盐胁迫对刺榆种子萌发及幼苗生理特征的影响

为了研究刺榆种子及幼苗对盐胁迫的响应，采用培养皿纸上发芽法进行种子萌发并采用盆栽法进行幼苗培养，测定刺榆种子在不同浓度NaCl、Na2SO4、Na2CO3和NaHCO3处理下的发芽率、发芽势、发芽指数、活力指数、相对盐害率，及幼苗丙二醛（malondialdehyde，MDA）、超氧化物歧化酶（superoxide dismutase，SOD）及过氧化物酶（peroxidase，POD）变化规律。结果显示：①在试验设置盐浓度范围内，刺榆种子在NaCl＜30 mmol·L-1、Na2CO3＜10 mmol·L-1、Na2SO4＜20 mmol·L-1、NaHCO3＜20 mmol·L-1的盐胁迫下能够正常发芽，碱性盐（NaHCO3和Na2CO3）的危害大于中性盐（NaCl和Na2SO4）。②刺榆种子的相对盐害率均为正值，4种盐均存在不同程度的种子萌发抑制，不同种类盐分对刺榆种子萌发抑制表现为NaCl＜Na2SO4＜NaHCO3＜Na2CO3。③幼苗生长中，不同处理幼苗叶片内MDA含量呈逐渐上升的趋势，SOD活性和POD活性随浓度的增加呈先升高后降低的趋势。但当NaCl＜30 mmol·L-1、Na2CO3＜10 mmol·L-1、Na2SO4＜10 mmol·L-1、NaHCO3＜20 mmol·L-1时，刺榆幼苗内MDA含量和保护酶活性未发生显著变化。研究表明刺榆种子萌发与幼苗生长对低浓度盐环境具有一定的耐受性，高浓度盐环境会使种子丧失发芽能力阻碍幼苗生长。结果为刺榆在盐碱地的种植和推广提供理论依据。

Effects of Salt Stress on Seed Germination and Seedling Physiological Characteristics of Hemiptelea davidii

In order to study the response of Hemiptelea davidii seeds and seedlings to salt stress, seed germination of H. davidii was carried out on the petri dish and the seedling culture was carried out by pot experiment. Germination rate, germination potential, germination index, vigor index, relative salt damage rate of H. davidii seed were tested under treatments with NaCl、Na2SO4、Na2CO3 and NaHCO3, as well as malondialdehyde (MDA), superoxide dismutase (SOD) and peroxidase (POD) of H. davidii seedlings. The results showed that：① Under salt concentration range of present work, the seeds of H. davidii can germinate normally under the salt stress treatments of NaCl concentration <30 mmol·L-1, Na2CO3 concentration <10 mmol·L-1, Na2SO4 concentration <20 mmol·L-1 and NaHCO3 concentration <20 mmol·L-1. NaHCO3 and Na2CO3 were more harmful than neutral salts of NaCl and Na2SO4. ②The relative salt damage rate of H. davidii seeds was all greater than 0. The four salts all inhibited seed germination, but the extent was different and showed a tendency of NaCl