Daisuke Yasutake

Carbon export from leaves as translocation is a result of plant coordination of leaf carbohydrate availability. Carbohydrate availability coordination is actively studied in model plants (Arabidopsis) under regulated conditions and can be optimized to increase productivity. However, in horticultural crops grown under field conditions, carbon export dynamics and coordination are poorly understood. The objective of this study was to analyze the dynamics of carbon export from leaves and the effects

In greenhouse cultivation, microclimate control is a highly energy-consuming process, and CO2 enrichment, which is a part of it, requires the direct consumption of fossil fuel energy. To achieve sustainable and economical greenhouse management, we must understand the performance and energy utilisation efficiency of CO2 enrichment in greenhouses. In this study, we conducted computational fluid dynamics (CFD) simulations for two CO2 enrichment methods in a strawberry greenhouse: (1) conventional o

We studied the effects of leaf wetting on midday depression of photosynthesis regarding plant water balance and leaf morphological traits. The plants without leaf wetting showed a significant reduction in midday photosynthesis with a concomitant decrease with leaf conductance, because of lower leaf water potential (-1.3 MPa) due to excessive transpiration water loss. However, midday depression was not observed in the plants with leaf wetting. Lower contact angle between leaf surface and water dr

Understanding how seasonal and annual variations in dew formation are controlled by environmental elements of a crop field is necessary for utilizing dew as a water resource for agricultural production. Radiative cooling intensity, wind speed, and water vapor pressure are the key environmental elements for the dew formation. However, a detailed investigation of how seasonal and annual variations in these environmental elements affect the variation in dew formation is unexplored. We examined the

Supplemental lighting techniques in greenhouses can increase plant growth and yield but require substantial amounts of energy. We proposed the use of energy-saving supplemental lighting, which was applied during rapid fruit development when the transport of photosynthetic products into the fruit was active. We measured the physiological responses (photosynthesis, growth, yield) of the strawberry plants with single fruit truss, wherein the following 3 treatments were made: plants were cultivated

CO₂ enrichment is an essential environmental control technology due to its significantly enhancing effect on crop production capacity. Despite being a key energy consumer in protected agriculture (i.e. greenhouse systems), CO₂ enrichment remains at a low energy use efficiency level, highlighting the need for developing more energy-efficiency strategies for CO₂ enrichment. Therefore, this study employed the computational fluid dynamics (CFD) simulation method to r

In order to analyze absorption and transport of water and ions in plants affecting the salinization in the root zone through physical and physiological processes, we measured water and ion uptake by roots, transpiration rate, leaf conductance, and ion concentrations in root xylem sap and other plant tissues of corn and sunflower grown under saline conditions using a nutrient film technique system. The rate of root water uptake was lower in corn than in sunflower, where the daytime stomatal closu

Abstract The carbon allocation in source leaves between sucrose and starch is an important mechanism that affects plant productivity. We previously found that strawberry plants accumulate starch in response to excess carbon supply from photosynthesis compared with translocation and sucrose storage capacity in source leaves. However, because these data were acquired from three separate cultivation seasons in field conditions, seasonal impacts could not be ruled out. Therefore, herein, we aimed to

Fogging and circulation systems were installed into a greenhouse to control daytime humidity and airflow at adequately high levels, with systems composed of 9 mist sprayers and 2 fans with a diameter of 0.3 m. The performance of the systems was examined by analyzing humidity (vapor pressure, relative humidity), wind speed, and leaf conductance (total conductance of stomata and leaf boundary layer) of cucumber plants under 2 conditions: with mist and fan treatment and with no treatment. Use of th

A whole-plant chamber system equipped with a transpiration sap flow meter was developed for measuring the transpiration rate even if leaves are wetted. A preliminary experiment in which dynamics of transpiration rate and/or evaporation rate of wetted and non-wetted plants were measured and compared with each other demonstrated the validity of the measurement system. The system was then used to analyse leaf wetting effects on gas exchange of corn under slight water stress conditions of soil (a vo

In order to elucidate stomatal response to wind, leaf gas exchange and stomatal conductance in an intact leaf of cucumber plants (Cucumis sativus L.) were measured under different conditions of air current and humidity. A leaf gas exchange cuvette was improved for individual measurements on the abaxial and adaxial leaf surfaces and for adjustment of the leaf boundary air current, where leaf boundary layer conductance can be adjusted at a desired value within a range from 0.3mol m^<-2>s^&lt