Effects of desertification degree on the appearance traits and reproductive strategies of Astragalus bhotanensisin in reseeding grassland
[Objective]To provide technical support for desertification control,grassland revitalization,and the construction of"four reservoirs",aimed at enhancing the ecological productivity of desertified alpine meadows on the Qinghai Tibet Plateau.[Method]The seeds of Astragalus bhotanensis,a leguminous plant,were reseeded in grass-lands with four levels of desertification(non sandy,light,moderate and heavy desertification).Key indicators such as component traits,biomass structure,and reproductive allocation were measured to examine differences in appearance traits and reproductive strategies of reseeded A.bhotanensis.[Result]The level of desertification significantly influ-enced the traits of leaves,stems,roots,and flowers of A.bhotanensis(P<0.05).The number of branches,root length,root number,and root volume increased significantly with desertification severity,while the plant height de-creased with the desertification degree(P<0.05).Moderate desertification significantly enhanced compound leaf number,stem length,stem diameter,and root diameter(P<0.05),resulting in the highest absolute biomass for leaves,stems,roots,and flowers.Severe desertification cincreased the number of small leaves but inhibited stem length.The degree of desertification significantly affected panicle,flower,fruit,and seed numbers of A.bhotanensis(P<0.05),but had no significant effect on pod length and seed thousand grain weight.Reproductive and sexual indica-tors of A.bhotanensis were also significantly affected by desertification(P<0.05).Clone reproductive ability de-creased with the desertification degree.Mild desertification yielded the highest reproductive allocation and reproduc-tive index,moderate desertification achieved the highest reproductive efficiency index,and severe desertification re-corded the highest cloning efficiency index.[Conclusion]A.bhotanensis could form an external plant cluster struc-ture,growth mode,and reproductive strategy corresponding to desertification degrees by morphological plasticity,bio-mass allocation,and reproductive balance.As a sand-resistant and sand-stabilizing leguminous grass,A.bhotanensis demonstrates significant potential for vegetation restoration and reconstruction of moderately to severely desertified grasslands.
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