Effects Of Soil Water Stress On Physiology And Biochemistry And Stomatal Development In Brassica Chinensis

In order to provide theoretical basis for their water supply during growing of 'youqing 60 days'(Brassica chinensis L. var. parachinensis (Bailey)), physiological indices of'youqing 60 days'seedling was examined under different soil water stress. The indices included the relative water content, chlorophyll content, proline content, soluble sugar content and malondialdehyde concent, 'youqing 60 days'stomatal density and stomatal apparatus size under water stress were also studyed. The main results are as follows:1. There were no significant change in the relative water content, chlorophyll content, proline content, soluble sugar content and malondialdehyde concent between different water treatments from first 1 to 8 d after treatment. With the stress time extension, relative water content decreased rapidly compared with that of control, the differences were significant or very significant. Under severe soil water stress condition, the chlorophyll content increased steadily compared with that of control. The proline content, soluble sugar content and malondialdehyde content significantly increased with the degree of soil water stress.2. The leaf stomatal density showed a single peak curve with the increase of water stress. With the further increase of stress levels, stomatal density first increased, and then decreased significantly.3. Under different water treatments, both length and width of leaf stomatal apparatus decreased, but the difference was not significant. This shows that stomatal apparatus size response to water stress is not significant.