四、杂种不育(hybrid sterility) 1.表现形式 ●花粉不育pollen sterility ●胚囊不育ES sterility:卵细胞或极 核不正常 ●胚胎或胚乳发育异常abnormality in embryogensis and the development of endosperm Biology of plant reproductionBiology of plant reproduction 26 四、 杂种不育（hybrid sterility） 1. 表现形式 ●花粉不育pollen sterility ●胚囊不育ES sterility：卵细胞或极 核不正常 ●胚胎或胚乳发育异常abnormality in embryogensis and the development of endosperm