Kazuma Sakoda 교수

Stomatal density (<i>SD</i>) is closely associated with photosynthetic and growth characteristics in plants. In the field, light intensity can fluctuate drastically within a day. The objective of the present study is to examine how higher <i>SD</i> affects stomatal conductance (<i>g</i> _<i>s</i> ) and CO₂ assimilation rate (<i>A</i>) dynamics, biomass production and water use under fluctuating light. Here, we compared the photosynthetic and growth characteristics under cons

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 ra

Drought stress is a major limiting factor for crop growth and yield. Water availability in the field can cyclically change between drought and rewatering conditions, depending on precipitation patterns. Concurrently, light intensity under field conditions can fluctuate, inducing dynamic photosynthesis and transpiration during the crop growth period. The present study aimed to characterize carbon gain and water use in fluctuating light under drought and rewatering conditions in two major crops, n

Rubisco is the key enzyme responsible for photosynthetic CO2 fixation. Previously, we succeeded to increase the catalytic rate (kcat) of Rubisco by the overexpression of sorghum C4-type Rubisco small subunit (RbcS) in rice. These Rubisco are present as a chimera of sorghum RbcS and rice RbcS. In this study, we introduced an RNAi construct for rice RbcS into a sorghum RbcS overexpression line (SS10). Obtained double-transgenic lines iSS4 and iSS5 dominantly expressed sorghum RbcS and accumulated

The CO2 assimilation rate, N content, Rubisco activation state, and protein distribution to Rubisco and Rubisco activase in the leaf were analyzed for four soybean genotypes at two growth stages under field conditions. The CO2 assimilation rate was largely constant except for one genotype during the reproductive stage. Rubisco activation state significantly decreased with the increase of N content during this period in three of four genotypes. When standardized by total soluble protein amount, R

Abstract Stomatal density ( SD ) is closely associated with photosynthetic and growth characteristics in plants. In the field, light intensity can fluctuate drastically throughout a day. The objective of the present study is to examine how the change in SD affects stomatal conductance ( gs ) and CO 2 assimilation rate ( A ) dynamics, biomass production, and water use under fluctuating light. Here, we compared the photosynthetic and growth characteristics under constant and fluctuating light amon

Although photosynthetic response to light has been extensively studied at the single-leaf level, little is known about the response at the whole-plant level. The present study aims to reveal the differences in the photosynthetic response to light under steady and non-steady states between the single leaf and whole plant in <i>Arabidopsis thaliana</i> and to investigate the mechanisms underlying these differences with respect to leaf aging. First, we developed an open system for gas exchange meas

Soybean (Glycine max (L.) Merr.) is the most important crop as a major source of protein and oil for humans and farm animals. A further increase in soybean yield is required to meet the food demand from the rapidly growing human population. This chapter discusses the great potential of genetic diversity in leaf photosynthesis to lead toward soybean yield improvement by utilizing a molecular breeding approach. Previous studies have discovered considerable variations in the photosynthetic rate und

Tropospheric ozone (O ) significantly reduces rice yield. Koshihikari, a leading Japanese rice cultivar, has been recognized as an O tolerant cultivar; however, the mechanisms underlying its high O tolerance remain unknown. Therefore, we aimed to elucidate the genetic and physiological mechanisms underlying high O tolerance in Koshihikari. A series of chamber experiments were conducted to examine photosynthesis, growth, yield-related traits, and gene expression profiles under chronic O condition

Drought stress is a major limiting factor for crop growth and yield. Water availability in the field can cyclically change between drought and rewatering conditions, depending on precipitation patterns. Concurrently, light intensity under field conditions can fluctuate, inducing dynamic photosynthesis and transpiration during crop growth period. The present study aimed to characterize carbon gain and water use in fluctuating light under drought and rewatering conditions by conducting gas exchang

Subjects made voluntary saccades from the central fixation point to 5 deg in the right after the fixation point was turned off in darkness, while a continuously illuminated target was given at 5 deg in the left as a simple background target through a trial. A flash target was presented above the fixation point at the time near the saccade, and the subjects judged the distance between the background and flash targets perceptually. The results showed that the perceived distance between them reduce