多效唑对高羊茅弱光下生长及其碳氮代谢的调控作用

本研究为揭示多效唑对高羊茅(Festuca arundinacea)生长和碳氮代谢的影响，设置了自然光照(光通量密度为200μmol·m^-2·s^-1)和弱光(光通量密度为40μmol·m^-2·s^-1),喷施200 mg·L^-1多效唑与不喷施的双因素试验，并测定了高羊茅形态、碳氮代谢相关指标。结果表明：高羊茅在弱光下，其株高、叶宽、分蘖数和生物量显著下降(P<0.05),淀粉、还原糖、铵态氮、游离氨基酸含量以及碳氮比均降低。此外，多效唑处理能增强碳氮代谢水平，使弱光下碳氮比、谷氨酰胺合成酶和硝酸还原酶的活性分别提高了13.98%,17.38%和69.09%,最终使株高降低、分蘖增加。综上，多效唑处理能增强高羊茅耐弱光的能力，平衡其碳氮代谢，从而使其维持在一个良好的生长状态。

Regulatory Effect of Paclobutrazol on Growth and Carbon/Nitrogen Metabolism of Tall Fescue under Low Light

In order to reveal the effects of paclobutrazol (PBZ) on the growth and metabolism of carbon and nitrogen in turfgrass tall fescue (Festuca arundinacea),a two-factor experiment was conducted under two light levels of natural light (200 μmol·m^-2·s^-1 PPFD) and low light (40 μmol·m^-2·s^-1 PPFD),and two treatments of 200 mg·L^-1 and 0 mg·L^-1 PBZ,to discover the changes of morphologyical and physiological parameters. The results indicated that under low light,the plant height,leaf width,and tiller numbers were decreased significantly (P< 0.05) in tall fescue,and the contents of starch,reducing sugar,soluble sugar,ammonium nitrate,free amino acid,and C/N ratio were all decreased. Moreover,the PBZ application enhanced the carbon and nitrogen metabolism of tall fescue under low light,and increased C/N ratio,and activities of glutamine synthase and nitrate reductase by 13.98%,17.38% and 69.09% respectively,which finally resulted into the decrease of plant height and the increase of tiller numbers. In conclusion,PBZ can balance carbon and nitrogen metabolism,and promote its growth in terms of an enhancement of low light tolerance,in tall fescue.