Abstract
The relationship between plant water status and osmotic adjustment was compared between Artemisia ordosica and Caragana korshinskii growing in Mu Us Sandy land, China, in 2008, 2009 and 2010. We studied plant water relations using the p-v curve method and detected several osmolytes including soluble sugars, proline and betaines in leaves of them at pre-dawn and midday. We also measured diurnal changes in leaf water potential and sugar content of both species. The turgor maintenance potential in A. ordosica at midday was higher than that at predawn. Conversely, there was no difference between predawn and midday in C. korsinskii. The total sugar content in A. ordosica at midday was higher than that at predawn, whereas the sugar content in C. korshinskii at midday was not different from that at predawn. In diurnal changes A. ordosica had negative correlation of sucrose content with leaf water potential, whereas no correlation in C. korshinskii. It is concluded that A. ordosica has an ability of osmotic adjustment to diurnal changes in plant water status using sucrose as one of possible osmolytes.
