Effects of seed soaking in paclobutrazol on the growth of Jatropha curcas seedlings under salt stress and its physiological mechanism | 多效唑浸种对盐胁迫下麻疯树幼苗生长的效应及其生理机制

Chinese. 研究600 mg.L-1多效唑（PP333）浸种对200 mmol.L-1NaCl胁迫处理下麻疯树幼苗相对生长速率（RGR）、干物质积累速率（DMAR）、含水量（WC）、根冠比（R/S）以及叶片电解质渗漏率（EL）、渗透调节能力（OAA）、抗氧化能力、离子分配等的效应。结果表明：与对照相比,PP333浸种处理显著降低植株RGR、叶片SOD和POD活性,显著提高植株DMAR、WC和R/S,显著提高叶片OAA、K＋含量和K＋/Na＋比率;200 mmol.L-1NaCl胁迫下麻疯树幼苗RGR、DMAR、WC、R/S、SOD活性、CAT活性、K＋含量和K＋/Na＋比率均显著下降,而EL、MDA含量、POD活性、Na＋和Cl-含量均显著上升;600 mg.L-1PP333浸种处理能显著提高NaCl胁迫下植株的RGR、DMAR、WC和R/S,同时显著降低叶片EL、Na＋和Cl-含量,显著提高叶片OAA、SOD和CAT活性,显著提高K＋含量和K＋/Na＋比率,显著降低MDA含量和POD活性。结论：PP333浸种能显著促进麻疯树幼苗的生物量积累,抑制地上部伸长,即矮壮效应,从而大大改善其对盐渍的适应能力,其耐盐性的提高是因为PP333浸种改善了植株的抗氧化能力、渗透调节和离子平衡。

English. This study evaluated the effects of seed soaking in 600 mg. L-1 paclobutrazol （ PP333 ） on the growth of Jatropha curcas seedlings under salt stress, and the relative growth rate （ RGR）, dry matter accumulation rate （DMAR） , water content （ WC ）, root/ shoot ratio （R/S） , leaf electrolyte leakage （EL） , osmotic adjustment ability（OAA） , antioxidation and ion distribution in leaf were de- termined. The results obtained were as follows： compared with the control, the treatment of seed soaking in 600 mg. L-1 PP333 significantly decreased RGR, and activities of SOD and POD, and increased DMAR, WC, R/S, and increased OAA, K＋, K＋/Na＋ ratio in leaves. The treatment of 200 mmol.L-1 NaC1 significantly decreased the seedling RGR, DMAR, WC, R/S, SOD activity, CAT activity, K＋ content and K＋/Na＋ ratio, and increased EL, MDA content, POD activity, contents of Na＋ and Cl-. However, compared with only NaCl treatment, the plant RGR, DMAR, WC, R/S, and the leaf OAA, SOD activity, CAT activity, K＋ content and K＋/Na＋ ratio also increased, but leaf EL, contents of Na＋, Cl- and MDA, and POD activity obviously decreased with PP333 application under NaCl stress. To sum up, seed soaking in 600 mg.L-1 PP333 stimulated J. curcas seedlings＇ growth obviously, making the plant dwarf and strong, and their salt adaptation was improved remarkably. The above-mentioned stimulation and improvement were due to the improvement of leaf antioxidation, osmotic adjustment and ion homeostasis caused by PP333.