| Desertification is an important environmental problem which threats to the safety and survival of human beings.Psammophyte has played an important role in the process of governing the Desertification.In the recent years,many studies focused on the morphological anatomical structure,physiological ecology,genetic diversity,and adaptive strategy,however,no enough attention was paid to the nutrient utilization strategies of psammophyte.Nutrient resorption is one of the most important nutrient conservation strategies that can ensure nutrients available for future plant growth and allow plants to reduce their dependence on soil nutrient availability.Therefore,based on the national conditions of the Desertification,in this study,we set up sampling sites in the three typical deserts in north China and the resorption efficiencies of N,P,K,Ca,Mg and Na,and morphological traits in dominant psammophyte were measured to reveal the nutrient utilization strategies of psammophyte in poor soil and water restrictions of desert environment and provide a certain basis for the governance of desertification.The main results are as follows:(1)Revealed the nutrient concentrations of psammophyte in different seasons.The average nutrient concentrations of psammophytes were 27.42 mg g-1 for N;3.68 mg g-1 for P;17.02 mg g-1 for K;8.98 mg g-1 for Ca;11.07 mg g-1 for Mg;and 11.59 mg g-1 for Na in green leaves.The average nutrient concentrations of psammophytes were 15.70 mg g-1 for N;1.94 mg g-1 for P;10.78.mg g-1 for K;11.55 mg g-1 for Ca;16.78 mg g-1 for Mg;and 15.41 mg g-1 for Na mg g-1 in senescent leaves.(2)Clarified the N,P,K,Ca,Mg and Na resorption efficiency of psammophyte.The average REs of N,P,K,Ca,Mg and Na of the psammophyte were 43.23%,44.23%,41.07%;-77.47%,-60.07%;and-113.13%,respectively.(3)Revealed the correlation among the different leaf traits of psammophyte.There was no significant correlation between LDMC and SLA in all species.Among different functional groups,there was significant negative correlation between LDMC and SLA in succulents and no-succulents,respecially.There was no significant correlation between LWC and SLA in all species.Among different functional groups,there was significant negative correlation between LWC and SLA in no-succulents,and there was no significant correlation between LWC and SLA in succulents.(4)Revealed the correlation between the leaf traits and leaf nutrient concentrations.There was significant positive correlation between the leaf content of N and P and SLA in all species.There was no significant correlation between the content of leaf Ca and SLA in all species.There was significant negative correlation between the leaf content of Mg and Na and SLA in all species.There was significant nonlinear correlation between the leaf content of K and SLA in all species.(5)By fitting the allometric equations([nutrient]senescent = A([nutrient]green)B),revealed the changing of resorption efficiency with increasing of green leaf nutrients.The values of B(N)and B(P)greater than 1 suggested NRE and PRE decreased with an increase of green leaf nutrient concentrations;The values of B(Ca)and B(Na)smaller than 1 suggested CaRE and NaRE increased with an increase of green leaf nutrient concentrations;However,the B values of K and Mg were not significant difference between 1,which suggested no relationship between KRE and MgRE with nutrient concentrations in green leaves.(6)Illustrated the coupling correlation among the six elements of psammophyte.Positive correlations were found between N and P,Ca and Mg in green leaves,senescent leaves and resorption efficiency,respectively.Psammophyte played an important role in the desert ecosystem and the process of controling land desertification.These results are of great value for further research on the survival strategy of psammophyte in water restrictions and nutrient limitation desert environment.We hope there will be more in-depth study to maintain the stability of desert ecosystem. |
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