１９９０和１９９１年在木薯（Manihot esculenta Crantz）生长期以植物生长调节物质ＩＰ－１号０，２０，３０和４０ｐｐｍ进行叶面喷洒，结果表明：３０ｐｐｍ处理可使木薯块根产量平均增加５４.４４％，块根淀粉含量平均提高２０.８１％。单株最大薯重提高３１.５５％，块根数增加２１.１７％，块根长度增长１７.６２％，地上部鲜重增加３４.３６％，植株高度增加４.３６％，植株收获期保留青叶数增加１９.４２％，主茎直径增加６.２６％，块根直径增加２.５８％，叶片的叶绿素和蛋白质含量分别提高５.５７％和２５.９６％，叶片光合作用强度提高１５.８６％，而对主茎高度、主茎节数没有明显影响。

It was discussed by detail investigation the IP- 1, a plant growth regulator, could increase the yield of cassava root tubers by 5 4. 4 4 % and the content of starch in root tubers by 20. 18%. It was also found that IP- 1 in 30 ppm could increase the weight of the biggest root tubers of individual plant by 3 1. 15 % , the number of root tubers by 21. 17 % , the length of root tubers by 17. 62%. the fresh weight of above-ground parts by 34. 36%, the height of plants by 3.36 % , the number of green leaves left at the harvest stage by 19. 42 % , the diameter of main stems by 6. 26 % , the diameter of root tubers by 2. 58 % , the contents of chlorophyll and protein in the leaves by 5. 57% and 25. 96% respectively, and increasing the photosynthetic intensity of leaves by 15. 86%. However, IP- 1 had no significant effect on the height and the number of nodes of main stems. The mechanism of increasing the yield of root tubers and the content of starch was also discussed in this paper.