Relationship Between Allelopathic Effects and Functional Traits of Different Allelopathic Potential Rice Accessions at Different Growth Stages

In this study,effects of temperature,light and their interactions on allelopathic effects and the functional traits specific leaf area(SLA)and stem mass fraction(SMF)of different allelopathic potential rice accessions at different growth stages were analyzed.The main results were as follows:Allelopathic responses to temperature and light varied with different allelopathic potential rice accessions at different growth stages.With the rise of temperature and the extension of photoperiod,allelopathic effect increased firstly and then decreased at 2–3 leaf stage,but increased constantly at the 4–5 and 7–8 leaf stages in strong allelopathic rice accessions[O.longistaminata,F1(O.longistaminata×RD23),F2(RL159 and RL169)].Temperature had significant impact on allelopathic effect without considering light factors,but light showed little effect on rice allelopathy at the same temperature conditions.The greatest allelopathic effect was attained with moderate temperature and long photoperiod at 2–3 leaf stage in strong allelopathic rice accessions,but all the rice accessions showed weak allelopathic effects at the low temperature condition(15oC/10oC),and the influence of different factors on allelopathy followed a general trend as temperature>leaf stage>light,indicating that among the multiple factors impacting rice allelopathy,temperature was the main factor.Allelopathic characteristics of F1 and F2 to various temperature and light were similar to O.longistaminata,showing that allelopathic genes from wild rice can be expressed in its descendants.Temperature and light also had significant effects on SLA and SMF,and rice allelopathy was closely correlative to SLA in strong allelopathic rice accessions at the 4–5 and 7–8 leaf stages,but there was no correlation between rice allelopathy and SMF at different growth stages.These results suggested that rice adjust the relationship between allelopathy and SLA and adapt to the varied environments,and that high temperature and long photoperiod can enhance rice allelopathic activity.

Development of Straw Decomposition Accelerator and Field Experiment

The mixture ratio of the three strains in the decomposition accelerator was 2∶ 1∶ 2. The experiment on the degradation of straw was carried out in field by using the self-made straw decomposition accelerator. The results showed that the straw decomposition accelerator has an obvious effect of promoting the degradation.The degradation rate was 8. 03% at 10 d and 26. 98% at 20 d,and reached 40. 2% at 30 d.

Control Effect of Sex Pherom one Lure against the Asian Corn Borer( Ostrinia furnacalis) in Field

We studied the trapping effects on Ostrinia furnacalis from the aspects of different hanging heights and different color traps. The results suggested that the hanging height of 1. 5- 2. 0 m received a better trapping effect,but trap color had little impact on trapping effect. The sex pheromone traps at different densities were placed in corn field. The results showed that sex pheromone lure could trap adult O. furnacalis,and it was feasible to apply sex pheromone in short term forecast. Meanwhile,it reduced the number of larvae and eggs,thereby reducing the damage of O. furnacalis. The lure number of 10 per hm2 was more appropriate,which could result in increasing yield of 8. 61% compared with control.