Agrotechnology

Spatiotemporal distribution of photosynthesis: Evaluation in a strawberry greenhouse under CO2 enrichment

13^th International Conference on Agriculture & Horticulture

September 10-12, 2018 | Zurich, Switzerland

Kensuke Kimura, Daisuke Yasutake and Masaharu Kitano

Kyushu University, Japan

Posters & Accepted Abstracts: Agrotechnology

Abstract:

Statement of the Problem: Achieving higher crop production in a greenhouse requires optimizing spatiotemporal variability of photosynthesis, which is the basic process underlying crop growth. However, there has been little research with a focus on spatiotemporal variations of photosynthesis in a greenhouse. Here, we conducted multipoint application of a photosynthesis model in a 6-span strawberry greenhouse under CO2 enrichment, to reveal the spatiotemporal distribution of photosynthesis. Methodology & Theoretical Orientation: Leaf photosynthetic rate (A) was evaluated by coupling the biochemical model for C3 photosynthesis with gas diffusion theory of the Fick???s law. Moreover, a midday depression of photosynthesis was simply modeled using accumulated evaporative demand during a daytime, assuming that the depression arises from a reduction in photosynthetic capacity (Vcmax and Jmax in the Farquhar model) induced by accumulation of midday environmental stresses (expressed by evaporative demand) to a leaf. Multipoint application of the model was performed as shown in Figure 1, thereby visualizing the spatiotemporal distribution of A in the greenhouse. Findings: The model could well capture time courses of A including the midday depression influenced by some environmental stresses. This indicates that accumulated evaporative demand may be applicable to the evaluation of the midday depression during a day. The spatiotemporal distribution of A under CO2 enrichment was strongly affected by the pattern of leaf boundary layer conductance (i.e., airflow) as well as that of CO2 concentration, and consequently remarkable non-uniformity in A appeared across the greenhouse. This result confirms the importance of controlling airflow for optimizing spatiotemporal variability of A under light wind conditions in the greenhouse. Conclusion & Significance: The multipoint application proposed herein contributes to spatiotemporal optimization of environmental controls in the greenhouse (e.g., CO2 enrichment, ventilation, and heating), leading to optimization of spatiotemporal variability of photosynthesis. Recent Publications: 1. Cabrera-Bosquet L et al. (2016) High-throughput estimation of incident light, light interception and radiation-use efficiency of thousands of plants in a phenotyping platform. New Phytologist. 212(1):269-281. 2. Kimura K et al. (2016) Leaf boundary layer conductance in a tomato canopy under the convective effect of circulating fans in a greenhouse heated by an air duct heater. Environmental Control in Biology. 54(4):171-176. 3. Kimura K et al. (2017) Dynamic distribution of thermal effects of an oscillating frost protective fan in a tea field. Biosystems Engineering. 164:98-109. 4. Li Y et al. (2018) Automatic carbon dioxide enrichment strategies in the greenhouse: a review. Biosystems Engineering. 171: 101-119 5. Xue W et al. (2017) A spatially hierarchical integration of close-range remote sensing, leaf structure and physiology assists in diagnosing spatiotemporal dimensions of field-scale ecosystem photosynthetic productivity. Agricultural and Forest Meteorology. 247:503-519.

Biography :

Kensuke Kimura is currently a PhD student at Kyushu University in Japan, specializing in Agricultural Meteorology. He is also a Research Fellow of Japan Society for the Promotion Science. His research consistently focuses on spatiotemporal variabilities of plant-environment transport phenomena (e.g. energy balance, transpiration and photosynthesis). He has evaluated spatiotemporal distributions of such phenomena in several types of agricultural fields, with the aid of continuousmultipoint measurements of microclimate using original sensor and many models of the transport phenomena including original models. He is now interested in the integration of close-range remote sensing technique with his previous works, to elucidate higher-resolution patterns of the plant-environment transport phenomena.

E-mail: kensuke.kimura.352@s.kyushu-u.ac.jp