" So basically you don't have any chloroplasts in tobacco pollen, so there should be no danger for outcrossing" —that is, no foreseeable risk of having the foreign DNA find its way into other plants in nature.
“所以基本上你在烟草花粉中没有任何叶绿体，所以应该没有异型杂交的危险” ——也就是说，没有可预见的风险让外来 DNA 进入自然界的其他植物。