Abstract: An experiment was conducted to examine the influence of soil water stress on the stomatal characters of greenhouse tomato leaves in May to August 2013. With Jingfen2 as the test material, four soil moisture grades were included in this experiment: well watered (70%-80% of water holding capacity), mild stress (60%-70% of water holding capacity), moderate stress (50%-60% of water holding capacity) and severe stress (30%-40% of water holding capacity). Digital microscopic imaging system and digital measuring system were applied to measure the stomatal length, width, aperture, and density. The results showed that the stomatal length and width, stomatal aperture and open ratio of tomato leaves decreased with the increase of water stress, and the reduction amplitude increased with the extension of stress time. Tomato stomatal length and width decreased synchronously, but the stomatal length was more significantly decreased than the stomatal width with the increase of water stress. The stomata gradually changed from long ovate to suborbicular. The stomatal density of the upper epidermis increased gradually, while the stomatal density of the lower epidermis presented a trend of decreasing first and then increasing. This study provided the scientific basis for water management of greenhouse tomato.

Key words: Panax notoginseng, non-photochemical quenching, photosynthesis, light intensity, photosynthetic induction