多效唑对几种果园双子叶杂草种子发芽的抑制作用

在生长箱中25±1℃恒温、光暗周期12／12h的条件下，研究了多效唑对裂叶牵牛Pharbitis nil（L.）Choisy，圆叶牵牛Pharbitis purpurea（L．）Voigt，苦苣幕Sonchu oleraceus L．、小藜 Chenopodium serotinum L，白苋Amaranthus albus L．等5种双子叶果固有害杂草种子萌发的影响。结果表明：在一定浓度范围内。随着多效唑浓度的增加上述5种杂草种子的发芽率和发芽势均显著或极显著降低，胚根、胚芽的伸长也受到了显著抑制。种子发芽及胚根、胚芽伸长对多效唑反应的敏感程度因杂草种类而异：白苋为极敏感型，5mg／L的多效唑处理极显著地降低了胚根胚芽长度。10mg／L的处理极显著地降低了发芽率和发芽势，15mg／L的处理的种子发芽率和发芽势降至50％以下，35mg／L的处理完全抑制了其种子萌发；苦苣莱为敏感型，25mg／L的处理极显著地降低了发芽率，100mg／L的处理的种子发芽率降至50％以下；小藜、圆叶牵牛和裂叶牵牛为不敏感型，200ms／L、150mg／L和200mg／L处理极显著降低发芽率，400mg／L浓度以上处理的小黎种子发芽率降至50％以下，圆叶牵牛种子在200。350mg/L．裂叶牵牛种子在200-500mg／L的多效唑浸渍中仍有90％左右的发芽率。

Effects of Paclobutrazol on Germination of Weed Seeds in Orchard

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.