Abstract:

Plant adaptation to its growing environment is reflected in physiological responses, such as stomatal conductance, photosynthetic rate, transpiration rates, and water use efficiency. We studied the influence of low light levels on leaf transpiration rate and stomal structure of young `Jingyu' grape plants, Vitis vinefera L. cv. Jingyu, grown for 30 days under different light intensities (65% shading and 85% shading). The transpiration rate, stomatal conductance, and water use efficiency were measured using a portable photosynthesis system, and the stomata were observed using a scanning electron microscope. The results showed that the leaf water potential of young grape plants grown under a low light environment was higher but water use efficiency was lower as compared to the controls. Transpiration rate and stomatal conductance responded slowly to varied light intensities, whereas the young grape plants grown under natural light environment were more sensitive to changing light intensities. For the young grape plants grown under low light environment, the horizontal axes of their stomata were broaden and the difference between “larger” and “smaller” stomata was reduced. The stomata protruded out of the epidermal wall and even distorted the cuticle of the epidermal surface. Our results showed that young grape plants were able to adapt to a low light environment, and their leaf transpiration characteristics were correlated with stomatal structure.