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为给干旱区苜蓿产业的科学发展提供理论依据,以‘陇东’、‘大叶’和‘阿尔冈金’苜蓿作为材料,采用盆栽控水试验,研究了不同土壤干旱胁迫条件下3个苜蓿品种的总生物量、根冠比、干物质积累率、净光合速率、蒸腾速率、水分利用效率、气孔导度以及叶绿素a、叶绿素b和类胡萝卜素含量等指标的变化。结果表明:随着土壤相对含水量的减少,3个苜蓿品种的净光合速率逐渐下降,其中‘阿尔冈金’苜蓿始终保持比其他2个苜蓿品种较高的净光合速率,表现出较好的潜在光合能力;3个品种植株总生物量有不同的减少趋势,其中‘大叶’苜蓿在土壤相对含水量为50%~55%条件下总生物量的减少幅度较小,仍保持较高的生物量;根冠比和干物质积累率逐渐上升,‘陇东’苜蓿和‘阿尔冈金’苜蓿的增大幅度极显著;‘大叶’苜蓿的叶绿素a、叶绿素b、类胡萝卜素含量和Chla/Chlb比值随着干旱胁迫的加大而增高。就生物量而言,‘大叶’苜蓿的生物产量最多;就抗旱性而言,‘阿尔冈金’苜蓿的抗旱性最强。
In order to provide a theoretical basis for the scientific development of the alfalfa industry in arid areas, pot experiments were conducted to study the effects of three alfalfa treatments under different soil drought stress conditions on Medicago sativa ’Longdong’, ’Da Ye’ and ’Algonquin’ Total biomass, root / shoot ratio, dry matter accumulation rate, net photosynthetic rate, transpiration rate, water use efficiency, stomatal conductance and chlorophyll a, chlorophyll b and carotenoid content. The results showed that the net photosynthetic rate of three alfalfa cultivars decreased gradually with the decrease of soil relative water content. The ’Algonquin’ alfalfa maintained higher net photosynthetic rate than the other two alfalfa cultivars, Potential photosynthetic capacity. The total biomass of the three cultivars tended to decrease in different ways. The reduction of total biomass of the ’big-leaf’ alfalfa under the relative soil water content of 50% -55% was relatively small and remained high Biomass, root / shoot ratio and dry matter accumulation rate increased significantly, the increase of ’Longdong’ alfalfa and ’Algonquin’ alfalfa was extremely significant; the contents of chlorophyll a, chlorophyll b and carotenoid Chla / Chlb ratio increased with drought stress. In terms of biomass, ’big-leaf’ alfalfa produced the most biomass; in terms of drought resistance, ’Algonquin’ alfalfa had the strongest drought resistance.