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Observational data on dry matter accumulation (DMA) and dry matter partitioning (DMP) from the experiment of maize sown on four different dates in a normal year (2012) and three drought years (2014, 2015, 2018) were analyzed to assess the impact of drought and the sowing date on DMA and DMP in different above-ground organs. The phenology of maize was more closely related to the sowing date than to drought. In the normal year, the amount of dry matter in different organs differed slightly among sowing dates, except for those at maturity, and increased linearly after jointing: the dry matter of leaves and stalks increased rapidly before tasselling and the milk stage, respectively, and both increased slowly thereafter, whereas the dry matter of the ears increased linearly. In the drought years, DMA was more sensitive to precipitation relative to the normal year and was affected by the sowing date and drought. Specifically, drought lowered the dry matter of the above-ground organs to varying degrees and accentuated that variation in crops sown on different dates. From the view of DMP, a mild drought lowers the stalk DMP rate but increases the rate in ears. The more severe the drought, the smaller the DMP rate in ears and the stronger the inhibition of the transfer of dry matter from stalk to ears, as well as the more significant difference in the DMP pattern among the sowing dates. High temperatures and drought had a significant synergistic effect on DMAs in all the organs relative to that of drought alone, reversely having an inappreciable impact on the DMP pattern. During the three growth periods, namely jointing to tasselling, tasselling to the milk stage, and the milk stage to maturity, DMA during any two adjacent periods had a clear complementary effect, especially before and after tasselling. Dry matters of the above-ground parts in aggregate, of the stalk and of the ears, at the milk and maturity stages were negatively correlated to the degree of drought, and the maximum correlation was for the ears. [ABSTRACT FROM AUTHOR]

Observational data on dry matter accumulation (DMA) and dry matter partitioning (DMP) from the experiment of maize sown on four different dates in a normal year (2012) and three drought years (2014, 2015, 2018) were analyzed to assess the impact of drought and the sowing date on DMA and DMP in different above-ground organs. The phenology of maize was more closely related to the sowing date than to drought. In the normal year, the amount of dry matter in different organs differed slightly among sowing dates, except for those at maturity, and increased linearly after jointing: the dry matter of leaves and stalks increased rapidly before tasselling and the milk stage, respectively, and both increased slowly thereafter, whereas the dry matter of the ears increased linearly. In the drought years, DMA was more sensitive to precipitation relative to the normal year and was affected by the sowing date and drought. Specifically, drought lowered the dry matter of the above-ground organs to varying degrees and accentuated that variation in crops sown on different dates. From the view of DMP, a mild drought lowers the stalk DMP rate but increases the rate in ears. The more severe the drought, the smaller the DMP rate in ears and the stronger the inhibition of the transfer of dry matter from stalk to ears, as well as the more significant difference in the DMP pattern among the sowing dates. High temperatures and drought had a significant synergistic effect on DMAs in all the organs relative to that of drought alone, reversely having an inappreciable impact on the DMP pattern. During the three growth periods, namely jointing to tasselling, tasselling to the milk stage, and the milk stage to maturity, DMA during any two adjacent periods had a clear complementary effect, especially before and after tasselling. Dry matters of the above-ground parts in aggregate, of the stalk and of the ears, at the milk and maturity stages were negatively correlated to the degree of drought, and the maximum correlation was for the ears.

Water-saving cultivation in wheat (Triticum aestivum L.) is an important technique for achieving high yield and high water use eficiency (WUE) in the North China Plain (NCP) where water resources are in shortage. In order to determine the effects of supplemental irrigation based on soil water content on crop evapotranspiration (ET), DM, grain yield and WUE in wheat, treatments were designed to vary the relative soil water content at jointing and anthesis stages: I70 (70%, 70%) and I75 (75%, 75%) with rain-fed (I0) and traditional irrigation (Ick) as contrasts. The results indicated that the irrigation amount of I70 and I75 were significantly lower than that of Ick by 45.1 to 132.4 mm, but soil water depletion increased by 23.5 to 35.4 mm. Although the total ET throughout the growing season (ETt) of I75 was less than that of Ick, the ratio to ETt from anthesis to maturity increased significantly. The DM partitioning ratio was decreased in vegetable organs, but increased in grain for I75 compared with Ick. The grain yield for I75 was significantly higher than that of I0 and I70, whereas nonsignificant difference was observed between I75 and Ick, and the WUE and irrigation water use efficiency of I75 were higher than those of Ick by 11.0% and 87.4% in 2008-2009 and 3.5% and 34.0% in 2009-2010. Thus, I75 can be developed as an optimal water-saving irrigation regimes in the NCP. [ABSTRACT FROM AUTHOR]

A pot study was conducted to investigate influences of salinity on sugarcane (Saccharum spp.) plant growth, leaf photosynthesis, and other physiological traits during tillering and stalk elongation. Treatments included two commercial sugarcane cultivars (Canal Point (CP) 96-1252 and CP 00-1101) and an Erianthus with five different soil salt concentrations (0 [Control], 38, 75, 150, and 300 mM of NaCl added). Growth (tillers, plant height, and nodes) and physiological (leaf net photosynthetic rate [Pn], stomatal conductance [gs], intercellular CO2 concentration, and leaf water soluble sugar concentrations) characters were determined during the experiment. Responses of sugarcane growth, photosynthesis, and photoassimilate translocation to salinity depended on soil salt concentration. Plant height was the most sensitive while the number of nodes was the most tolerant to soil salinity among the three growth traits measured. CP 96-1252 differed from CP 00-1101 significantly in response of shoot:root ratio to high salt concentration. Leaf Pn of plants treated with the 38 mM salt did not differ from that of the control plant, but plants treated with the 75, 150, and 300 mM salt had 12.7, 18.7, and 35.3% lower leaf Pn, respectively, than the control. The low leaf Pn due to salinity was associated with not only the decrease in gs, but also the non-stomatal factors. Results of leaf sugar composition and concentrations revealed that high salt concentration also depressed photoassimilate translocation from leaves to other plant tissues. These findings are important for better understanding of some physiological mechanisms of salinity influence on sugarcane growth and yields.

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A pot study was conducted to investigate influences of salinity on sugarcane (Saccharum spp.) plant growth, leaf photosynthesis, and other physiological traits during tillering and stalk elongation. Treatments included two commercial sugarcane cultivars (Canal Point (CP) 96-1252 and CP 00-1101) and an Erianthus with five different soil salt concentrations (0 [Control], 38, 75, 150, and 300 mM of NaCl added). Growth (tillers, plant height, and nodes) and physiological (leaf net photosynthetic rate [Pn], stomatal conductance [gs], intercellular CO2 concentration, and leaf water soluble sugar concentrations) characters were determined during the experiment. Responses of sugarcane growth, photosynthesis, and photoassimilate translocation to salinity depended on soil salt concentration. Plant height was the most sensitive while the number of nodes was the most tolerant to soil salinity among the three growth traits measured. CP 96-1252 differed from CP 00-1101 significantly in response of shoot:root ratio to high salt concentration. Leaf Pn of plants treated with the 38 mM salt did not differ from that of the control plant, but plants treated with the 75, 150, and 300 mM salt had 12.7, 18.7, and 35.3% lower leaf Pn, respectively, than the control. The low leaf Pn due to salinity was associated with not only the decrease in gs, but also the non-stomatal factors. Results of leaf sugar composition and concentrations revealed that high salt concentration also depressed photoassimilate translocation from leaves to other plant tissues. These findings are important for better understanding of some physiological mechanisms of salinity influence on sugarcane growth and yields. [ABSTRACT FROM AUTHOR]