遮光胁迫下外源NO对盆栽长春花土壤养分含量及幼苗生长特征的影响

为探究遮光胁迫下施加外源NO供体（硝普钠，SNP）对土壤养分变化和长春花（Catharanthus roseus）幼苗生长的影响，设置4种处理（全光照生长为对照、外施SNP、遮光、遮光+外施SNP联合处理），分析盆栽土壤中C、N、P养分含量和土壤理化指标，测定幼苗的株高、节间距、茎直径、叶长、叶宽、叶面积、全株鲜（干）质量。结果表明：遮光和外施NO联合处理下，土壤含水量、土壤pH和土壤有机碳含量显著增加（P<0.05），而土壤中全氮、碱解氮、全磷和速效磷含量增加但不显著，土壤C/N和C/P值升高，且C/N值达到显著水平（P<0.05）；相关性分析结果表明：土壤pH与有机碳含量呈显著正相关性（P<0.05），土壤有机碳含量与株高、叶片鲜质量之间呈显著正相关（P<0.05）。说明施加外源NO能促进遮光胁迫下土壤pH升高，改变土壤中有机碳含量，增加C/N值，改善土壤肥力，促进叶片生长发育，增加长春花的生物量，为长春花的科学平衡施肥和生物碱含量的积累提供一定依据。

Effects of Exogenous NO on Soil Nutrient Content and Seedling Growth Characteristics from Potted Catharanthus roseus under Light-shading Stress

To explore the effect of exogenous NO donor（sodium nitroprusside， SNP） on soil nutrient content and Catharanthus roseus seedlings growth under light-shading stress， four treatments（normal culture， external application of SNP， light-shading treatment and external application of SNP+ shading treatment） were designed， and the change characteristics of C， N， P nutrient contents and physicochemical index from potted soil， and the seedling shoot growth index（plant height， leaf length， leaf width， leaf area， fresh mass and dry mass） were analyzed respectively. The results showed that soil water content， soil pH and soil organic carbon content increased significantly（P<0.05） under the combination of shading stress and exogenous NO， while the contents of total nitrogen， alkali-hydrolyzable nitrogen， total phosphorus and available phosphorus in soil increased but not significantly， and the soil C/N and C/P values reached significant level， and the C/N value increased significantly（P<0.05）； Correlation analysis showed that there was a positive correlation between soil pH value and organic carbon content（P<0.05）， the change of soil organic carbon content was positively correlated with plant height and leaf fresh mass（P<0.05）. It indicated that external application of SNP could promote the increase of soil pH under light-shading stress， change soil organic carbon content， increase C/N value， improve soil fertility， and promote leaf growth and development， then increase the biomass of C. roseus， and provide basis for scientific balanced fertilization and alkaloid content accumulation of C. roseus.