种子超干贮藏对中性盐胁迫下紫花苜蓿生长和抗性的影响

Effects of seed ultra-drying storage on growth and resistance of Medicago sativa seedlings affected by neutral salt stress

采用硅胶干燥法对陇东紫花苜蓿种子进行不同程度的干燥处理,并于室温下贮藏1年后进行盐胁迫沙培试验,以探明种子超干贮藏对植株生长和抗性的影响。结果表明,经适当超干处理并贮藏后,种子出苗率提高53.33%~66.67%,60d时植株叶片数提高14.02%~58.34%,根体积提高36.22%~194.22%,根长提高13.75%~18.66%,可溶性糖含量提高31.5%~36.81%,而MDA含量降至对照的18.09%~74.51%,各处理株高和叶绿素含量与种子含水量间规律性较弱,趋势不明显;轻度干燥处理促进了植株生物量的增加,而含水量的继续下降则降低了生物量;各处理植株的根系活力（4.59%含水量处理除外）和根瘤数与对照比差异不显著或显著低于对照。说明适度含水量的超干贮藏促进了中性盐胁迫下种子的萌发以及植株叶片和根系生长,增强了植株的渗透调节能力并降低了其遭受逆境胁迫的程度,但对根瘤的产生并无促进作用甚至影响了其形成。

In order to make clear the effect of seed ultra-drying to growth and resistance of the resulting seed- lings, Medicago sativa cv. Longdong was used to be differently desiccated with silica gel method, and pot cul- ture with sand and neutral salt stress was conducted after 1 year storage. The result indicated that after moder- ate ultra-drying, seedling emergence, plant leaflet number （60 days）, root volume, root length and soluble sugar content increased 53.33%--66.67%, 14.02%--58.34%, 36.22%--194.22%, 13. 75%-18. 66% and 31.5%--36.81%, respectively, while MDA content decreased to 18.09%--74.51%, compared with the con- trol; no significant tendency was found between shoot height/chlorophyll content and seed moisture content; mild desiccation treatment accelerated plant biomass, while consistent seed moisture content decrease restricted plant biomass; root activity （4.59 % treatment excluded） and nodule number of each treatment were signifi- cantly lower than or with no difference compared with the control, indicating that moderate seed ultra-drying and storage accelerated seedling emergence, leaf and root growth for seedlings grown under neutral salt stress, strengthened plant osmosis regulation and decreased adverse stress, but had no promotion in nodule generation or even affected its formation.