遮阴与种植密度对紫萼光合生理的影响OA

[Objective]This study aims to explore the photosynthetic physiological response mechanisms of Hosta ventricosa(Salisb.)Stearn under different light conditions and planting densities,in order to provide theoretical and practical guidance for its understory cultivation and landscape application.[Method]Three shading treatments were set:30%-35%transmittance(L1),45%-50%(L2),and 60%-70%(L3),along with three planting densities:10 cm×10 cm(D1),12 cm×12 cm(D2),and 21 cm×21 cm(D3).By analyzing photosynthetic gas exchange parameters,chlorophyll fluorescence,chlorophyll content,osmotic adjustment substances,antioxidant enzyme activities,and morphological indicators of Hosta ventricosa leaves,we investigated the effects of shading,planting density,and their interaction on the growth and photosynthetic adaptation of the plant.[Result](1)In terms of physiological adaptability,H.ventricosa exhibited optimal photosynthetic performance under moderate shading(L2,45%-50%light transmittance),with the net photosynthetic rate reaching 5.55 μmol/(m²·s).It enhanced low-light adaptation and oxidative stress resistance by increasing total chlorophyll content,reducing the chlorophyll a/b ratio(1.91-2.15),and activating the antioxidant enzyme system(e.g.,POD activity reached 388.4 U/g FW).(2)In cultivation mode,moderate density(D2)combined with moderate shading(L2)significantly improved water-use efficiency(up to 8.73 μmol/mmol)and maximized biomass accumulation.(3)Two-factor analysis showed a significant interaction between shading and density,with the combination of moderate shading and moderate density(L2+D2)most effectively promoting the overall optimization of photosynthetic physiological function and morphological development.[Conclusion]The response of H.ventricosa to shading and planting density demonstrates clear physiological plasticity and resource trade-off characteristics.The results indicate that the combination of moderate shading(L2)and moderate density(D2)(L2+D2)can effectively coordinate light distribution within the population,alleviate photoinhibition,enhance antioxidant defense,and improve water-use efficiency.This represents a superior cultivation configuration for achieving both high-quality individual growth and stable population yield.The findings provide direct guidance for the scientific cultivation of H.ventricosa in understory economy,multi-layer landscape construction,and ecological restoration in karst regions.