干旱胁迫对不同耐旱型观赏草幼苗生长及碳氮代谢的影响

Effect of Drought Stress on Growth and Carbon-Nitrogen Metabolism of Different Drought Tolerant Ornamental Grass Seedlings

为探究干旱胁迫对不同耐旱型观赏草幼苗生长及碳氮代谢的影响,选择相对耐旱型观赏草蓝滨麦、中间型金边大米草和相对干旱敏感型常绿芒为材料,对其苗期施以4个不同水分处理的干旱胁迫,比较分析其应对干旱胁迫的幼苗生长、碳氮代谢关键产物以及相关酶活性的差异。结果表明:干旱胁迫抑制了3种观赏草株高和地径的生长,且对敏感型观赏草抑制程度较大,最大抑制率分别可达51.7%和34.3%。在碳代谢方面,耐旱型观赏草表现出较高的可溶性糖含量和SS、SPS活性,中度干旱条件下,较CK增长率分别比敏感型观赏草提高了9.8%、12.5%、31.7%。在氮代谢方面,耐旱型观赏草有着较高的FAA和可溶性蛋白含量,含量最高时相比CK提高54.2%、23.7%,比敏感型观赏草含量最高时高出20.1%、11.7%;3种观赏草的GS活性均呈上升趋势,但敏感型变化幅度较缓,且GOGAT、NR活性较低。此外,耐旱型观赏草通过更加稳定的碳氮代谢提高了自身应对干旱胁迫的能力,且不同耐旱型观赏草的幼苗生长应对干旱胁迫时的碳氮代谢主要相关响应物质存在差异。

In order to explore the effects of drought stress on seedling growth and carbon and nitrogen metabolism of different drought-tolerant ornamental grasses,relatively drought-tolerant,intermediate and relatively drought-sensitive ornamental grasses were selected which are Elymus magellanicus,Spartina anglica’Aureomarginata’and Miscanthus transmorrisonensis.Four different water treatments used to compare and analyze the differences in seedling growth,carbon and nitrogen metabolism key products and related enzyme activities in response to drought stress.The results showed that drought stress inhibited the growth of plant height and diameter of three kinds of ornamental grass,and inhibited the drought-sensitive ornamental grass to a greater extent,with the maximum inhibition rates of 51.7%and 34.3%respectively.In terms of carbon metabolism,drought-tolerant ornamental grass showed higher soluble sugar content and SS,SPS activity.Under moderate drought conditions,the growth rate of drought-tolerant ornamental grass was increased by 9.8,12.5,31.7 percentage points compared with sensitive ornamental grass,relative to control group.In terms of nitrogen metabolism,drought-tolerant ornamental grass had higher content of free amino acids and soluble proteins,the highest content was 54.2%,23.7%higher than control,and 20.1,11.7 percentage points higher than drought-sensitive ornamental grass when the content of was highest.In addition,GS activity showed an increasing trend in all three ornamental grasses,but the drought-sensitive ornamental grass showed a slower change,and the activity of GOGAT and NR was lower than drought-tolerant ornamental grass.Drought-tolerant ornamental grass enhances its ability to cope with drought stress through more stable carbon and nitrogen metabolism,and there were differences in the main response substances of carbon and nitrogen metabolism in the seedling growth of different drought-tolerant ornamental grasses to drought stress.