scholarly journals Understanding Maize Response to Nitrogen Limitation in Different Light Conditions for the Improvement of Photosynthesis

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1932
Author(s):  
Aleksandra Urban ◽  
Paweł Rogowski ◽  
Wioleta Wasilewska-Dębowska ◽  
Elżbieta Romanowska

The photosynthetic capacity of leaves is determined by their content of nitrogen (N). Nitrogen involved in photosynthesis is divided between soluble proteins and thylakoid membrane proteins. In C4 plants, the photosynthetic apparatus is partitioned between two cell types: mesophyll cells and bundle sheath. The enzymes involved in the C4 carbon cycle and assimilation of nitrogen are localized in a cell-specific manner. Although intracellular distribution of enzymes of N and carbon assimilation is variable, little is known about the physiological consequences of this distribution caused by light changes. Light intensity and nitrogen concentration influence content of nitrates in leaves and can induce activity of the main enzymes involved in N metabolism, and changes that reduce the photosynthesis rate also reduce photosynthetic N use efficiency. In this review, we wish to highlight and discuss how/whether light intensity can improve photosynthesis in maize during nitrogen limitation. We described the general regulation of changes in the main photosynthetic and nitrogen metabolism enzymes, their quantity and localization, thylakoid protein abundance, intracellular transport of organic acids as well as specific features connected with C4 photosynthesis, and addressed the major open questions related to N metabolism and effects of light on photosynthesis in C4 plants.

In blue-green algae the hydrogen donors and carbon skeletons required in the fixation of elementary nitrogen may be supplied by the photosynthetic mechanism. Study of the kinetic relationships between the photosynthetic assimilation of carbon and the assimilation of nitrogen into the cell material of Anabaena cylindrica Lemm. has demonstrated correlations between the rates of the two processes consonant with the existence of such biochemical connexions. The effects of light intensity, carbon-dioxide concentration and nitrogen concentration were each studied at four different temperatures by determination of changes in amounts of cell carbon and cell nitrogen in cultures grown for 48 h. Temperature was found to have the most marked differential effect, both low and high temperatures depressing nitrogen assimilation to a greater extent than carbon assimilation. At any given temperature there was a close correlation between the rates of the two processes over a wide range of variation in other factors. Both carbon and nitrogen assimilation were found to be inhibited by relatively low concentrations of carbon dioxide. The rate of carbon assimilation per unit amount of cell nitrogen was found to be related in the usual way to light intensity, but to be reduced at low nitrogen concentrations. The relative rate of nitrogen assimilation was likewise found to be related in the expected way to nitrogen concentration but to increase with light intensity and to be reduced at carbon-dioxide concentrations limiting for carbon assimilation.


HortScience ◽  
2017 ◽  
Vol 52 (11) ◽  
pp. 1464-1470 ◽  
Author(s):  
Lingyun Yuan ◽  
Yujie Yuan ◽  
Shan Liu ◽  
Jie Wang ◽  
Shidong Zhu ◽  
...  

High temperature (HT) is a major environmental stress limiting oversummer production of nonheading Chinese cabbage (NHCC, Brassica campestris ssp. chinensis Makino). In the present study, the effects of HT on photosynthetic capacity, including light reaction and carbon assimilation, were completely investigated in two NHCC, ‘xd’ (heat-tolerant), and ‘sym’ (heat-susceptible). The two genotypes showed significant differences in plant morphology, photosynthetic capacity, and photosynthate metabolism (carboassimilation). HT caused a decrease in photosynthesis, chlorophyll contents, and photochemical activity in NHCC. However, these main photosynthetic-related parameters, including net photosynthetic rate (PN), maximal photochemical efficiency of PSII (Fv/Fm), and total chlorophyll content in ‘xd’, were significantly higher than those of ‘sym’ plants. The antioxidant contents and antioxidative enzyme activities of ascorbic acid-reduced glutathione cycle in the chloroplast of ‘xd’ were significantly higher than those of ‘sym’. Microscopic analyses revealed that HT affected the structure of photosynthetic apparatus and membrane integrity to a different extent, whereas ‘xd’ could maintain a better integrated chloroplast shape and thylakoid. Inhibited light reaction also hampered carbon assimilation, resulting in a decline of carboxylation efficiency and imbalance of carbohydrate metabolism. However, larger declined extents in these data were presented in ‘sym’ (heat-susceptible) than ‘xd’ (heat-tolerant). The heat-tolerant genotype ‘xd’ had a better capacity for self-protection by improved light reaction and carbon assimilation responding to HT stress.


2006 ◽  
Vol 44 (5-6) ◽  
pp. 387-394 ◽  
Author(s):  
E. Romanowska ◽  
B. Wróblewska ◽  
A. Droƶak ◽  
M. Siedlecka

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1778 ◽  
Author(s):  
Noushina Iqbal ◽  
Mehar Fatma ◽  
Harsha Gautam ◽  
Shahid Umar ◽  
Adriano Sofo ◽  
...  

Photosynthesis is a pivotal process that determines the synthesis of carbohydrates required for sustaining growth under normal or stress situation. Stress exposure reduces the photosynthetic potential owing to the excess synthesis of reactive oxygen species that disturb the proper functioning of photosynthetic apparatus. This decreased photosynthesis is associated with disturbances in carbohydrate metabolism resulting in reduced growth under stress. We evaluated the importance of melatonin in reducing heat stress-induced severity in wheat (Triticum aestivum L.) plants. The plants were subjected to 25 °C (optimum temperature) or 40 °C (heat stress) for 15 days at 6 h time duration and then developed the plants for 30 days. Heat stress led to oxidative stress with increased production of thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H2O2) content and reduced accrual of total soluble sugars, starch and carbohydrate metabolism enzymes which were reflected in reduced photosynthesis. Application of melatonin not only reduced oxidative stress through lowering TBARS and H2O2 content, augmenting the activity of antioxidative enzymes but also increased the photosynthesis in plant and carbohydrate metabolism that was needed to provide energy and carbon skeleton to the developing plant under stress. However, the increase in these parameters with melatonin was mediated via hydrogen sulfide (H2S), as the inhibition of H2S by hypotaurine (HT; H2S scavenger) reversed the ameliorative effect of melatonin. This suggests a crosstalk of melatonin and H2S in protecting heat stress-induced photosynthetic inhibition via regulation of carbohydrate metabolism.


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