摘要
以扁蓿豆(Melilotoides ruthenica)为材料,采用盆栽控水试验,在正常供水(80%田间持水量(FC))、轻度(60%FC)、中度(40%FC)和重度(20%FC)水分胁迫下设置不同的水杨酸浓度(0,0.02,0.1,0.5,2.5mmol.L-1)处理,于初花期对其光合作用、生长特性及干物质产量和饲草品质进行测定,以探讨外源水杨酸对水分胁迫下初花期扁蓿豆的影响。结果表明:干旱降低了扁蓿豆的光合能力、生长特性和饲草产量品质。正常供水下,水杨酸对各指标均无显著影响;轻度水分胁迫下,0.1mmol.L-1水杨酸显著提高叶片光合速率(Pn)、胞间CO2浓度(Ci)(P<0.05),同时显著提高株高和粗脂肪(EE)含量,显著降低气孔限制值(Ls)和中性洗涤纤维(NDF)含量(P<0.05);中度水分胁迫下,0.5mmol.L-1水杨酸显著提高气孔导度(Gs)、Ci、茎粗、一级分枝数、干物质产量、粗灰分(CA)含量以及干物质体外消化率(IVDMD)(P<0.05),显著降低Ls(P<0.05);重度水分胁迫下,0.5mmol.L-1水杨酸显著提高扁蓿豆Pn、水分利用效率(WUE)、株高、干物质产量和IVDMD(P<0.05),同时NDF含量显著降低(P<0.05)。可见,适宜浓度的水杨酸可以改善水分胁迫下初花期扁蓿豆光合作用,提高其干物质产量和饲草品质。
The pot culture experiment was conducted to determine the effects of the different concentrations （0, 0.02, 0.1, 0.5, 2.5 mmol - L-1） of salicylic acid （SA） on photosynthetic characteristics, growth, dry matter yield and quality of forage of Melilotoides ruthenica at the early flowering stage under normal irrigation （80% field capacity）, mild water stress （60% field capacity）, moderate water stress （40% field capacity） and severe water stress （20 % field capacity） in order to understand the effects of exogenous SA on drought tolerance of Melilotoides ruthenica at the early flowering stage. Results showed that water stress decreased photosynthesis, and had nega- tive impact on the growth, yield and quality of forage of Melilotoides ruthenica. Under normal irrigation, salicylic acid didn＇t significantly affect all the indexes. Under mild water stress, 0.1 mmol L-1 salicylic acid significantly increased photosynthetic rate （P.）, intercellular CO2 concentration （Ci）, plant height and ethanol extract （EE） content, but significantly decreased stomatal limitation value （Ls） and neutral detergent fiber （NDF） compared with the control （P〈0. 05）. Under moderate water stress,0. 5 mmol L-1 salicylic acid significantly increased stomatal conductance （G,）, Ci, stem diameter, primary shoot number, dry matter yield, crude ash （CA） content and in vitro dry matter digestibility （IVDMD）, but significantly decreased Ls （P〈 0. 05） ; Under severe water stress, 0.5 mmol L-1 salicylic acid significantly increased P., water use efficiency （WUE）, plant height, dry matter yield and IVDMD, significantly decreased NDF （P〈0.05）. These results suggested that salicylic acid with the appropriate concentrations improved photosynthesis of Melilotoides ruthenica at the early flowering stage under water stress, and increased the dry matter yield and quality of forage.
出处
《草地学报》
CAS
CSCD
北大核心
2013年第1期127-134,共8页
Acta Agrestia Sinica
基金
"十二五"农村领域国家科技计划项目(2011BAD17B03)资助
关键词
扁蓿豆
水杨酸
水分胁迫
光合作用
饲草品质
Melilotoides ruthenica
Salicylic acid
Water stress
Photosynthesis
Forage quality
