Effects of soil moisture levels on photosynthesis, transpiration, and moisture use efficiency of female and male plants of Hippophae rhamnoides ssp. Sinensis
Abstract:Net photosynthesis and transpiration rates of female and male individuals of Hippophae rhamnoides ssp. sinensis were measured under different soil moisture conditions using the LI-6400 portable photosynthesis system. We studied two habitats corresponding to high (gully) and low (slope) soil moisture. We also applied four levels of soil moisture to plants grown in our experimental farm. The results showed that H. rhamnoides ssp. sinensis performed better under higher soil moisture conditions. Net photosynthesis and transpiration rates were mainly affected by photosynthetically active radiation (PAR) and air temperature (TA). Male plants were characterized by higher photosynthesis and transpiration rates and higher moisture use efficiency. When soil conditions were drier, female and male individuals adapted by reducing transpiration and increasing moisture use efficiency. During these periods more factors affected Net photosynthetic and transpiration rates. Photosynthetic rate of male individuals decreased greatly, whereas female plants maintained higher photosynthetic rate and exhibited higher moisture use efficiency. We conclude that female individuals of H. rhamnoides ssp. sinensis are more adaptable to lower soil moisture. In contrast, male plants are much more sensitive to changes in soil moisture.