Stomatal, mesophyll conductance, and biochemical limitations to photosynthesis during induction

Abstract

The dynamics of leaf photosynthesis in fluctuating light affects carbon gain by plants. Mesophyll conductance (gm) limits CO2 assimilation rate (A) under the steady state, but the extent of this limitation under non-steady-state conditions is unknown. In the present study, we aimed to characterize the dynamics of gm and the limitations to A imposed by gas diffusional and biochemical processes under fluctuating light. The induction responses of A, stomatal conductance (gs), gm, and the maximum rate of RuBP carboxylation (Vcmax) or electron transport (J) were investigated in Arabidopsis (Arabidopsis thaliana (L.)) and tobacco (Nicotiana tabacum L.). We first characterized gm induction after a change from darkness to light. Each limitation to A imposed by gm, gs and Vcmax or J was significant during induction, indicating that gas diffusional and biochemical processes limit photosynthesis. Initially, gs imposed the greatest limitation to A, showing the slowest response under high light after long and short periods of darkness, assuming RuBP-carboxylation limitation. However, if RuBP-regeneration limitation was assumed, then J imposed the greatest limitation. gm did not vary much following short interruptions to light. The limitation to A imposed by gm was the smallest of all the limitations for most of the induction phase. This suggests that altering induction kinetics of mesophyll conductance would have little impact on A following a change in light. To enhance the carbon gain by plants under naturally dynamic light environments, attention should therefore be focused on faster stomatal opening or activation of electron transport.

Subcellular Dissection of a Simple Neural Circuit: Functional Domains of the Mauthner-Cell During Habituation

“…Previous works exploring the roles of SFNs in the startle circuit revealed their crucial role in eliciting a proper escape response, but were viewed as a rather unregulated and hard-wired input (Lorent et al, 2001;López-Schier, 2019). Furthermore, their involvement in habituation were excluded as they converge downstream of the M-cell soma (Marsden and Granato, 2015).…”

Acclimating Cucumber Plants to Blue Supplemental Light Promotes Growth in Full Sunlight

“…However, none of the treatments affected the rate of photosynthetic induction ( Supplementary Table 1 ), agreeing with our previous study showing that in tomatoes, acclimation to different R/B ratios had only minor effects on the rapidity of the A under FL ( Zhang et al, 2019 ). Photosynthetic induction rate is mainly determined by (1) Calvin cycle enzyme activities, e.g., Rubisco activation rate and (2) CO 2 diffusional limitation, e.g., transient stomatal limitation ( Taylor et al, 2020 ; Sakoda et al, 2021 ). Our results again indicate that manipulating the PAR light spectrum does not change Rubisco activation properties or transient stomatal limitation.…”

“…Thus, a promising strategy for increasing light use efficiency in the field is to improve the rate of photosynthetic induction ( Taylor and Long, 2017 ). The stomatal limitation is one of the major determinants of the rate of photosynthetic induction ( Sakoda et al, 2021 ) and is often affected by the growth light spectrum ( O’ Carrigan et al, 2014 ). Therefore, the light spectrum might also affect the rate of photosynthetic induction.…”

The Arbuscular Mycorrhizal Fungus Rhizophagus Clarus Improve Physiological Tolerance to Drought Stress in Soybean Plants

“…Stomatal closure, in an attempt to maintain plant turgor, may limit photosynthetic processes and compromise crop yield [57][58][59] . Low photosynthetic yield due to stomatal limitation was observed in plants exposed to water de cit.…”