名古屋大学 · 農学・生物学
Sugiura教授の研究室では、植物の形態的・生理的応答が光・栄養環境にどのように最適化されるかを、全植物レベルの成長率を基準に理論的・実験的に解明しています。特に、葉・根の割合や葉内窒素含量、非構造的炭水化物の蓄積が光合成能に与える影響を、ホルモン制御や上下部間のシグナル伝達を含め、多角的に解析しています。また、光合成の自己調節機構や、根・茎の成長が葉の機能に与える影響についても、グラフト実験やホルモン処理を用いて解明を進めています。
Figures are computed from collected data and may differ slightly.
Plants exhibit higher leaf-to-root ratios (L/R) and lower leaf nitrogen content (N(area)) in low-light than in high-light environments, but an ecological significance of this trait has not been explained from a whole-plant perspective. This study aimed to theoretically and experimentally demonstrate whether these observed L/R and N(area) are explained as optimal biomass allocation that maximize whole-plant relative growth rate (RGR). We developed a model which predicts optimal L/R and N(area) in
It has been argued that accumulation of nonstructural carbohydrates triggers a decrease in Rubisco content, which downregulates photosynthesis. However, a decrease in the sink-source ratio in several plant species leads to a decrease in photosynthesis and increases in both structural and nonstructural carbohydrate content. Here, we tested whether increases in cell-wall materials, rather than starch content, impact directly on photosynthesis by decreasing mesophyll conductance. We measured variou
We evaluated the roles of gibberellins (GAs) and cytokinins (CKs) in regulation of morphological traits such as biomass allocation and leaf mass per area (LMA). Seedlings of Polygonum cuspidatum Siebold & Zucc. were grown under various light and N availabilities. We exogenously sprayed solutions of gibberellin (GA3), benzyl adenine (BA), uniconazole (an inhibitor of GA biosynthesis) or their mixtures on the aboveground parts, and changes in morphological and physiological traits and relative gro
To clarify whether excessive accumulation of total non-structural carbohydrate (TNC) causes down-regulation of photosynthesis in Raphanus sativus, we manipulated sink-source balance to alter TNC levels in source leaves and examined its effects on photosynthetic characteristics, whole-plant biomass allocation and anatomical characteristics of leaves and petioles. Comet and Leafy varieties with large and small hypocotyls were reciprocally grafted to change hypocotyl sink strength. They were grown
To reveal whether hypocotyl sink activities are regulated by the aboveground parts, and whether physiology and morphology of source leaves are affected by the hypocotyl sink activities, we conducted grafting experiments using two Raphanus sativus varieties with different hypocotyl sink activities. Comet (C) and Leafy (L) varieties with high and low hypocotyl sink activities were reciprocally grafted and resultant plants were called by their scion and stock such as CC, LC, CL and LL. Growth, leaf
The present results suggest that a downregulation of photosynthesis in response to increased levels of TNC in source leaves can result not only from decreases in Rubisco content, but also from anatomical factors, such as an increase in cell wall thickness leading to reduced chloroplast CO2 concentrations.
Decreases in photosynthetic rate, stomatal conductance (gs), and mesophyll conductance (gm) are often observed under elevated CO2 conditions. However, which anatomical and/or physiological factors contribute to the decrease in gm is not fully understood. Arabidopsis thaliana wild-type and carbon-metabolism mutants (gwd1, pgm1, and cfbp1) with different accumulation patterns of non-structural carbohydrates were grown at ambient (400 ppm) and elevated (800 ppm) CO2. Anatomical and physiological tr
Exploring the impact of elevated CO2 on photosynthesis is vital for understanding plant responses to climate change. In C3 plants, elevated CO2 concentrations generally enhance CO2 assimilation by increasing chloroplast CO2 concentration. However, the underlying mechanisms are complex since photosynthesis involves multiple physiological processes operating at different time scales and varying among plant species. In this review, we focused on the responses of key photosynthetic processes in crop
Plants plastically change their morphological and physiological traits in response to environmental changes, which are accompanied by changes in endogenous levels of phytohormones. Although roles of phytohormones in various aspects of plant growth and development were elucidated, their importance in the regulation of biomass allocation was not fully investigated. This study aimed to determine causal relationships among changes in biomass allocation, morphological and physiological traits, and en
Sink-source imbalance causes accumulation of nonstructural carbohydrates (NSCs) and photosynthetic downregulation. However, despite numerous studies, it remains unclear whether NSC accumulation or N deficiency more directly decreases steady-state maximum photosynthesis and photosynthetic induction, as well as underlying gene expression profiles. We evaluated the relationship between photosynthetic capacity and NSC accumulation induced by cold girdling, sucrose feeding, and low nitrogen treatment
We demonstrate that the system can be used for varietal differences between major crops in their response to drought, waterlogging, and salinity stress. This system enables high-throughput, long-term evaluation of water use characteristics, facilitating the selection and development of water-saving and stress-tolerant crop varieties.
Abstract Understanding comprehensive mechanisms of the downregulation of photosynthesis induced by accumulation of non-structural carbohydrates (NSCs) is essential for the future food security.x Despite numerous studies, whether NSCs accumulation directly affects steady-state maximum photosynthesis and photosynthetic induction, as well as underlying gene expression profiles, remains unknown so far. We evaluated the relationship between photosynthetic capacity and NSCs accumulation induced by col
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