Seven-day-old maize (Zea mays) plants were grown hydroponically for ten days in deprived nutrient solutions against the corresponding control grown under full nutrition;the effects of S-, N- or P-deprivation on lamina...Seven-day-old maize (Zea mays) plants were grown hydroponically for ten days in deprived nutrient solutions against the corresponding control grown under full nutrition;the effects of S-, N- or P-deprivation on laminas’ mean stomatal conductance (gs), transpiration rate (E) and photosynthetic rate (A) were monitored, along with the impact on the laminas’ total dry mass (DM), water amount (W), length and surface area (Sa). Furthermore, a time series analysis of each parameter’s response ratios (Rr), i.e. the treatment’s value divided by the corresponding control’s one, was performed. Under S-deprivation, the Rr of laminas’ mean gs, E, and A presented oscillations within a ±15% fluctuation zone, notably the “control” zone, whilst those of laminas’ total DM, water amount, surface area, and length included oscillation during the first days and deviation later on, presenting deviation during d10. Under the N-deprivation conditions all Rr time courses except the A one, included early deviations from the control zone without recovering. The deviation from the control zone appeared at d4. Under P-deprivation, all Rr time courses represented oscillations within the control zone. P-deprivation’s patterns resembled those of S-deprivation. Compared to the one of the S-deprivation, the P-one’s oscillations took place within a broader zone. Linear relationships among the various Rr patterns were found between gs-E, gs-A, E-A, DM-W and DM-Sa. In conclusion, the impact of P-deprivation appeared in an early stage and included an alleviation action, the one of N-deprivation appeared early with no alleviation action, whilst that of S-deprivation appeared later, being rather weaker when compared to the impact of the P-deprivation’s impact.展开更多
Intercropping is used widely by smallholder farmers in developing countries to increase land productivity and profitability. We conducted a maize/peanut intercropping experiment in the 2015 and 2016 growing seasons in...Intercropping is used widely by smallholder farmers in developing countries to increase land productivity and profitability. We conducted a maize/peanut intercropping experiment in the 2015 and 2016 growing seasons in Shandong, China. Treatments included sole maize (SM), sole peanut (SP), and an intercrop consisting of four rows of maize and six rows of peanut (IM and IP). The results showed that the intercropping system had yield advantages based on the land equivalent ratio (LER) values of 1.15 and 1.16 in the two years, respectively. Averaged over the two years, the yield of maize in the intercropping was increased by 61.05% compared to that in SM, while the pod yield of peanut was decreased by 31.80% compared to SP. Maize was the superior competitor when intercropped with peanut, and its productivity dominated the yield of the intercropping system in our study. The increased yield was due to a higher kernel number per ear (KNE). Intercropping increased the light transmission ratio (LTR) of the ear layer in the maize canopy, the active photosynthetic duration (APD), and the harvest index (HI) compared to SM. In addition, intercropping promoted the ratio of dry matter accumulation after silking and the distribution of 13C-photosynthates to grain compared to SM. In conclusion, maize/peanut intercropping demonstrated the potential to improve the light condition of maize, achieving enhanced photosynthetic characteristics that improved female spike differentiation, reduced barrenness, and increased KNE. Moreover, dry matter accumulation and 13C-photosynthates distribution to grain of intercropped maize were improved, and a higher grain yield was ultimately obtained.展开更多
Besides leaves, non-foliar green organs such as stem and spike are also considered photosynthetic organs. To assess the photosynthetic contributions of these organs, the correlations between these photosynthetic areas...Besides leaves, non-foliar green organs such as stem and spike are also considered photosynthetic organs. To assess the photosynthetic contributions of these organs, the correlations between these photosynthetic areas and single-spike weight were investigated in a winter wheat(Triticum aestivum L.) under four nitrogen and mulching treatments: N120,N150, N195, and N195 + M. Two-year repeated field experiments were conducted on the Loess Plateau of China. Non-foliar photosynthetic area, grain-filling ratio and duration,grain yield, and in particular, single-spike weight, were measured, recorded and analyzed.Under the N195 + M treatment, plants showed the largest area of photosynthetic organs(flag leaf and non-foliar organs) and the highest grain yield and single spike weight. Singlespike weight was positively correlated with the areas of all examined non-foliar photosynthetic organs, in particular with the area above the flag leaf node(R^2= 0.761*)and the area above the exposed part of the peduncle(EXP)(R^2= 0.800**). In addition, singlespike weight was highly correlated with average grain-filling ratio(R^2= 0.993**), whereas it was less highly correlated with grain-filling duration(R^2= 0.533). The morphological traits of non-foliar photosynthetic organs were also more highly correlated with average grainfilling ratio than with average grain-filling duration. The significant correlation between each of the morphological traits(area, length and width) of EXP and single-spike weight indicates that morphological traits of EXP are important in determining spike weight in the Loess Plateau environment.展开更多
Seven-day-old maize (Zea mays) plants were grown hydroponically for ten days in N-deprived nutrient solution. The distribution profiles according to the position on the stem of the –N laminas stomatal conductance, tr...Seven-day-old maize (Zea mays) plants were grown hydroponically for ten days in N-deprived nutrient solution. The distribution profiles according to the position on the stem of the –N laminas stomatal conductance, transpiration rate, photosynthetic rate (1st-group) were monitored, along with the corresponding profiles of dry mass, water amount, water content, length, surface area, and specific surface area (2nd-group), relative to control. In the uppermost –N laminas, the changes within a parameter of the 1st-group were significantly higher and of the 2nd-group significantly lower than the control, respectively. Correlations of the corresponding values among the parameters of the 1st-or 2nd-group were linear. The parameters between groups correlated non-linearly. Transpiration rate was divided by the lamina’s dry mass correlated with surface area in a power-type function. The slopes of the response ratios linear relations between the various pairs of parameters could be used for simulation of a lamina’s response to the deprivation.展开更多
Photosynthetic rate (Pn) and the partitioning of noncyclic photosynthetic electron transport to photorespiration (Jo) in seedlings of four subtropical woody plants growing at three light intensities were studied in th...Photosynthetic rate (Pn) and the partitioning of noncyclic photosynthetic electron transport to photorespiration (Jo) in seedlings of four subtropical woody plants growing at three light intensities were studied in the summer time by measurements of chlorophyll fluorescence and CO2 exchange. Except Schima superba, an upper canopy tree species, the tree species Castanopsis fissa and two understory shrubs Psychotria rubra, Ardisia quinquegona had the highest Pn at 36% of sunlight intensity. The total photosynthetic electron transport rate (JF) and the ratio of Jo/JF were elevated in leaves under full sunlight. Jo/JF ratio reached 0.5-0.6 and coincided with the increasing of oxygenation rate of Rubisco (Vo), the activity of glycolate oxidase and photorespiration rate at full sunlight. It is suggested that an increasing partitioning proportion of photosynthetic electron transport to photorespiration might be one of the protective regulation mechanisms in forest plant under strong summer light and high temperature conditions.展开更多
文摘Seven-day-old maize (Zea mays) plants were grown hydroponically for ten days in deprived nutrient solutions against the corresponding control grown under full nutrition;the effects of S-, N- or P-deprivation on laminas’ mean stomatal conductance (gs), transpiration rate (E) and photosynthetic rate (A) were monitored, along with the impact on the laminas’ total dry mass (DM), water amount (W), length and surface area (Sa). Furthermore, a time series analysis of each parameter’s response ratios (Rr), i.e. the treatment’s value divided by the corresponding control’s one, was performed. Under S-deprivation, the Rr of laminas’ mean gs, E, and A presented oscillations within a ±15% fluctuation zone, notably the “control” zone, whilst those of laminas’ total DM, water amount, surface area, and length included oscillation during the first days and deviation later on, presenting deviation during d10. Under the N-deprivation conditions all Rr time courses except the A one, included early deviations from the control zone without recovering. The deviation from the control zone appeared at d4. Under P-deprivation, all Rr time courses represented oscillations within the control zone. P-deprivation’s patterns resembled those of S-deprivation. Compared to the one of the S-deprivation, the P-one’s oscillations took place within a broader zone. Linear relationships among the various Rr patterns were found between gs-E, gs-A, E-A, DM-W and DM-Sa. In conclusion, the impact of P-deprivation appeared in an early stage and included an alleviation action, the one of N-deprivation appeared early with no alleviation action, whilst that of S-deprivation appeared later, being rather weaker when compared to the impact of the P-deprivation’s impact.
基金support of the National Key Research and Development Program of China (2017YFD0301001)the National Natural Science Foundation of China (31301274 and 31171497)+1 种基金funds from the Shandong “Double Tops” Program, China (SYL2017XTTD14)the Open Project of State Key Laboratory of Crop Biology in Shandong Agricultural University, China (2018KF10)
文摘Intercropping is used widely by smallholder farmers in developing countries to increase land productivity and profitability. We conducted a maize/peanut intercropping experiment in the 2015 and 2016 growing seasons in Shandong, China. Treatments included sole maize (SM), sole peanut (SP), and an intercrop consisting of four rows of maize and six rows of peanut (IM and IP). The results showed that the intercropping system had yield advantages based on the land equivalent ratio (LER) values of 1.15 and 1.16 in the two years, respectively. Averaged over the two years, the yield of maize in the intercropping was increased by 61.05% compared to that in SM, while the pod yield of peanut was decreased by 31.80% compared to SP. Maize was the superior competitor when intercropped with peanut, and its productivity dominated the yield of the intercropping system in our study. The increased yield was due to a higher kernel number per ear (KNE). Intercropping increased the light transmission ratio (LTR) of the ear layer in the maize canopy, the active photosynthetic duration (APD), and the harvest index (HI) compared to SM. In addition, intercropping promoted the ratio of dry matter accumulation after silking and the distribution of 13C-photosynthates to grain compared to SM. In conclusion, maize/peanut intercropping demonstrated the potential to improve the light condition of maize, achieving enhanced photosynthetic characteristics that improved female spike differentiation, reduced barrenness, and increased KNE. Moreover, dry matter accumulation and 13C-photosynthates distribution to grain of intercropped maize were improved, and a higher grain yield was ultimately obtained.
基金the financial support of the National Basic Research Program of China (2015CB150402)National Natural Science Foundation of China (51479189)+1 种基金Open Foundation of State Key Laboratory, Institute of Water and Soil Conservation, Chinese Academy of Sciences, Ministry of Water Resources (A314021402-1610)Key Research Foundation of Baoji University of Arts and Sciences (ZK16066)
文摘Besides leaves, non-foliar green organs such as stem and spike are also considered photosynthetic organs. To assess the photosynthetic contributions of these organs, the correlations between these photosynthetic areas and single-spike weight were investigated in a winter wheat(Triticum aestivum L.) under four nitrogen and mulching treatments: N120,N150, N195, and N195 + M. Two-year repeated field experiments were conducted on the Loess Plateau of China. Non-foliar photosynthetic area, grain-filling ratio and duration,grain yield, and in particular, single-spike weight, were measured, recorded and analyzed.Under the N195 + M treatment, plants showed the largest area of photosynthetic organs(flag leaf and non-foliar organs) and the highest grain yield and single spike weight. Singlespike weight was positively correlated with the areas of all examined non-foliar photosynthetic organs, in particular with the area above the flag leaf node(R^2= 0.761*)and the area above the exposed part of the peduncle(EXP)(R^2= 0.800**). In addition, singlespike weight was highly correlated with average grain-filling ratio(R^2= 0.993**), whereas it was less highly correlated with grain-filling duration(R^2= 0.533). The morphological traits of non-foliar photosynthetic organs were also more highly correlated with average grainfilling ratio than with average grain-filling duration. The significant correlation between each of the morphological traits(area, length and width) of EXP and single-spike weight indicates that morphological traits of EXP are important in determining spike weight in the Loess Plateau environment.
文摘Seven-day-old maize (Zea mays) plants were grown hydroponically for ten days in N-deprived nutrient solution. The distribution profiles according to the position on the stem of the –N laminas stomatal conductance, transpiration rate, photosynthetic rate (1st-group) were monitored, along with the corresponding profiles of dry mass, water amount, water content, length, surface area, and specific surface area (2nd-group), relative to control. In the uppermost –N laminas, the changes within a parameter of the 1st-group were significantly higher and of the 2nd-group significantly lower than the control, respectively. Correlations of the corresponding values among the parameters of the 1st-or 2nd-group were linear. The parameters between groups correlated non-linearly. Transpiration rate was divided by the lamina’s dry mass correlated with surface area in a power-type function. The slopes of the response ratios linear relations between the various pairs of parameters could be used for simulation of a lamina’s response to the deprivation.
文摘Photosynthetic rate (Pn) and the partitioning of noncyclic photosynthetic electron transport to photorespiration (Jo) in seedlings of four subtropical woody plants growing at three light intensities were studied in the summer time by measurements of chlorophyll fluorescence and CO2 exchange. Except Schima superba, an upper canopy tree species, the tree species Castanopsis fissa and two understory shrubs Psychotria rubra, Ardisia quinquegona had the highest Pn at 36% of sunlight intensity. The total photosynthetic electron transport rate (JF) and the ratio of Jo/JF were elevated in leaves under full sunlight. Jo/JF ratio reached 0.5-0.6 and coincided with the increasing of oxygenation rate of Rubisco (Vo), the activity of glycolate oxidase and photorespiration rate at full sunlight. It is suggested that an increasing partitioning proportion of photosynthetic electron transport to photorespiration might be one of the protective regulation mechanisms in forest plant under strong summer light and high temperature conditions.
