关键词: 多效唑 杂草种子 发芽率 发芽势 胚根 胚芽

Abstract:

Under the condition of constant temperature at 25 ± 1℃ and 12 hour light/d, the effects of paclobutrazol on germination of 5 dicotyledonous weed seeds in orchard, which are Pharbitis purpurea （ L. ） Voigt, Pharbitis nil （ L. ） Choisy, Chenopodium serotinum L , Amaranthus albus L and Sonchus olerraceus L. , were studied. The results showed that in a certain concentration range, the germination percentage and germination energy markedly or greatly markedly declined with the concentration of paclobutrazol increasing, and the growth of radical and plumule was inhibited markedly at the same time. The sensitivities of these weed seeds varied： The Amaranthus albus L. was the most sensitive, when the concentration of paclobutrazol was 5 mg/L, the grrowth of its radical and plumule was markedly inhibited, and the germination percentage and germination energy of its seeds were decreased markedly when the concentration of paclobutrazol reach 10 mg/L ,and they declined under 50 percent when the concentration of paclobutrazol was 25 mg/L, and the seedswouldnt germinate when the concentration of paclobutrazol arrived at 35 mg/L; The seeds of Sonchus oleraceus L. were sensitive to paclobutrazol, the germination percentage was remarkably inhibited by 25 mg/L paclobutrazol , and the germination percentage declined under 50 percent when these seeds were treated by 100 mg/L paclobutrazol. But the seeds of Chenopodium serotinum L ,Pharbitis purpurea （L.） Voigt and Pharbitis nil （L.） Choisy weren＇t sensitive, the concentrations of paclobutrazol which can remarkedly decrease the seeds germination percentage were 200 rag/L, 150 rag/Land 200 mg/L respectively. Only when the concentration of paclobutrazol was above 400 mg/L, the germination percentage of Chenopodium serotinum L. seeds could be decreased under 50%. And the germination percentages of Pharbitis purpurea （ L. ） Voigt and Pharbitis nil（ L. ） Choisy seeds went up after they slowly decliined to 90 % with the increasing of paclobutrazol concentration.

Key words: paelobutrazol ;weed seeds ;germination percentage, germination energy, radical , plumule