Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： The construction of mathematical models is one of the important methods to estimate shrub biomass. In this study, two desert shrubs, Reaumuria soongarica and Sympegma regelii, commonly found in the piedmont belt of the northern slopes of the mid Kunlun Mountains, were observed in this study. The whole-plant harvesting method was used, plant height (H), canopy area (S) and plant volume (V) were used as the independent variables, and plant above-ground biomass (W1), below-ground biomass (W2) and whole-plant biomass (W3) were used as the dependent variables, to establish function model. The optimal models for biomass estimation of these two desert shrubs were selected based on the largest determination coefficient (R2), the smallest estimated standard deviation (SEE) and significant level (P<0.001). The results showed that the optimal models for biomass estimation of R. soongarica and S. regelii were quadratic function model, except for the whole plant optimal prediction model of S. regelii was linear function model. For R. soongarica, the highest correlation was observed between plant volume (V) and biomass, with R2 ranged from 0.820 to 0.920. For S. regelii, the highest correlation between canopy area (S) and biomass was observed, with R2 ranged from 0.935 to 0.973. The optimal models for biomass estimation of R. soongarica and S. regelii all passed through significance test (P<0.001), with fit rates ranging from 84.1% to 95.6%, and these models could be used for biomass estimation. The results from this study will be very helpful for studying carbon stocks and evaluating carbon sink potential in desert ecosystem.
Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： To construct shelter forests in arid areas, selecting plant species with strong stress tolerance andadaptability is key. By simulating a pot water control experiment with different drought gradients, the ecologicaladaptability of the introduced plant Atriplex canescens and the native plant Tamarix ramosissima willow todrought stress were compared. The results showed that (1) With an increase in drought degree, the water contentin the A. canescens and T. ramosissima leaves reduced gradually, and the water retention capacity, prolinecontent, and relative conductivity gradually increased. The soluble sugar and malondialdehyde contents of A.canescens and T. ramosissima were the maximum in mild and severe drought, respectively, and the increase ratewas greater in T. ramosissima. (2) The POD activity of A. canescens and T. ramosissima increased gradually, andunder severe drought, the percentage increase of T. ramosissima compared with the control wasapproximatelythree times that of A. canescens; SOD activity was greatest under moderate drought, and thepercentage increase in T. ramosissima compared with the control was approximatelyfive times that of A.canescens. The changes in the activity of both enzymes of T. ramosissima were greater than those of A.canescens. (3) The chlorophyll content of A. canescens and T. ramosissima were mildly dry > control > moderatedrought > severe drought, the net photosynthetic rate, transpiration rate, stomatal conductance, and intercellularcarbon dioxide concentration of T. ramosissima gradually decreased, and mild drought slightly promotedchlorophyll and photosynthetic capacity of A. canescens. (4) The correlation and principal component analysisresults indicated that the relationship between the T. ramosissima traits was closer under drought stress, and therelationship between traits and traits was difficult to change in A. canescens, which was relatively conservative.Conclusion: A. canescens is less affected by drought stress, and its drought adaptability is slightly stronger thanthat of T. ramosissima.
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