摘要
The distribution of acid phosphatase activity in nucellar cells of wheat ( Triticum aestivum L.) during degeneration has been studied using the lead precipitation method at the electron microscopic level. Acid phosphatase was localized in the slightly condensed nuclear chromatin in nucellar cells without any sign of ultrastructural degeneration. As the nucellar cells started degenerating, the enzyme activity in the cell was observed, in the order from small vacuoles to cell walls, mitochondria, plastids and endoplasmic reticulum. Enzyme activity was the highest in most components of the nucellar cells adjacent to the embryo sac where the degeneration of nucellar cells was the strongest, but it was not observed in the nuclei of the degenerated nucellar cells. The results indicated that the degeneration of nucellar cells was a progressive and orderly process and supported that the degeneration of nucellar cells was a programmed cell death.
采用磷酸铅盐沉淀技术对小麦（ Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．） 珠心细胞衰退过程进行了酸性磷酸酶的超微细胞化学定位研究。结果显示，在未有明显衰退迹象的一些珠心细胞中，酸性磷酸酶只出现在细胞核轻微凝聚的染色质上。随珠心细胞衰退程度的逐渐增大，其衰退特征越来越明显，酸性磷酸酶依次在细胞质中较小液泡、细胞壁、线粒体、质体以及内质网等结构上出现活性反应。紧连胚囊的珠心细胞衰退程度最大，细胞严重变形，酸性磷酸酶定位于细胞绝大部分结构中，但此时变形的细胞核则无酸性磷酸酶活性反应。研究结果表明，小麦珠心细胞的衰退过程中，酸性磷酸酶存在一个有规律的变化。
