摘要
以盆栽大豆为材料,设置不同程度的土壤盐分(NaCl)、干旱及旱盐组合处理,然后测定各处理大豆植株的株高、生物量、光合作用指标以及植株的水分状况和Na^+、K^+含量,探索干旱条件下土壤盐分对大豆生长的影响及可能机制。结果表明:干旱和盐胁迫均可导致大豆叶片的净光合速率降低和生长量的减少,干旱还导致光合机构的严重损伤。但是,干旱和适量土壤盐分(100~150 mmol·L^(-1)NaCl)组合处理的大豆植株,其生长量、净光合速率和PSⅡ最大光化学效率都显著高于单一干旱处理。同时,旱盐组合处理的大豆叶片RWC、Na^+含量也高于单一干旱处理,水势和渗透势低于后者,且叶片Na^+含量与其渗透势降低显著相关。综合分析表明,在干旱条件下,土壤适量NaCl的存在使大豆能够吸收和积累更多Na^+等盐离子作为渗透调节物质,来降低渗透势、提高吸水能力,以改善植株的水分状况和光合性能,保持植株较高的生长速率,即土壤中适量盐分(NaCl)的存在可减轻干旱对大豆的负效应。
The impact of soil salinity on the growth of soybean plants and the possible mechanisms in association with the impact was investigated.The investigation involved the measurement of effects of combined drought and salinity stresses on the soybean seedlings.The growth and photosynthetic rate,chlorophyll fluorescence parameters,water status and the K^＋ and Na^＋content in the stressed soybean seedlings.The results showed that,under drought or salt stress,the growth of the seedlings was significantly inhibited,leaf net photosynthesis reduced,resulting in serious injury in the photosynthetic apparatus.However,the parameters like the net photosynthetic rate,maximum quantum efficiency of PhotosystemⅡ and biomass were significantly higher in seedlings subjected to combined stresses of drought and moderate soil salinity than to single drought stress.In addition,the relative water and content and Na^＋ content was also significantly higher,but the water and osmotic potentials of the plants subjected to combined stresses of drought and moderate soil salinity than to single drought stress,with the decline of the tissue osmotic potential being closely correlated to the Na^＋ content.This may suggest that under drought conditions,moderate salt stress in the soil could force the soybean seedlings to absorb and accumulate more Na^＋ ions as osmolytes,so that the tissue osmotic potential being reduced and suction force for water absorption in plants being enhanced,which was conducive to soybean plants maintain higher water content,maintain a relatively higher rate of photosynthesis and growth.In other words,the presence of moderate NaCl in soil might effectively mitigate the negative effects of drought on the growth of soybean.
出处
《大豆科学》
CAS
CSCD
北大核心
2017年第6期921-926,共6页
Soybean Science
基金
国家自然科学青年基金(31601994)
关键词
旱盐组合胁迫
干旱
光合作用
生长
大豆
Combined stresses of drought and salinity
Drought
Photosynthesis
Growth
Soybean
