聚乙二醇(PEG)模拟干旱胁迫对干旱河谷5种木蓝种子萌发的影响

Effect of Polyethylene Glycol (PEG) Simulated Drought Stress on Seed Germination of Five Species of Indigofera L. from Dry Valleys

以川西干旱河谷地区的5种木蓝属植物的种子为材料,观测其形态特征以及聚乙二醇(PEG-6000)模拟干旱胁迫对种子萌发的影响.实验结果表明,供试木蓝属植物种子的物理特征(大小、千粒重)与萌发特性之间无显著相关性,而种子硬实率与发芽率则显著相关;不同浓度的PEG胁迫对种子的萌发均有一定的延缓作用,并且种子的发芽率、发芽势和发芽指数均随胁迫强度的增加呈现下降趋势。综合比较5种木蓝植物种子的抗旱性,在PEG浓度低于150g/L的轻度干旱胁迫下抗旱性由强到弱依次为:刺序木蓝>河北木蓝≈灰色木蓝≈四川木蓝>多花木蓝;与采自茂县岷江河谷的刺序木蓝相比,来源于泸定大渡河河谷的刺序木蓝的种子萌发对土壤水分的要求较低,并且相同水分条件下后者发芽率、发芽势和发芽指数也显著高于前者,这可能与各自的种源地在气候、水分及土壤条件上的差异有关.

Using the seeds of five species of lndigofera L. （Leguminosae-Papilionoideae DC.） collected from dry valleys in western Sichuan, China as test material, the effect of polyethylene glycol （PEG-6000） simulated drought stress on their germination was studied. The results indicated that there was no obvious relationship between seed germination property and its physical characters （such as seed size, thousand seed weight） under drought stress, but seed germination rate is obviously related to its hard seed percentage. The results also showed that PEG solution of different concentration could retard the germination of seeds in different strength, and the germination rate, germination potential and germination index all decreased with increasing of PEG concentration. The drought-resistance order of five species under lower level drought stress at 50-150 g/L PEG solution was L silvestrii 〉 L bungeana ~ 1. cinerascens ~ 1. szechuensis 〉 1. amblyantha. The seed germination of/. silvestrii from Daduhe River valley （Luding） requires lower water condition than that from Min River valley （Maoxian）, and the former＇s germination rate, germination potential and germination index all are obviously higher than latter in the same water level. This might be due to the differences of microenvironment （such as climate, rainfall, soil etc） in the two places. Fig 3, Tab 5, Ref25