光周期对黄瓜幼苗形态、光合特性及碳水化合物含量的影响

为探究光周期对黄瓜幼苗形态、光合特性及碳水化合物含量的影响，在光强为250 μmol/（m²·s）的白光下，设置光周期为8 h/16 h、12 h/12 h、16 h/8 h和20 h/4 h共4个处理，比较各处理对黄瓜幼苗的影响。结果表明：不同光周期处理后的黄瓜幼苗形态差异较大，其株高、茎粗、鲜重、干重与叶面积均发生显著性差异，12 h/12 h处理下株高、茎粗和总叶面积均显著优于其余处理；随着光周期的增加，叶片各组织厚度增加，Rubisco酶活性呈现下降趋势，8 h/16 h处理较16 h/8 h与20 h/4 h处理显著增加66.23%和82.86%；黄瓜幼苗总氮含量随着光周期的增加呈现显著下降趋势；12 h/12 h处理下总碳含量显著高于8 h/16 h和20 h/4 h；12 h/12 h和16 h/8 h处理的淀粉含量显著高于其余处理。综上，12 h/12 h处理为黄瓜幼苗生长的最适宜光照周期。该研究结果可为植物工厂化育苗及设施内补光提供依据和参考。

Effects of photoperiods on morphology, photosynthetic characters and carbohydrate of cucumber seedlings

The study was to investigate the effect of photoperiod on morphology， photosynthetic characteristics and carbohydrate content of cucumber seedlings. Under a light intensity of 250 μmol/（m²·s）， four treatments of photoperiods of 8 h/16 h， 12 h/12 h， 16 h/8 h and 20 h/4 h were set to compare the effects of each treatment on cucumber seedlings. The results showed that： The morphological differences of cucumber seedlings after different photoperiod treatments were significant. Their plant height， stem thickness， fresh weight， dry weight and leaf area were all significantly different， and the plant height， stem thickness， and total leaf area under the 12 h/12 h treatment were significantly better than the other treatments. As the photoperiod increases， the thickness of various tissues in the leaves increased， and the activity of Rubisco showed a decreasing trend. The 8 h/16 h treatment significantly increased by 66.23% and 82.86% compared to the 20 h/4 h treatments. The total nitrogen content of cucumber seedlings showed a significant decreasing trend with the increase of photoperiod. The total carbon content under 12 h/12 h treatment was significantly higher than that under 8 h/16 h and 20 h/4 h treatments.The starch content in 12 h/12 h and 16 h/8 h treatments was significantly higher than the other treatments. Taken together， the 12 h/12 h treatment was the optimum photoperiod for cucumber seedling growth. The study can provide a basis and reference for plant factory nursery and supplemental light in facilities.