种子萌发期4种植物对干旱胁迫的响应及其抗旱性评价研究

用不同浓度PEG-6000的1/2Hoagland溶液模拟干旱胁迫条件,对沙枣、柠条、杠柳、白蜡4种植物种子的总萌发率、幼苗鲜重、活力指数进行研究.结果表明:(1)随着干旱胁迫程度的加剧4种植物种子的总萌发率、幼苗鲜重、活力指数呈下降趋势,且白蜡下降幅度最大,但柠条、沙枣、杠柳的抗旱指数显著高于白蜡;(2)4种植物种子的逐日萌发率和胚根日变化表明:低浓度PEG-6000对柠条和杠柳的种子萌发具有较好的诱发作用,白蜡和杠柳种子萌发比较集中,沙枣和柠条相对比较分散;沙枣、柠条和白蜡胚根生长呈线性增长,而杠柳呈指数式增长;(3)采用隶属函数法对干旱胁迫下4种植物的相对萌发率、相对鲜重、抗旱指数、相对活力指数进行综合评价的结果显示,4种植物种子萌发阶段的抗旱性次序为:柠条>沙枣>杠柳>白蜡.

Response to Droughty Stresses and Drought-resistances Evaluation of Four Species during Seed Germination

The total seed germination rates,seedling fresh weights and vigor indexes of four species,Elaeagnus angustifolia L.,Caragana korshinskii Kom.,Periploca sepium Bge and Fraxinus velutina Torr,were studied under droughty circumstances simulated with 1/2 Hoagland solution having different concentrations of PEG-6000.It was shown that(1) as the drought become intensified the total seed germination rates,seedling fresh weights and vigor indexes of four species tended to decline and those of F.velutina Torr presented the largest decrement,but the drought-resistance indexes of E.angustifolia L.,C.korshinskii Kom.,P.sepium Bge were significantly higher than that of F.velutina Torr;(2) the diurnal germination rates and radicel variations of the four species indicated that PEG-6000 exerted good inductive effect on the seed germinations of C.korshinskii Kom.,P.sepium Bge at low concentration,the seeds of F.velutina Torr and P.sepium Bge germinated in a concentrative manner and the seeds of E.angustifolia L.,C.korshinskii Kom.Germinated in a dispersed manner;the radicels of E.angustifolia L.,C.korshinskii Kom.and F.velutina Torr appeared to grow linearly and the radicels of P.sepium Bge appeared to grow exponentially;(3) the comprehensive evaluation of the relative seed germination rates,relative seedling fresh weights and relative vigor indexes of four species by membership function method indicated that the drought resistances of the four species decreased in the order of C.korshinskii Kom.>E.angustifolia L.>P.sepium Bge>F.velutina Torr.