Biology subjects

Yamori, W.

Publications and source records attributed to Yamori, W..

18 recordsLinked to original sources

bioRxiv2026

Root-to-shoot ABA transport by NPF2.4 and NPF2.5 links stomatal regulation to photosynthetic performance

Fluctuating light strongly limits photosynthetic efficiency in plants, yet the mechanisms coordinating stomatal dynamics with rapid photosynthetic induction remain incompletely understood. Here, through a forward physiological screen in Arabidopsis, we identify the abscisic acid (ABA) transporters NPF2.4 and NPF2.5 as regulators of photosynthetic responses to fluctuating light. Loss-of-function npf2.4 and npf2.5 mutants exhibited accelerated stomatal opening and photosynthetic induction during light transitions, resulting in enhanced biomass accumulation and seed yield without compromising long-term drought tolerance. NPF2.4 and NPF2.5 mediated ABA uptake in yeast and were predominantly expressed in the root pericycle and cortex/epidermal tissues, respectively. Reciprocal grafting, xylem sap ABA measurements, and ABA treatment to the roots demonstrated that both transporters regulate root-to-shoot ABA transport. Our findings reveal that root-derived ABA modulates stomatal dynamics and photosynthetic efficiency under fluctuating light, establishing long-distance hormone transport as a key regulator of plant carbon gain in dynamic environments.

plant biology↗

bioRxiv2026

OsPATROL1 overexpression accelerates stomatal opening to enhance photosynthetic induction and growth under fluctuating light in rice

Slow stomatal opening after increases in irradiance constrains carbon gain under fluctuating light, yet stomatal kinetics remain an underexplored target for crop improvement. Here, we investigated Oryza sativa PROTON ATPASE TRANSLOCATION CONTROL 1 (OsPATROL1), which encodes a Munc13-like protein implicated in stomatal regulation in Arabidopsis thaliana. OsPATROL1 overexpression had modest, condition-dependent effects on steady-state gas exchange and did not alter stomatal morphology or biochemical traits. In contrast, it consistently accelerated stomatal opening and photosynthetic induction, reducing the stomatal conductance time constant during induction by 41-43%. During 12 h of simulated natural fluctuating light, OsPATROL1-overexpressing plants maintained higher stomatal conductance and net CO2 assimilation rate, increasing cumulative assimilation by 8-12% while maintaining their intrinsic water-use efficiency (iWUE). Under artificial fluctuating light, overexpression alleviated growth reductions relative to steady light. Under glasshouse conditions, total biomass increased by 34-44%, accompanied by greater tiller number, root biomass, bleeding sap rate, and leaf nitrogen content. Taken together, these results indicate that OsPATROL1 overexpression accelerates stomatal opening, enhances photosynthetic induction and daytime carbon gain without compromising iWUE, and is associated with greater growth.

plant biology↗

bioRxiv2026

Moderate overexpression of PROTON GRADIENT REGULATION 5 improves photosynthetic performance and plant growth under fluctuating low light in Arabidopsis thaliana

Cyclic electron transport (CET) around photosystem I (PSI) is essential for maintaining photosynthetic efficiency by balancing ATP/NADPH production and protecting PSI from photoinhibition. Although the PROTON GRADIENT REGULATION 5 (PGR5)-dependent CET pathway is known to be critical under high or fluctuating light conditions, its role under fluctuating low light remains poorly understood. In natural environments, plants frequently experience prolonged low irradiance interspersed with brief sunflecks, making fluctuating low light a physiologically relevant condition. Here, we investigated Arabidopsis thaliana lines with graded PGR5 expression levels to evaluate the dose-dependent contribution of PGR5 to CET activity, photosynthetic regulation, and growth performance under both low light and fluctuating low light conditions. Moderate increase in the PGR5 protein level enhanced CET activity, accelerated photosynthetic induction, improved PSI protection and increased biomass accumulation under fluctuating low light. In contrast, excessive PGR5 accumulation impaired photosynthetic performance and reduced plant growth, indicating that optimal CET capacity requires precise tuning of PGR5 abundance. These results reveal a non-linear relationship between PGR5 protein levels and photosynthetic performance and demonstrate that moderate enhancement of CET improves plant productivity under fluctuating low light. Our findings highlight the importance of optimizing CET capacity to match dynamic light environments and suggest that fine-tuning PGR5 expression could be a promising strategy for improving crop performance under natural canopy conditions. Significance statementModerate increase in the PGR5 improves plant productivity, whereas excessive PGR5 accumulation impaired photosynthetic performance and reduced plant growth. Therefore, optimizing CET capacity by the fine-tuning PGR5 expression is important for improving crop productivity.

plant biology↗

bioRxiv2026

Cyclic electron transport via the NDH complex sustains photosynthesis and productivity under fluctuating and sub-optimal environments

The chloroplast NADH dehydrogenase-like (NDH) complex mediates cyclic electron transport (CET) around photosystem I (PSI) and contributes to photosynthetic regulation and photoprotection under various environmental stresses. Although NDH function has been extensively characterized under controlled conditions, NDH-deficient mutants often show only subtle phenotypes in such environments, leaving its physiological importance under naturally fluctuating field conditions poorly understood. Here, we evaluated growth, yield, and photosynthetic performance of NDH-deficient rice cultivated under field conditions. Mutant plants exhibited reduced biomass accumulation and grain yield compared with wild type. Detailed physiological analyses revealed that NDH deficiency markedly decreased PSI electron transport and CO2 assimilation, particularly under low temperature and sub-saturating irradiance. At moderate and high temperatures, reductions in carbon fixation were largely confined to low-light conditions, whereas at low temperatures, impairment extended across nearly the entire light response range. Under repetitive fluctuating light regimes, NDH-deficient plants showed progressive declines in photosynthesis accompanied by a selective decrease in PSI photochemical capacity without changes in PSII maximum efficiency, indicating PSI-specific photoinhibition. These findings demonstrate that NDH-dependent CET plays a crucial role in sustaining photosynthetic efficiency and crop productivity in dynamic field environments by stabilizing PSI redox balance and maintaining long-term carbon gain. Summary StatementNDH-dependent cyclic electron transport supports photosynthesis and yield in field-grown rice by maintaining PSI function under fluctuating light, low temperature, and sub-saturating irradiance.

plant biology↗

bioRxiv2026

Beyond Peak Wavelength: Spectral Bandwidth of Blue and Red-Blue Laser Diodes (LDs) Reprograms Photosynthesis, Canopy Architecture, Senescence, and Whole-Plant Growth

In indoor horticulture high planting densities often accelerate the senescence of lower leaves, increasing trimming frequency, reducing effective photosynthetic area, and raising labor costs. While spectral composition has been widely studied, the role of spectral bandwidth, particularly when peak wavelength is identical, remains poorly understood. Here, we used laser diodes (LDs) as narrow-band light sources to examine how spectral bandwidth influences photosynthesis, canopy architecture, leaf senescence, and plant growth under monochromatic blue light and combined red and blue (R+B) light in tobacco (Nicotiana tabacum L. Wisconsin-38), lettuce (Lactuca sativa L. Red Fire), and Arabidopsis thaliana (L.) Heynh. Col-0. Under monochromatic blue light, narrow-band LD blue (LDB) reduced CO{square} assimilation rates and shoot dry weight compared with broad-band LED blue (LEDB) across species. However, LEDB cultivation was accompanied by accelerated the senescence of lower leaves, a major limitation under dense planting. In contrast, plants grown under LDB developed a more upright canopy architecture, characterized by larger leaf angles, which was associated with improved light penetration and delayed the senescence of lower leaves. When red and blue light were combined, narrow-band LD lighting (LDR+B) mitigated stress induced by 24-hour continuous illumination and promoted coordinated improvements in photosynthetic performance, leaf expansion, and canopy architecture. These integrated responses resulted in consistently higher shoot fresh weight and a healthier physiological state, as indicated by higher chlorophyll content and lower anthocyanin accumulation, compared with broad-band LEDR+B. Together, our results demonstrate that spectral bandwidth, even when peak wavelength is held constant, is a critical parameter shaping plant growth strategies. Precise control of bandwidth enables partial decoupling of traits traditionally linked in the classic sun or shade leaf syndromes, allowing independent regulation of canopy architecture, leaf senescence, and plant growth. This study highlights spectral bandwidth as a powerful yet underutilized lever for optimizing canopy health and yield in indoor horticulture.

plant biology↗

bioRxiv2025

NPF4.6-mediated ABA transport modulates stomatal responses to fluctuating light

Stomatal responses to fluctuating light (FL) strongly influence photosynthetic efficiency and biomass accumulation in seed plants. The abscisic acid (ABA) transporter NPF4.6 (also known as NRT1.2 or AIT1) mediates hormone import into guard cells, but its physiological roles in leaves remain unclear. Here, we examined the functions of NPF4.6 in Arabidopsis thaliana by characterizing two independent loss-of-function mutants (npf4.6) under both steady and FL conditions. Compared with wild type, npf4.6 showed a 21-43% reduction in the half-time of stomatal opening and a 26-32% increase in the mean net CO2 assimilation rate under simulated field light conditions, resulting in a 41-48% increase in shoot biomass. In contrast, no marked differences in photosynthetic efficiency were observed between the wild type and npf4.6 under drought stress, suggesting that the role of NPF4.6 is more pronounced under well-watered, dynamic-light conditions. Overall, these findings demonstrate that NPF4.6 contributes to the fine-tuning of stomatal kinetics under variable light environments, and highlight hormone transport as a promising target for improving photosynthesis and growth in the field.

plant biology↗

bioRxiv2025

Far-Red Light in Early Growth Stages Boosts Lettuce Biomass and Preserves Anthocyanins

Background and AimsLight plays a dual role in plants, serving as both an energy source and a regulator of development from seedling to senescence. Recently, far-red (FR) radiation has gained attention in the controlled environment agriculture (CEA) science and grower community for its potential to enhance yield through canopy expansion and improved light capture, contributing positively to photosynthesis. This study explores how supplemental FR light promotes lettuce growth and morphology across weekly intervals as well as analyzing photosynthetic parameters, pigment accumulation, and anthocyanin gene expression. MethodsRed leaf lettuce (Lactuca sativa Red Fire) was grown in a commercial plant factory with artificial light for six weeks. 5000K white (W) light was maintained at 300 mol m-2 s-1, and FR, when supplemented, was added at 100 mol m-2 s-1 in addition to the 300 mol m-2 s-1 of W light. Four lighting treatments were tested under a 16 h photoperiod: (1) W for all 6 weeks ("W"), (2) 4 weeks of W followed by 2 weeks of supplemental FR ("W to W+FR"), (3) 4 weeks of FR supplementation followed by 2 weeks of only W ("W+FR to W"), and (4) W+FR for all 6 weeks ("W+FR"). Key ResultsThe shoot dry weight after 6 weeks in "W+FR", "W+FR to W" and "W to W+FR" was greater than "W". Both "W+FR" and "W+FR to W" showed a tendency for greater canopy expansion compared to "W" as well as "W to W+FR". There were no significant differences in stomatal conductance among the treatments. On the other hand, in both "W" and "W+FR to W" plants, CO2 assimilation rates were enhanced when FR light was supplemented during measurement, compared to when FR was not provided. Anthocyanin accumulation was greater in both "W" and "W+FR to W", consistent with the expression of key genes involved in the anthocyanin biosynthesis pathway, including anthocyanin synthase (ANS), flavanone 3-hydroxylase (F3H) and dihydroflavonol 4-reductase (DFR). ConclusionsThis study demonstrates that FR supplementation during the early growth stages of lettuce promotes biomass accumulation by enhancing both canopy expansion and photosynthetic activity, while maintaining high levels of functional compounds such as anthocyanins.

physiology↗

bioRxiv2025

Root Water Uptake and Photosynthesis Synergistically Enhance Drought Tolerance in Interspecific Hybrid Sugarcane

Sugarcane (Saccharum spp. hybrids) is a globally important crop for food and bioenergy, but its production is increasingly threatened by drought driven by climate change. Drought causes complex interactions between root function and leaf photosynthesis, but their underlying mechanisms remain largely unstudied in sugarcane. To address this knowledge gap, we grew up to eight sugarcane cultivars in one field and two pot experiments inside a rain-out shelter. The relative growth rate of these eight cultivars under both well-watered and water-limited conditions was largely explained by net assimilation rate, which depended on bleeding sap rate caused by root pressure. Among the cultivars, Harunoogi--a first-generation backcross cultivar between a wild relative (S. spontaneum) and a commercial cultivar--exhibited improved drought avoidance through adequate root water supply, whereas the commercial cultivar NiTn18 showed the opposite. Throughout the drought and recovery, Harunoogi exhibited significantly higher leaf area, stomatal conductance, chlorophyll content, and maximum amplitude of the reaction center chlorophyll of PSI than cultivar NiTn18, which resulted in a higher net photosynthetic rate and biomass. These results highlight the potential of improving both root function and photosynthesis as an effective approach to developing drought-tolerant sugarcane. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/662668v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@133d4eforg.highwire.dtl.DTLVardef@1e0ac0borg.highwire.dtl.DTLVardef@13f0b3dorg.highwire.dtl.DTLVardef@1fb1208_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2025

Sustainable Edamame Production in an Artificial Light Plant Factory with Improved Yield and Quality

A plant factory utilizing artificial light is an innovative agricultural model that enables efficient and sustainable crop production. However, its application to a diverse range of crops remains limited. Edamame, a highly nutritious legume, has gained global popularity, yet its long-term storage is challenging due to quality deterioration, restricting its market distribution to seasonal availability. In this study, we successfully cultivated edamame using three hydroponic systems-- nutrient film technique (NFT), rockwool, and aeroponics (mist culture)--within an LED plant factory. Among these, NFT demonstrated the highest fresh seed yield, which was comparable to or exceeded that of conventional field cultivation. The high yield was attributed to enhanced pod formation and biomass production under controlled conditions. Furthermore, although free amino acid content was lower in NFT cultivation, NFT-grown edamame exhibited significantly higher total sugar and isoflavone contents than field-grown counterparts, suggesting superior eating quality and nutritional benefits. These results indicate that NFT hydroponics is a promising method for stable, high-yield edamame production with enhanced nutritional properties. This study provides a foundation for expanding edamame cultivation in controlled environments, contributing to year-round supply and its potential application in urban and space agriculture.

plant biology↗

bioRxiv2025

A Novel Multilayer Cultivation Strategy Improves Light Utilization and Fruit Quality in Plant Factories for Tomato Production

Plant factories using artificial lighting are a promising solution to food security and urban agricultural challenges. However, cultivation of fruit-bearing crops such as tomatoes remains limited due to their high light demands, long growth periods, and tall plant structure. In this study, we aimed to develop an efficient cultivation system for tomatoes in a multilayer plant factory. Mini-tomatoes were hydroponically cultivated using white LEDs in a five-tier shelf system under two different cultivation methods. The conventional I-shaped method involved vertical growth on the top tier with downward lighting, while the novel S-shaped method trained each plant horizontally across the 2nd to 4th tiers with lateral lighting on each level. The S-shaped method enabled even light distribution, resulting in consistent photosynthetic rates throughout the canopy. In contrast, the I-shaped method suffered from strong light attenuation in the lower tiers, leading to reduced photosynthetic efficiency in shaded parts. Although total yield did not differ significantly between the two methods, the S-shaped method promoted earlier fruit maturation and improved fruit quality, including higher sugar content. Compared with greenhouse cultivation, plant factory conditions ensured stable temperature and lighting, leading to compact plant morphology, shorter internodes, and higher SPAD values. Moreover, fruit quality was more consistent year-round, with higher lycopene and sugar contents. This study demonstrates that the S-shaped cultivation system offers significant advantages in light use efficiency, plant management, and fruit quality. It represents a scalable approach for enhancing tomato production in plant factories and may facilitate the introduction of other high-light-demanding fruit crops into vertical farming systems.

plant biology↗

bioRxiv2025

High-Precision Lighting for Plants: Laser Diodes Outperform LEDs in Photosynthesis and Plant Growth

The optimization of plant productivity in indoor horticulture relies heavily on artificial light systems, which serve as the primary light source for plant growth. Although light-emitting diodes (LEDs) have been extensively studied in recent decades, there is limited research on laser diodes (LDs). LDs offer several advantages such as adjustable light wavebands, remote illumination that minimizes heat accumulation near plants, and enhanced energy efficiency. This study investigated the impact of red LD light on plant photosynthesis and growth, exploring its potential applications in indoor horticulture. The research examined the gas exchange of tobacco plants (Nicotiana tabacum L. cv. Wisconsin-38) under six red LED and LD light sources with varying spectral characteristics. Two specific light sources were selected for further study: LED 664 (emission peak at 664 nm, waveband of 625~678 nm) and LD 660 (emission peak at 660 nm, waveband of 657~664 nm) as they demonstrated the greatest gas exchange efficiency among the tested LED and LD light sources. These two light sources were then evaluated for their effects on photochemical efficiency, carbohydrate accumulation and plant growth. The present study showed that compared with LED 664, LD 660 significantly increased Y(II), qL, and starch accumulation in tobacco leaves. Additionally, after 12 d of continuous irradiation with LD 660, both tobacco and Arabidopsis plants exhibited increased photosynthetic capacity, and all three plant species showed increased shoot dry weights and leaf areas compared with those under LED 664. These findings suggest that LDs present significant advantages over LEDs for indoor plant production.

plant biology↗

bioRxiv2025

Cyt b6/f Complex Fine-Tunes PSI Stability and Photosynthetic Capacity Under Fluctuating Light

Plants encounter dynamic light fluctuations in natural habitats, requiring robust mechanisms to protect Photosystem I (PSI) against photoinhibition. The cytochrome (Cyt) b6/f complex plays a pivotal role in regulating electron flow and ensuring PSI stability under fluctuating light. However, its precise role in balancing PSI protection and photosynthetic capacity remains unclear. In this study, transgenic tobacco (Nicotiana tabacum L. W38) with reduced Cyt b6/f content was used to examine PSI tolerance to photoinhibition and photosynthetic performance under fluctuating light. Notably, the reduced Cyt b6/f content conferred significant protection of PSI against photoinhibition induced by fluctuating light, albeit at the expense of the electron transport capacity. Remarkably, PSI stability was maintained even under extreme fluctuating light conditions in the plants with lowest Cyt b6/f contents, highlighting a trade-off between photoprotection and photosynthetic capacity. These findings reveal that a reduction in Cyt b6/f content enhances PSI protection while adjusting electron transport capacity, making plants more adaptable in environments dominated by low light and transient sunflecks. This study provides new insights into the adaptive strategies of plants under dynamic light environments and underscores the potential of targeting Cyt b6/f for enhancing crop tolerance to fluctuating light conditions.

plant biology↗

bioRxiv2025

Chloroplast genome editing of Rubisco boosts photosynthesis and plant growth

Photosynthetic inefficiencies limit the productivity and sustainability of crop production and the resilience of agriculture to future societal and environmental challenges. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) has inherently low catalytic efficiency, making it a key target for photosynthesis and crop improvement. However, introducing mutations to the chloroplast-encoded Rubisco large subunit (rbcL), which contains the enzymes catalytic sites, is technically challenging. In this study, we successfully generated a range of chloroplast-genome-edited Arabidopsis thaliana plants targeting rbcL by a targeted base editor, ptpTALECD. The M309I and D397N substitutions in rbcL resulted in an increased Rubisco catalytic rate (kcat) without any reductions of Rubisco content, thereby enhancing photosynthetic rates and plant growth under both current atmospheric CO2 concentrations (i.e., 381 mol mol-1) and projected future concentrations (i.e., 549 mol mol-1). Cryo-electron microscopy (cryo-EM) structural analysis showed that the M309I and D397N substitutions, although located far from the catalytic site, induce structural alterations in the catalytic (60s) loops. Our findings highlight the potential of Rubisco engineering to improve plant photosynthesis and growth, and underscore the unique opportunities that chloroplast genome editing offers for enhancing photosynthesis and crop productivity and reducing atmospheric CO2 levels in a non-GMO context.

plant biology↗

bioRxiv2024

Morphological Plasticity and Reproductive Strategies of Kalanchoe Species in Invasive Spread

Kalanchoe species, originally introduced worldwide as ornamentals, are now reported to be spreading in many regions, including China. It is hypothesized that morphological plasticity and the production of asexual plantlets contribute to their successful invasion. To address the hypothesis, four species - Kalanchoe delagoensis Eckl. & Zeyh., Kalanchoe x houghtonii D. B. Ward, Kalanchoe laetivirens Desc. and Kalanchoe daigremontiana Raym. - Hamet & H. Perrier - were cultivated under contrasting light and water conditions, and their reproductive and vegetative traits were examined. The plants subjected to high light tended to prioritize plantlet production, accompanied by a reduction in vegetative growth. Two distinct reproductive strategies were observed: K. delagoensis and K. x houghtonii significantly increased plantlet production under high light conditions, whereas K. daigremontiana and K. laetivirens enhanced the fresh weight of individual plantlets without altering the total number produced. These results highlight the high plasticity of vegetative and reproductive growth in response to light and water availability. The increased production of plantlets may contribute to the widespread occurrence of Kalanchoe species in open fields.

plant biology↗

bioRxiv2024

PATROL1-mediated H+-ATPase translocation boosts plant growth under drought by optimizing root and leaf functions

Optimizing leaf photosynthesis and root water and mineral uptake in crops during drought is crucial for enhancing agricultural productivity under climate change. Although plasma membrane H+-ATPase plays a key role in plant physiological processes, its overexpression alone does not consistently improve growth. While PROTON ATPASE TRANSLOCATION CONTROL 1 (PATROL1) regulates H+-ATPase translocation in response to various environmental stimuli in leaves, its function in roots remains largely unknown. Here we show that H+-ATPase was coimmunoprecipitated with PATROL1 in roots of Arabidopsis thaliana. Micrografting between wild type and PATROL1 knockout or overexpression lines showed that PATROL1 are indispensable in both shoots and roots, indicating that root uptake and leaf photosynthesis are simultaneous limiting factors for plant growth under drought conditions. PATROL1 overexpression in whole plants resulted in a 41% increase above wild type in shoot dry weight under drought conditions. These findings highlight the potential of H+-ATPase regulation in roots as a new strategy to improve plant productivity, particularly under drought conditions.

plant biology↗

bioRxiv2024

Identification and Characterization of Compounds that Improve Plant Photosynthesis and Growth under Light Stress Conditions.

In order to satisfy the food and fuel demands of a growing population, global food production needs to increase by more than 50% before 2050. However, various environmental stresses in the natural environment inhibit plant growth and result in reduced yields. This is primarily caused by decreases in photosynthetic capacity. Thus, there is an urgent need to develop new strategies to improve agricultural productivity and ensure food security. In this study, a novel chemical-screening system with 96 well plates and leaf disks of tobacco was used to identify several anthraquinone derivatives that could relieve high light stress from plants. Treatments with these chemicals induced greater photosynthetic capacity after high light stress conditions for 20-72 hours (h) in tobacco and better plant growth after exposure to light stress for 96 hours in Arabidopsis and lettuces. The photoprotective effect of anthraquinone derivatives is closely related to chemical induced oxidation of PSI. Furthermore, there were no negative effects on plant growth in chemically treated plants under non-stressful conditions. Taken together, this study shows that anthraquinone derivatives can confer high light stress tolerance in plants, resulting in improved plant photosynthesis and growth in environments with light stress.

plant biology↗

bioRxiv2021

VISUAL network analysis reveals the role of BEH3 as a stabilizer in the secondary vascular development in Arabidopsis

During secondary growth in plants, vascular stem cells located in the cambium continuously undergo self-renewal and differentiation throughout the lifetime. Recent cell-sorting technique enables to uncover transcriptional regulatory framework for cambial cells. However, the mechanisms underlying the robust control of vascular stem cells have not been understood yet. By coexpression network analysis using multiple transcriptome datasets of an ectopic vascular cell transdifferentiation system using Arabidopsis cotyledons, VISUAL, we newly identified a cambium-specific gene module from an alternative approach. The cambium gene list included a transcription factor BES1/BZR1 homolog 3 (BEH3), whose homolog BES1 is known to control vascular stem cell maintenance negatively. Interestingly, the vascular size of the beh3 mutants showed a large variation, implying the role of BEH3 as a stabilizer. BEH3 almost lost the transcriptional repressor activity and functioned antagonistically with other BES/BZR members via competitive binding to the same motif BRRE. Indeed, mathematical modeling suggests that the competitive relationship among BES/BZRs leads to the robust regulation of vascular stem cells.

developmental biology↗

bioRxiv2020

Stomatal density affects gas diffusion and CO2 assimilation dynamics in Arabidopsis under fluctuating light

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 CO2 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 among four lines of Arabidopsis thaliana (L.): a wild-type (WT), a STOMAGEN/EPFL9-overexpressing line, STOMAGEN/EPFL9-silencing line, and an EPIDERMAL PATTERNING FACTOR 1 knockout line (epf1). Lower SD resulted in faster response of A owing to the faster response of gs to fluctuating light and higher water use efficiency without decreasing A. Higher SD resulted in a faster response of A because of the higher initial gs. epf1, with a moderate increase in SD, showed the larger carbon gain, attributable to the high capacity and fast response of A, yielding higher biomass production than WT under fluctuating light. The present study suggests that higher SD can be beneficial to improve biomass production in the plant under field conditions.

plant biology↗