干旱区生态环境知识资源中心

The understanding of the relationship between desertification reversal, a globally significant process, and two fundamental properties of plants, i.e., leaf chlorophyll (Chl) content and photosynthesis, can lead to breakthroughs in research in global environmental change. But much still remains to be known about whether plants acquire adaptive changes during the process of desertification reversal and about their relationships with soil mineral resources. In the present study, leaf total Chl content and photosynthetic characteristics of two common plant species, Pennisetum centrasiaticum Tzvel. and Leymus secalinus (Georgi) Tzvel., were investigated in relation with the soil properties in areas at five different stages of desertification reversal in Southern Mu Us Sandy Land, China. Leaf total Chl content of P. centrasiaticum significantly (P < 0.05) increased by 13.35%, and the net photosynthetic rate (P-n) of L. secalinus increased by 88.8% in the process of desertification reversal. Both P-n of L. secalinus and Chl content of P. centrasiaticum were significantly associated with soil available nitrogen (AN) and phosphorus (AP). However, there was no significant association between P-n of L. secalinus and soil water content (SW) or between leaf Chl content of P. centrasiaticum and SW. Our findings suggest that the availability of N and P in soil could explain the adaptive changes in photosynthesis-related properties of common plant species for different stages of desertification reversal. This further implicates the roles of soil N and P availability in the adaption of plants to environmental changes. Our results also suggest that soil water content may not be a limiting factor for plant adaption when the rainy season overlaps with growing season.