模拟水分胁迫对不同种源麻楝种子萌发能力的影响

Effect of Water Stress Simulated by PEG on Germination Ability of Chukrasia tabularis Seeds from Different Provenances

以麻楝6个种源种子为试验材料,用不同浓度的聚乙二醇(PEG)溶液模拟干旱胁迫,探讨干旱胁迫对种子发芽率、发芽势、发芽指数、活力指数以及幼苗苗高和胚根长及根苗比的影响,为麻楝的引种和推广种植提供依据。结果显示:(1)不同水势胁迫处理均降低了麻楝种子的发芽率和发芽势,当水势为-0.40MPa时延缓了种子萌发进程;种子的发芽率、发芽势、发芽指数和活力指数均随干旱胁迫强度的增加呈明显下降的趋势;当胁迫水势为-0.86MPa时,干旱胁迫处理的种子在试验结束时仍未能萌发,即-0.86MPa是麻楝种子萌发的临界水势。(2)当胁迫水势高于-0.40MPa时,麻楝幼苗的胚根长度与对照组差异不显著且长于对照组,说明高于-0.40MPa的水势有利于麻楝种子胚根的生长;麻楝幼苗苗高生长则是随着PEG浓度的升高而逐渐减缓。(3)适当的干旱胁迫可以增大各种源麻楝幼苗根苗比,且在胁迫水势高于-0.20MPa时都达到最大值。研究表明,麻楝种子具有一定的抗干旱胁迫的萌发能力,并以来自缅甸的Khin Aye Pale和泰国的Phu Wiang材料较强,来源于中国三亚和马来西亚Ulu Tranan的较弱。

By taking six provenance seeds of species Chukrasia tabularis A. Juss as the test material and through simulating drought stress with different concentrations and osmotic potential of polyethylene gly- col （PEG-6000）, the effects of drought stress on germination rate, germinating potential, radicals, hypocot- yls length, germination index, viability index and ratio of root to shoot were investigated. The results showed that： （1）PEG retarded the proceeding of seeds germination of C. tabularis and the germination percentage, germina- tion index and seed viability index were all showed the downtrend obviously with increasing concentration of water stress;The seeds treated with -0.86 MPa water potential of PEG did not germinate at all after the experiment fin- ished. So this indicated -0.86 MPa water potential was the threshold for the germination of C. tabularis seeds. （2） When the water stress above -0.40 MPa,C. tabularis seedling radicale length was no significant difference and e- ven longer than that of control group. The findings revealed that the water potential higher than -0.40 MPa was beneficial to the growth of the radicals of C. tabularis seeds;the growth of C. tabularis seedlings de- creased with arising PEG concentrations. （3）The ratio of root to shoot as an important indicator of sound seedling,appropriate water stress could increase the ratio of root to shoot. When the water stress higher than -0.20 MPa,the ratio of root to shoot of all kinds provenance have reached the maximum. In Summa- ry,C. tabularis seed can germinate under appropriate drought stress. The seeds from Khin Aye Pale and Phu Wiang is better than that from Sanya and Ulu Tranan.