| Eleocharis plantagineiformis is a corm breeding perennial weed with strong regeneration ability. Its occurrence can hardly be controlled by soil-treatment of herbicides, which does great harm to rice growth. In this paper, the condition of breaking dormancy of the E. plantagineiformis corms and the effect of planting density, planting depth and water depth on its rate of germination, growth and production were studied. Moreover, the suppressions, exerted by nine kinds of herbicides foliage-treatment, on corm formation of E. plantagineiformis were assessed. In addition, the mechanisms leading to different controls between bensulfuron-methyl and pyrazosulfuron-ethyl were studied. The results are as follows:The test of breaking dormancy of E. plantagineiformis corms showed that the low-temperature treatment can break the corms dormancy effectively, and the longer the cold treatment, the faster the growth rate and the higher the germination rate. Light period had no significant effect on germination. Studies on E. plantagineiformis emergence influenced by combined factors showed that corm germination rate was faster when it was treated by2corm/barrel,2cm soil depth,0cm water depth,4corrm/barrel,2cm soil depth and0cm water depth within a35-day testing period; while the corm germination rate was the lowest when it was treated by4corm/barrel,8cm soil depth and10cm water depth; After planted for40-90days, the amount of E. plantagineiformis ramets and stems of4corm/barrel was significantly more than the2corm/barrel, the2cm depth more than8cm depth,0cm and5cm layer of water treatment significantly more than10cm water layer; Between60and90days, E plantagineiformis plants processed in8cm-depth soil were significantly higher than those of2cm-depth soil; E. plantagineiformis plants processed in5cm or10cm water layer were significantly higher than those in no water layer processing; E. plantagineiformis stems of4conn/barrel processed outweighed those of2corm/barrel while the0cm and5cm water layer processed surpassed the10cm water layer processing. There were significant differences among the amounts of corm breeding for disparate plant depths:the amount of2cm soil depth processing was significantly more than8cm soil depth processing; the total weight of4 corm/barrel processing was significantly more than that of2corm/barrel processing; The average reproductive rate of single corm of2corm/barrel processing was significantly higher than4corm/barrel processing, and2cm soil depth processing was obviously more than8cm soil depth processing.The results of the suppressions exerted on the corm formation of E. plantagineiformis by nine kinds of herbicides foliage-treatment showed that the number of E. plantagineiformis corm was completely generated by pyrazosulfuron·carfentrazone-ethyl (30%WP) with a dose of54g a. i.·hm-2and of67.5g a. i.·hm-2. When the dose of pyrazosulfuron-ethyl (10%WP) was45,52.5g a.i.·hm-2, the inhibitory percentage nearly amounted to100%. Being treated by MCPA-sodium (56%SP) with a dose of756,924g a. i.·hm-2, the inhibitory percentage was95.04%,99.43%in number and95.68%,99.62%in yield, respectively. There was lower suppression in corm number and efficient inhibition in yield and size after treatment by bensulfuron-methyl· carfentrazone-ethyl (10%WP) with a dose of57,68.4g a. i.·hm-2. However, it had tiny effects on the number, yield and size of E. plantagineiformis corm which had been treated by other tested herbicides involving fluroxypyr, bentazone and carfentrazone-ethyl.The results of bensulfuron-methyl, pyrazosulfuron-ethyl, bensulfuron-methyl mixed with carfentrazone-ethyl and pyrazosulfuron-ethyl mixed with carfentrazone-ethyl foliage-treatment against E. plantagineiformis showed that all of15g a.i.·hm-2,30g a.i.·hm-2,60g a.i.·hm-2pyrazosulfuron-ethyl and15+3.75g a.i.·hm-230+7.5g a.i.·hm-2,60+15g a.i.·hm-2pyrazosulfuron mixed with carfentrazone-ethyl would have huge influence on the quantity and weight of the breeding corms,among which30+7.5g a.i.·hm-2,60+15g a.i.·hm-2pyrazosulfuron mixed with carfentrazone-ethyl exhibited the best inhibitory effect, as there were no E. plantagineiformis stalks after the processing of foliage-treatment tests; the weight of corm and single ball generated by bensulfuron-methyl mixed with carfentrazone-ethyl60+15g a.i.·hm-2processing decreased obviously, while no significant changes in the number of corms breeding. Other bensulfuron-methyl treatment on E plantagineiformis corm formation also had no obvious effects were observed.The results of the inhibitory effect of bensulfuron-methyl and pyrazosulfuron-ethyl to E. plantagineiformis in vitro ALS activity under various conditions showed that the inhibitory rates of0.1mg·L-1、0.5mg·L-1、1mg·L-1、5mg·L-1bensulfuron-methyl to E. plantagineiformis stems in vitro ALS activity were weaker than the same concentration of pyrazosulfuron-ethyl. The inhibition rate of10mg/L bensulfuron-methyl and10mg·L-1pyrazosulfuron-ethyl was89.91%and89.32%, respectively.After stems being treated for1-15days with10%bensulfuron-methyl and10%pyrazosulfuron-ethyl, respectively, malondialdehyde content in E. plantagineiformis stalk treated by bensulfuron-methyl was less than that by pyrazosulfuron-ethyl. After spraying for10and15days, soluble sugar content in the stems processed by bensulfuron-methyl was less than that of pyrazosulfuron-ethyl processing. However, there was no significant difference after20days. The sucrose content within stalks decreased, and both of them were significantly lower than the control after spraying for10and20days. Sucrose content in the stems processed by bensulfuron-methyl was significantly less than that by pyrazosulfuron-ethyl processing after spraying for10days. Sucrose content in stalks treated by52.5g a.i.·hm-2pyrazosulfuron-ethyl was much more than other treatments after spraying for15days. There was no obvious difference between the sucrose contents of the two chemical treatments after spraying for20days. |
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