摘要
实地 (杭州 )调查了桑稻混种地区水稻花粉飘落到桑叶上的浓度 ,同时对转 Bt基因水稻花粉向桑叶上飘飞程度进行了田间试验。 2 0个采样点的调查结果显示 ,超过一半 ( 5 4 .5 % )的桑叶检测到了水稻花粉 ,其浓度变化范围为 1 3.3～ 1 99.0粒 /cm2 ,平均浓度为 92 .9粒 /cm2 ,与 1 0 9.1粒 /cm2 (该浓度影响家蚕生长发育 )持平 ( t=0 .1 0 ,P>0 .5 )。不同桑稻距离 ( 0～ 1 0 m)的桑叶花粉浓度总体上是距离越近花粉浓度越高。将处于开花期的转基因 Bt水稻和非转基因水稻植株 (各 3株 )同时放入桑园中 ,然后观察水稻植株周边桑叶飘落上水稻花粉的浓度。两次试验采集的桑叶自然飘落的水稻花粉平均为 3.8粒 /cm2 ,这一结果证明水稻花粉可飘落到桑叶上 ,从而支持上述调查结果 ;试验同时证实转基因 Bt水稻和非转基因水稻植株的花粉飘飞能力没有差异。以上研究结果表明 ,Bt水稻在我国南方养蚕地区推广将可能对家蚕的生长发育造成负面影响。
Sericulture is an important industry for silk production in Southern China. Typi cally, mulberry （Morus L.） plants are grown on the ridge of or beside rice fiel ds in this area, the so-called mulberry-rice mixed cropping area. The allowing o f limited environmental release, and presumable commercial release later, of Bt (Bacillus thuingiensis) transgenic rice (Oryza sativa L.) by China raise d a doub t that if Bt transgenic rice pollen, which will be wind-dispersed on mulberry l e aves, is harmful for sericulture in the mulberry-rice mixed cropping area. The s tudies reported here contribute to the exposure characterization necessary for a ssessing the risk of Bt rice pollen to silkworm（Bombyx mori L.）larvae. In part icular, this paper describes the naturally occurring densities of rice pollen on mulberry leaves during rice anthesis for a number of geographic locations and u nder a variety of environmental conditions at mulberry-rice mixed cropping area in China. The density of rice pollen on leaves of mulberry plants outside of ricefields wa s measured at different locations （total 20 sampling sites）in Hangzhou, China on September 16 and 18, 2001. Three scopes were observed immediately under micro scope for every leaf after it was picked. Before observation, 1%I-KI solvent wa s spread on leaves. Upon contact with the solvent, pollen turns dark blue and is easily observed. Pollen was found on 54.5% of total 255 sampling leaves. The a ve rage density of all leaves was 92.9 grains per cm2 (13.3~199.0 grains per c m2), which is not significantly different from 109.1 grains per cm2, a harmful de nsi ty for silkworm larvae (t=0.10, P>0.5). A pollen density of 221.5 gra ins per cm2 (over twice the toxic level of 109.1) was observed on 16.2% of leaves. In ge ne ral, pollen density was progressively lower from the field edge outward. In one case within this study, the average pollen density of leaves from mulberry plant s that are 10m away from the ricefield also reached the dangerous level of
出处
《生态学报》
CAS
CSCD
北大核心
2003年第4期826-833,共8页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目 ( 30 1 70 1 81 )~~
