罗马苜蓿种子休眠、萌发特性及苗期抗旱性能研究

The Study on Medicago falcata var. romanica Seed Dormancy,Germination Characteristics and Seedling Drought Resistance

【目的】研究不同处理方法对罗马苜蓿萌发率的影响,以及在不同干旱胁迫下幼苗根、茎、叶中渗透物质的变化。【方法】采用98%浓硫酸浸泡、-18℃低温、85℃高温水浴、机械摩擦、液氮浸泡等方法对种子进行处理;同时进行盆栽干旱胁迫试验,测定不同干旱胁迫下根、茎、叶的可溶性糖、可溶性蛋白质、脯氨酸含量的变化。【结果】除低温处理组外,其他各处理均能显著提高种子发芽率(P<0.05),其中,机械处理种子发芽率最高,较对照组10%提高了9.5倍。随着干旱胁迫强度增加,罗马苜蓿各器官可溶性糖、可溶性蛋白质、脯氨酸渗透物质积累量显著增加(P<0.05)。【结论】罗马苜蓿存在大量硬实种子,除低温处理外,浓硫酸浸泡、高温水浴、机械摩擦和液氮浸泡处理均能显著消除种子硬实(P<0.05);罗马苜蓿在苗期就可通过产生渗透调节物质来应对干旱胁迫,具有较好的抗旱性能。

[ Objective ] This study aims to research the germination rate of Medicagofalcata var. romani- ca under different treatments and its drought tolerance at seedling stage. [ Method ] Different methods such as 98% H2SO4 soaking （ 1, 2, 3, 5 min）, the low temperature （ - 18℃, 5 min）, high temperature water （ 85 ℃, 7 d）, sandpaper polishing, liquid nitrogen soaking （ 1,5 min） and control group were used to handle seeds and then measure their germination rate. At the same time, pot experiment was conducted in the green- house to measure the changes of soluble sugar, soluble protein and proline content in roots, stems and leaves under different drought stress. [ Result ] Except the low temperature treatment group, other treatments could significantly improve the seed germination rate （ P 〈 0.05 ）. Among them, the seed germination rate of sand- paper polished seeds was the highest, 9.5 times higher than the control group （ 10% ）. The soluble sugar, soluble protein, and proline were significantly increased with increasing of drought stress （P 〈 0.05 ）. [ Conclusion]There are many hard seeds in M. falcata var. romanica. H2SO4 soaking, high temperature water, sandpaper polishing and liquid nitrogen soaking could eliminate seed dormancy （ P 〈 0.05 ）. Seedlings of M. falcata var. romanica have powerful resistance ability against any drought stress through increasing content of osmoregulation substance.