硅对NaCl胁迫下甜瓜种子萌发及幼苗生长的影响

Effects of exogenous silicon on melon seed germination and the growth of seedlings under NaCl stress

为明确硅（silicon,Si）对盐胁迫的缓解作用,以＂雪梨一号＂和＂朗秦银蜜＂两个耐盐性不同的甜瓜品种为材料,在125mmol/L NaCl胁迫下,研究了不同浓度外源Si对甜瓜种子萌发和幼苗生长的影响。结果表明,NaCl胁迫显著抑制了甜瓜种子萌发,0.50~1.00mmol/L外源Si处理较对照能显著提高种子的发芽率、发芽势、发芽指数、α-淀粉酶活性及吸水率,其中两个品种的种子均以0.75mmol/L外源Si处理效果最好;NaCl胁迫下,0.25~1.00mmol/L外源Si处理后,甜瓜幼苗的株高、叶面积、叶绿素含量、地上部分干重和根系干重较对照显著提高,其中＂朗秦银蜜＂和＂雪梨一号＂幼苗分别以0.50和0.75 mmol/L外源Si处理效果最好。研究表明,0.25~1.00mmol/L外源Si能促进NaCl胁迫下种子吸水和α-淀粉酶活性的提高来促进种子萌发,通过提高NaCl胁迫下幼苗叶绿素含量维持较高的光合能力促进幼苗生长,缓解盐胁迫对甜瓜种子和幼苗的伤害,外源Si浓度超过1.25mmol/L时对盐胁迫没有缓解效应。

The of two melon mmol/L NaC1 effects of exogenous silicon on the growth of melon under salt stress were investigated. Seedlings cultivars （Xueli No. 1 and Longqinyinmi） with different salt tolerance were grown with 125 stress Exposure to 125 mmol/L NaC1 stress significantly inhibited melon seed germination. Compared with control, treatments with 0.5--1.0 mmol/L exogenous silicon significantly increased seed ger- ruination rate, treatment with ge 0. rmination energy, germination index, alpha-amylase activity and water absorption and the 75 mmol/L exogenous silicon performed best. In additio mmol/L silicon exposed to 125 mmol/L NaC1 had significantly increased n, pl melon seedlings with 0.25--1.00 ant height, leaf area, chlorophyll content, shoot dry weight and root dry weight, compared to controls. Treatment with 0.50 mmol/L was opti mal for Longqinyinmi, while 0.75 mmol/L gave best results for Xueli No. 1. These results indicate that exoge nous silicon concentration from O. 50 mmol/L to 0. 75 mmol/L can promote melon seed germination by enhan cing alpha-amylase activity and water absorption, and promote seedling growth by increasing chlorophyll con tent and photosynthesis capacity under salt stress. When the silicon concentration was more than 1.25 mmol/ L, there was no effect on the seed germination and growth of seedlings under salt stress.