目前普遍认为柑桔用赤霉素保花保果的效果最为稳定,虽有因使用不当会使果皮增厚、成熟期推迟、风味下降等缺点,但很少有发生药害的现象。 1989年6月14～15日,永康县有4个柑桔承包户于上午11时之前、下午16时以后,对柑桔树喷布赤霉素40ppm加0.3％尿素和0.2％磷酸二氢钾液。喷药后第3天就发现有少量落叶,第4天则大量落叶,直到第8天仍有少量落叶。脱落叶片均为老叶,脱落率为40％左右,严重者除当年春梢外,全部叶片几乎落光。调查中还发现,该落叶现象只发生于中熟温州蜜柑,朱红、椪柑及早熟温州蜜柑均无此现象。此外,落叶程度与喷药多少关系很大,叶面喷湿即止的未发现有落叶,喷到滴水为止的则落叶 It is generally accepted that the effect of gibberellic acid on flower protection is the most stable. Although improper use may cause thickening of peel, postponement of maturity, and decrease of flavor, there is very little phytotoxicity. 1989 June 14 ~ 15, Yongkang County, four citrus contractors in the morning before 11 am, after 16 pm, the orange tree spray gibberellin 40ppm plus 0.3% urea and 0.2% potassium dihydrogen phosphate liquid. A small amount of deciduous leaves were found on the third day after spraying and a large number of deciduous leaves on the fourth day. There were still a few deciduous leaves on the eighth day. Lost leaves are old leaves, shedding rate of about 40%, except in those years when the spring shoots, all leaves almost falling light. The survey also found that the deciduous phenomenon occurred only in medium maturing Mandarin, Vermilion, Citrus and Premature Satsuma are no such phenomenon. In addition, the degree of decay and spraying a lot depends on the number of foliage spray wet end is not found in the leaves, spray until the drip is deciduous