Meng Chuang, Xue Zhan-Jun, Yang Ji-Long, Li Shou-Mian, Gao Zhi-Kui
College of Horticulture, Hebei Agricultural University, Baoding 071001, Hebei, China.
Ying Yong Sheng Tai Xue Bao. 2021 Jan;32(1):222-230. doi: 10.13287/j.1001-9332.202101.024.
In order to clarify the effects of foliar spraying the solution with low concentration NaCl on the growth and matter accumulation of vegetables under the temperature-regulated solar greenhouse, we carried out an experiment on cucumber seedlings with two cotyledons, under two tempera-ture regimes and four concentrations of NaCl. Low-medium temperature zone (L) and medium-high temperature zone (H) were set by low tunnel with plastic film in the greenhouse. The solutions with different concentrations of NaCl, 0 mmol·L (L and H), 5 mmol·L (L and H), 10 mmol·L (L and H) and 15 mmol·L (L and H), were sprayed every day to the cucumber seedlings. The seedling growth, plant biomass, nutrient accumulation and photosynthetic gas exchange parameters of cucumber seedlings were measured at the 21th day of spraying treatment. Compared with the control groups (L and H), NaCl spraying significantly increased dry matter and plant water content by 38.6% (L)-50.2% (L) and 20.8% (L)-52.2% (L) in L zone, 8.9% (H)-23.3% (H) and 8.7% (H)-10.1% (H) in H zone, respectively. The treatment of 10 mmol·L NaCl (L and H) under both temperature regimes increased dry matter accumulation and plant water content than other treatments. Nevertheless, the highest normalized strong seedling index (SI) with the highest stomatal conductance () and photosynthetic rate () was only found in L treatment. L treatment promoted foliar expansion much more than H treatment. In addition, foliar spraying NaCl with concentrations from 5 mmol·L to 10 mmol·L under both temperature regimes significantly increased the accumulation of soluble sugar, free amino acids and soluble protein, which were preferentially allocated to the stem or root of cucumber seedlings. Results of two-way ANOVA showed significant effects of both temperature and NaCl concentration on dry biomass, leaf area, , plant water content, SI, and free amino acid content. On the contrary, there were significant interactions between temperature and NaCl concentration in affecting plant water content, SI, and free amino acid content (except leaf). In conclusion, foliar spraying with 5-10 mmol L NaCl could promote growth and physiological indices of cucumber seedlings, with the effect being higher under low temperature regime. More importantly, foliar spraying of proper concentration (L and H) of NaCl could stimulate biomass accumulation more than water retention in cucumber seedlings, which would provide a relevant breeding target for high water-use efficiency in cucumber.
为了阐明在温度调控的日光温室内，对蔬菜叶面喷施低浓度氯化钠溶液对其生长和物质积累的影响，我们以两片子叶的黄瓜幼苗为材料，在两种温度条件和四种氯化钠浓度下开展了实验。温室内通过塑料薄膜搭建的小拱棚设置了低温区（L）和中高温区（H）。每天向黄瓜幼苗喷施不同浓度的氯化钠溶液，浓度分别为0 mmol·L（L和H）、5 mmol·L（L和H）、10 mmol·L（L和H）和15 mmol·L（L和H）。在喷施处理的第21天，测定黄瓜幼苗的生长、植株生物量、养分积累和光合气体交换参数。与对照组（L和H）相比，喷施氯化钠显著提高了L区黄瓜幼苗的干物质和植株含水量，分别提高了38.6%（L）-50.2%（L）和20.8%（L）-52.2%（L）；在H区分别提高了8.9%（H）-23.3%（H）和8.7%（H）-10.1%（H）。两种温度条件下，10 mmol·L氯化钠处理（L和H）的干物质积累和植株含水量均高于其他处理。然而，最高的标准化壮苗指数（SI）以及最高的气孔导度（）和光合速率（）仅在L处理中出现。L处理比H处理更能促进叶片扩展。此外，两种温度条件下，叶面喷施浓度为5 mmol·L至10 mmol·L的氯化钠显著增加了可溶性糖、游离氨基酸和可溶性蛋白质的积累，这些物质优先分配到黄瓜幼苗的茎或根中。双向方差分析结果表明，温度和氯化钠浓度对干生物量、叶面积、、植株含水量、SI、和游离氨基酸含量均有显著影响。相反，温度和氯化钠浓度在影响植株含水量、SI、和游离氨基酸含量（除叶片外）方面存在显著交互作用。总之，叶面喷施5-10 mmol L氯化钠可促进黄瓜幼苗的生长和生理指标，在低温条件下效果更佳。更重要的是，叶面喷施适当浓度（L和H）的氯化钠对黄瓜幼苗生物量积累的刺激作用大于保水作用，这将为黄瓜高水分利用效率提供一个相关的育种目标。
