长期放牧干扰对荒漠草原优势种银灰旋花解剖性状的影响OA

To investigate how anatomical traits of roots,stems,and leaves of the dominant desert steppe species Convolvulus ammannii respond to long-term grazing at different intensities,and to explore its functional trade-off strategy,this study was conducted at long-term experimental grazing plots with a 19-year grazing history(since 2004)in the desert steppe of Siziwang Banner.Paraffin sections of roots,stems,and leaves were prepared,and their anatomical traits were quantified.Four grazing intensity levels were established in the study area:ungrazed control(CK),light grazing(LG),moderate grazing(MG),and heavy grazing(HG).Grazing enhanced the development of xylem in both roots and stems of C.ammannii.Under heavy grazing,the proportion of root xylem area in the cross-section increased by 15%compared with the control,whereas under light grazing,stem cuticle thickness increased by 8%.Leaf anatomical traits responded differentially to grazing intensity,with palisade tissue thickness increasing by 11%under light grazing(LG).Notably,the anatomical structures of roots,stems,and leaves were highly coordinated:synchronized reinforcement of vascular tissues and cuticle thickening jointly ensured resource transport and enhanced resistance to herbivory,reflecting an integrated strategy that balances resource allocation and defense investment.Long-term grazing disturbance altered the anatomy of vegetative organ in C.amman-nii,and organ-specific structural adjustments may underlie its response to environmental change.This study provides anatomical evidence for the adaptive responses of desert steppe plants to long-term grazing disturbance and offers insights into the ecological adaptation mechanisms of desert steppe ecosystems.