergistic effect on stress. Correlation analysis revealed a significant positive relationship between growth indexes and the chlorophyll fluorescence parameters, root activity and relative chlorophyll content （p〈0.05）. The results suggested that appropriate concentration of La3＋ could effectively alleviate growth inhibition and injury ofA. philoxeroides caused by perchlorate stress, and the mitigative effect of La3＋ might be achieved by improving root activity, maintaining chlorophyll content and promoting photochemical efficiency of photosystem II ofA. philoxeroides under perchlorate stress.展开更多
The stimulatory effects and associated mechanism of lanthanum nitrate on the root tuber yield of the traditional Chinese medicinal plant Pseudostellaria heterophylla, by means of improved photosynthetic characteristic...The stimulatory effects and associated mechanism of lanthanum nitrate on the root tuber yield of the traditional Chinese medicinal plant Pseudostellaria heterophylla, by means of improved photosynthetic characteristics, were investigated. Field experiments were conducted and the foliage was sprayed with varying concentrations of lanthanum nitrate. The results indicated that growth indexes, chlorophyll and carotenoid contents initially increased, and then decreased in a dose-dependent manner with increasing concentrations of lanthanum nitrate. The fresh and dry weights of root tuber yield per unit area significantly increased by 58.34% and 56.87% with a lanthanum nitrate concentration of 100 mg/L, respectively, compared with the control. Appropriate concentrations of lanthanum nitrate were found to alleviate photosynthetic depression at midday, as well as improve the mean values of photosynthetic rate（Pn）, stomatal conductance（Gs） and transpiration rate（Tr） associated with the diurnal variation in photosynthetic parameters, while reducing intercellular CO2 concentration（Ci）. During the experiment, the chlorophyll fluorescence parameters Fv/Fm, Fv＇/Fm＇, ΦPSII and qP increased initially and then decreased along with the increasing concentration of lanthanum nitrate, while NPQ followed the opposite trend. Correlation analysis revealed that Pn had a significantly positive relationship with seedling height, ground diameter, chlorophyll and carotenoid contents, Gs and ΦPSII, while a negative relationship was observed with Ci and NPQ. Grey relational analysis（GRA） indicated that photosynthetic pigments, ΦPSII and qP were the primary factors impacting photosynthesis. These results suggested that the application of an appropriate concentration of lanthanum nitrate（100 mg/L） was effective in improving growth, root tuber yield and photosynthetic characteristics of Psendoste llaria（P） heterophylla. The regulatory effect of lanthanum nitrate on photosynthesis was related to the promotion of light energy absorption and conversion, improvement in photochemical efficiency and the alleviation of photoinhibition. The improvement of the non-stomatal limitation factor was the primary basis for the mitigation of midday photosynthetic depression.展开更多
基金Foundation item： Project supported by Priority Academic Program Development of Jiangsu Higher Education Institutions （PAPD） and National Basic Research Program of China （2006CB403301）
文摘To investigate the effects of exogenous lanthanum （La） on Alternanthera philoxeroides （Mart.） Griseb under perchlorate stress, changes in the growth and physiological parameters were investigated in solution culture experiments under controlled condi- tions. Different concentrations of La （NO3）3 were used in our study. It was shown that 0. 1 and 0.5 mg/L La3＋ alleviated the inhibition effect of perchlorate on A. philoxeroides, including relative growth yield, dry weight of different organs, leaf area and root activity. And La3＋ prevented decline in the relative chlorophyll content and chlorophyll fluorescence parameters including Fv/Fm, Fv＇/Frn＇, φPSll and ETR induced by perchlorate stress. Moreover, 0.5 mg/L La3＋ showed an optimal mitigative effect, while excess La3＋ （5.0 mg/L） led to synergistic effect on stress. Correlation analysis revealed a significant positive relationship between growth indexes and the chlorophyll fluorescence parameters, root activity and relative chlorophyll content （p〈0.05）. The results suggested that appropriate concentration of La3＋ could effectively alleviate growth inhibition and injury ofA. philoxeroides caused by perchlorate stress, and the mitigative effect of La3＋ might be achieved by improving root activity, maintaining chlorophyll content and promoting photochemical efficiency of photosystem II ofA. philoxeroides under perchlorate stress.
基金Project supported by Postgraduate Research&Practice Innovation Program of Jiangsu Provice,Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Doctorate Fellowship Foundation of Nanjing Forestry University,National Training Programs of Innovation and Entrepreneurship for Undergraduates(201410298001Z)Training Programs of Innovation and Entrepreneurship for Undergraduates of Nanjing Forestry University(2015sjcx190)
文摘The stimulatory effects and associated mechanism of lanthanum nitrate on the root tuber yield of the traditional Chinese medicinal plant Pseudostellaria heterophylla, by means of improved photosynthetic characteristics, were investigated. Field experiments were conducted and the foliage was sprayed with varying concentrations of lanthanum nitrate. The results indicated that growth indexes, chlorophyll and carotenoid contents initially increased, and then decreased in a dose-dependent manner with increasing concentrations of lanthanum nitrate. The fresh and dry weights of root tuber yield per unit area significantly increased by 58.34% and 56.87% with a lanthanum nitrate concentration of 100 mg/L, respectively, compared with the control. Appropriate concentrations of lanthanum nitrate were found to alleviate photosynthetic depression at midday, as well as improve the mean values of photosynthetic rate（Pn）, stomatal conductance（Gs） and transpiration rate（Tr） associated with the diurnal variation in photosynthetic parameters, while reducing intercellular CO2 concentration（Ci）. During the experiment, the chlorophyll fluorescence parameters Fv/Fm, Fv＇/Fm＇, ΦPSII and qP increased initially and then decreased along with the increasing concentration of lanthanum nitrate, while NPQ followed the opposite trend. Correlation analysis revealed that Pn had a significantly positive relationship with seedling height, ground diameter, chlorophyll and carotenoid contents, Gs and ΦPSII, while a negative relationship was observed with Ci and NPQ. Grey relational analysis（GRA） indicated that photosynthetic pigments, ΦPSII and qP were the primary factors impacting photosynthesis. These results suggested that the application of an appropriate concentration of lanthanum nitrate（100 mg/L） was effective in improving growth, root tuber yield and photosynthetic characteristics of Psendoste llaria（P） heterophylla. The regulatory effect of lanthanum nitrate on photosynthesis was related to the promotion of light energy absorption and conversion, improvement in photochemical efficiency and the alleviation of photoinhibition. The improvement of the non-stomatal limitation factor was the primary basis for the mitigation of midday photosynthetic depression.
