基质中保水剂浓度对生菜幼苗生长的影响

【目的】添加适量的保水剂,能够促进生菜幼苗的生长。为了了解保水剂对生菜基质育苗的影响,研究最适宜添加的浓度。【方法】在育苗基质中,分别添加质量分数为1‰、2‰、4‰及8‰的保水剂,研究不同浓度保水剂对育苗基质性状及生菜幼苗生长的影响。【结果】随着保水剂浓度的增加,基质的持水量、pH值、电导率(EC值)增大,水分散失速度减缓。基质中添加4‰保水剂的处理显著提升了生菜地上、地下部鲜重及全株干重;显著升高了干物质积累速率(G值)、壮苗指数、根系活力;显著增加了生菜叶片的叶绿素a、b及总含量;显著提升了幼苗净光合速率、蒸腾速率、胞间CO_2浓度、气孔导度。【结论】在生菜穴盘育苗基质中,保水剂的最佳施用量为4‰。

Effect of concentration of water-retaining agent on the growth of lettuce seedlings

Objective]The growth of lettuce seedlings could be promoted by substrate with suitable amount of water-retaining agent.In order to comprehend the effect of water-retaining agent on lettuce seedling and the most suitable concentration of added.Methods]The substrate were respectively added different concentration of 1 per thousand,2 per thousand,4 per thousand and 8 per thousand water-retaining agent,the effects of properties of substrate and growth of lettuce seedling in different concentration water-retaining agent were studied.Results]The results showed that with the increase of water-retaining agent concentration,water holding capacity,pH value and electrical conductivity (EC) were increased,the rate of water loss mitigation was decreased.Treatment of 4 per thousand significantly enhance root fresh weight and dry weight of whole plant dry matter accumulation rate of lettuce seedling;the accumulation rate of dry matter (G value),seedling index,root vigor of treatment were increased significantly;chlorophyll a,b and the total content of lettuce leaf increased significantly;that significantly increased net photosynthetic rate,transpiration rate,inter cellular CO2 concentration and stomatal conductance of lettuce seedling.Conclusion]The optimum concentration of water-retaining agent in lettuce seedlings substrate was 4 per thousand.