干旱胁迫对沙地柏幼苗生长及生理特性的影响OA

To investigate the effects of drought stress on the growth and physiology of Juniperus sabina seedlings,one-year-old cuttings were used as experimental material.Four treatments were established:nor-mal watering(75%-80%of field capacity),mild drought(55%-60%of field capacity),moderate drought(35%-40%of field capacity),and severe drought(15%-20%of field capacity).Changes in growth and physiological indicators were compared across treatments.Results indicated that as drought stress intensified,growth and photosynthetic parameters of J.sabina seedlings showed a significant down-ward trend(decreases in plant height,stem diameter increment,biomass,net photosynthetic rate,etc.,while root-to-shoot ratio increased and chlorophyll content first rose then fell),and membrane damage in-dicators(MDA)progressively increased.Concurrently,seedling concentrations of osmotic regulators(pro-line,soluble sugars,etc.)and antioxidant enzyme activities(SOD,POD,etc.)generally increased,exhibi-ting organ-specific variations.Correlation analysis revealed positive correlations between growth and photo-synthetic indices,negative correlations between membrane damage indices and growth∕photosynthesis indi-ces,and negative correlations between osmotic regulators∕antioxidant enzymes and membrane damage indi-ces.In summary,J.sabina seedlings resist drought through multifaceted synergistic actions:on one hand,they adjust growth and photosynthetic strategies by slowing shoot height and biomass accumulation rates,reducing net photosynthetic rates,and minimizing energy dissipation,while adapting to drought conditions via increased root-to-shoot ratios and chlorophyll content that initially rises then declines;the other hand,they activate defense mechanisms by altering water accumulation and distribution patterns,enhancing SOD,POD,and CAT activities,and proactively accumulating osmotic regulators to counter drought stress.