Diaheliotropic leaf movement enhances leaf photosynthetic capacity and photosynthetic light and nitrogen use efficiency via optimising nitrogen partitioning among photosynthetic components in cotton (Gossypium hirsutum L.)

Abstract

Phototropic leaf movement of plants is an effective mechanism for adapting to light conditions. Light is the major driver of plant photosynthesis. Leaf N is also an important limiting factor on leaf photosynthetic potential. Cotton (Gossypium hirsutum L.) exhibits diaheliotropic leaf movement. Here, we compared the long-term photosynthetic acclimation of fixed leaves (restrained) and free leaves (allowed free movement) in cotton. The fixed leaves and free leaves were used for determination of PAR, leaf chlorophyll concentration, leaf N content and leaf gas exchange. The measurements were conducted under clear sky conditions at 0, 7, 15 and 30 days after treatment (DAT). The results showed that leaf N allocation and partitioning among different components of the photosynthetic apparatus were significantly affected by diaheliotropic leaf movement. Diaheliotropic leaf movement significantly increased light interception per unit leaf area, which in turn affected leaf mass per area (LMA), leaf N content (N ) and leaf N allocation to photosynthesis (N ). In addition, cotton leaves optimised leaf N allocation to the photosynthetic apparatus by adjusting leaf mass per area and N in response to optimal light interception. In the presence of diaheliotropic leaf movement, cotton leaves optimised their structural tissue and photosynthetic characteristics, such as LMA, N and leaf N allocation to photosynthesis, so that leaf photosynthetic capacity was maximised to improve the photosynthetic use efficiency of light and N under high light conditions.

Effects of soil nitrogen (N) deficiency on photosynthetic N-use efficiency in N-fixing and non-N-fixing tree seedlings in subtropical China

“…The N allocation fractions of each component in the photosynthetic apparatus were calculated according to Niinemets and Tenhunen 13 , which has been widely used in recent years 1,45,78 .where C Chl is the chlorophyll concentration (mmol g −1 ), V cr is the specific activity of Rubisco (μmol CO 2 g −1 Rubisco s −1 ), J mc is the potential rate of photosynthetic electron transport (μmol electrons μmol −1 Cyt f s −1 ), and C B is the ratio of leaf chlorophyll to leaf N during light-harvesting (mmol Chl (g N) −1 ). The V cr , J mc , and C B were calculated according to Niinemets and Tenhunen 13 .…”

Seedling leaves allocate lower fractions of nitrogen to photosynthetic apparatus in nitrogen fixing trees than in non-nitrogen fixing trees in subtropical China

“…The fraction of leaf N allocated to Rubisco ( P R ), bioenergetics ( P B ), and the light-harvesting components ( P L ) (g g –1 )were calculated from V cmax , J max and chlorophyll contents using the method of Niinemets and Tenhunen [12], which has been widely used in recent years [15, 56–58]: …”

Seedling leaves allocate lower fractions of nitrogen to photosynthetic apparatus in nitrogen fixing trees (Dalbergia odorifera and Erythrophleum fordii) than in non-nitrogen fixing trees (Betula alnoides and Castanopsis hystrix) in subtropical China

“…The fraction of leaf N allocated to Rubisco ( P R ,), bioenergetics ( P B ), and the light-harvesting components ( P L ) (g g −1 ) were calculated from V cmax , J max and chlorophyll contents using the method of Niinemets and Tenhunen [7], which has been widely used in recent years [10, 59-61]: where C Chl is the chlorophyll concentration (mmol g −1 ), V cr is the specific activity of Rubisco (μmol CO 2 g −1 Rubisco s −1 ), J mc is the potential rate of photosynthetic electron transport (μmol electrons μmol −1 Cyt f s −1 ), and C B is the ratio of leaf chlorophyll to leaf N during light-harvesting (mmol Chl (g N) −1 ). V cr , J mc , and C B were calculated according to Niinemets and Tenhunen [7].…”