Prevention of barnacles on planted Rhizophora stylosa Griff seedlings with pesticide malathion and related eco-physiological effects
- 生命科学－已发表论文 
设置4种施药频度(3、7、14和28d)和马拉硫磷4种浓度(分别为原农药浓度45%的1/200、1/400、1/600和1/800)处理,在初植红海榄(Rhizophora stylosa Griff)幼苗上开展了1年防治藤壶试验。结果表明:随施药浓度和频度提高,处理组幼苗上藤壶生物量显著降低,且所有处理组均显著低于对照组(P<0.001);红海榄茎生物量和高度对施药浓度和频度不表现规律性反应;同一浓度的28d频度处理组幼苗的叶和根生物量及叶面积均低于其他频度处理组;在同一浓度下,施药频度越高叶数保持越多;3、7和14d频度处理组幼苗死亡率均较低,仅0~5%,28d频度处理组死亡率较高,为11%~22%,但对照组死亡率达39%;幼苗死亡率与藤壶生物量之间存在显著正相关关系(P<0.001),与叶生物量、叶数、根生物量及新生器官生物量存在显著负相关关系(P<0.001),与茎高、茎生物量、原繁殖体生物量等相关性不显著;施用农药造成红海榄幼苗叶绿素总量降低,Chl(a/b)比值上升,同时抗氧化酶系SOD和POD活性增大。建议在平均海平面高程的滩涂上造林,可采用频度14d、浓度1/800马拉硫磷喷雾防治藤壶。A one-year experiment on the prevention of the barnacles on planted Rhizophora stylosa Griff seedlings with malathion was conducted at Yingluo bay of Guangxi, China. Four pesticide concentrations (1/200, 1/400, 1/600, and 1/800 seawater solution of the original malathion concentration (45%)) and four spraying frequencies (every 3, 7, 14, and 28 days) were installed. The results showed that with increasing pesticide concentration and spraying frequency, the barnacle biomass on the seedlings decreased significantly, and all the treatments had a significantly lower barnacle biomass than the control (P<0.001). The seedlings stem biomass and height did not have definite patterns of responses to the pesticide concentration and spraying frequency. At the same pesticide concentration, spraying it every 28 days gave the lowest root biomass, leaf biomass and leaf area, and the more the spraying frequency, the more the leaves preserved. Also at the same pesticide concentration, spraying it every 28 days gave the highest mortality (11%-22%) of the seedlings, while spraying every 3, 7 and 14 days only gave 0-5% of the mortality. However, the mortality in control group reached 39%. Statistical analysis indicated that the seedlings mortality had a significant positive correlation with barnacle biomass (P<0.001), significant negative correlations with leaf biomass, leaf number, root biomass, and neonatal biomass (P<0.001), but no significant correlations with seedlings stem height, stem biomass, and remained propagule biomass. Spraying malathion decreased the seedlings leaf chlorophyll content, but increased the leaf Chl (a/b) ratios and SOD and POD activities. It was proposed that in case of mangrove forestation on tidal flats at mean sea level, spraying malathion at the concentration of 1/800 and with a frequency of every 14 days could prevent barnacle effectively.