Photosynthetic parameters in seedlings of Eucalyptus grandis as affected by rate of nitrogen supply

Abstract

Seedlings of Eucalyptus grandis were grown at five different rates of nitrogen supply. Once steady-state growth rates were established, a detailed set of CO 2 and water vapour exchange measurements were made to investigate the effects of leaf nitrogen content ( N ), as determined by nitrogen supply rate, on leaf structural, photosynthetic, respiratory and stomatal properties. Gas exchange data were used to parametrize the Farquhar-von Caemmerer photosynthesis model. Leaf mass per area (LMA) was negatively correlated to N . A positive correlation was observed between both day ( R d ) and night respiration ( R n ) and N when they were expressed on a leaf mass basis, but no correlation was found on a leaf area basis. An R d / R n ratio of 0·59 indicated a significant inhibition of dark respiration by light. The maximum net CO 2 assimilation rate at ambient CO 2 concentration ( A max ), the maximum rate of potential electron transport ( J max ) and the maximum rate of carboxylation ( V cmax ) significantly increased with N , particularly when expressed on a mass basis. Although the maximum stomatal conductance to CO 2 ( g scmax ) was positively correlated with A max , there was no relationship between g scmax and N . Leaf N content influenced the allocation of nitrogen to photosynthetic processes, resulting in a decrease of the J max / V cmax ratio with increasing N . It was concluded that leaf nitrogen concentration is a major determinant of photosynthetic capacity in Eucalyptus grandis seedlings and, to a lesser extent, of leaf respiration and nitrogen partitioning among photosynthetic processes, but not of stomatal conductance.

Effect of nitrogen supply on growth and photosynthesis of sunflower plants grown in the greenhouse

“…Thus, in sunflower plants the fall in A with leaf age is not fully accounted to stomatal control but due to a decrease in the photosynthetic capacity as a consequence of photosynthetic apparatus degradation. The absence of any detectable effect of nitrogen supply on gs is consistent with the results and hypothesis reported by Grassi et al [25] that nitrogen is not related to stomatal conductance. Although nitrogen supply did not affect significantly gs, high N-grown plants had lower C i than low N-grown plants throughout most the experimental period ( Fig.…”

“…Lower rates of gs in low N-grown plants have been reported [22,23]. On the other hand, opposite effect [24] or no effect [12,25] by nitrogen are also reported. In this experiment, lower nitrogen supply did not change significantly gs of the target leaves, except for leaf 6 which had higher gs than leaf 6 of well nourished sunflower plants ( Fig.…”

Sex-specific carbon and nitrogen partitioning under N deposition in Populus cathayana

“…In our study, along with the continuous increase in soluble proteins under high N deposition, P n increased in females, not in males when compared to moderate N deposition. Such results suggested that increase in soluble proteins may account for the increase in CO 2 fixation partially in females, while increased soluble proteins were only a form of storage N in males (Grassi et al 2002). Correspondingly, we found that the PNUE was positively correlated with the protein fraction allocating to water-soluble proteins in females, but not in males.…”

Effect of Nitrogen Fertilization on Growth and Photosynthetic Nitrogen use Efficiency in Tobacco (Nicotiana tabacum L.)

“…Lower rates of g s in low N-grown plants have been reported [10,21]. On the other hand, opposite effect or no effect [22] by nitrogen are also reported.…”