油菜抽苔期施多效唑的降高防倒效果及其应用途径

本文研究了油菜抽苔期施用多效唑降低株高、防止倒伏的效果及其与施氮水平和赤霉酸的配合效应,结果表明:油菜抽苔期施用多效唑可显著降低植株高度和分枝高度,增加根颈粗度,提高抗倒伏能力,这种效果随多效唑浓度的增加而提高。多效唑对油菜产量的效应表现为两方面,一是在中低肥水平下植株生长较差,多效唑浓度较高时,因过分抑制生长,使株体变小而减产;二是多效唑处理后因提高了植株抗倒能力,避免或减轻倒伏造成的损失而间接增产,因此多效唑只适于高肥水条件下植株生长过旺,有倒伏威胁的田块。油菜抽苔初期150ppm多效唑处理后26天又喷施40ppm的赤霉酸可刺激生长发育和开花结果,既有一定降高防倒效果,也有一定增产作用。

EFFECT OF PALCOBUTRAZOL APPLIED AT THE BOLTING STAGE OF THE OLLSEEDRAPE ON PLANT HEIGHT AND ITS APPLICATION CONDITIONS

The effect of palcobutrazol (PP_(333)) applied at the bolting stage o the oilseed raPe and its. combinative effect with nitrogen level and gibberellin (GA3) on plant height and lodging resistance were studied. The results showed as follows, pp_(333) applied at the bolting stage of the oilseed rape signifficantly decreased plant height, lowered primary branching height, and thickened root collar, as a result, increased lodging resistance. The higher the concentration of PP_(333), the stronger the effect, The effect of PP_(333) on the rapeseed yield was showed on two sides, PP_(333) decreased the yield by inhibiting growth too much under low nifrogen level, especially under high concentration of PP_(333), but it might increase the yield indirectly by incresing lodging resistance and reducing yield loss of lodging under high nitrogen level. 40ppm GA3 applied 26 days affter applying PP_(333) at the bolting stage promoting growing and flowering. Both effect of increasing lodging resistance and rapeseed yield were showed in this case.