Qiu Yi Lan, Liu Ru Shi, Ye Lv, Tian Hui
School of Life Sciences, Hunan Normal University, Changsha 410081, China.
Fen Zi Xi Bao Sheng Wu Xue Bao. 2008 Feb;41(1):61-9.
Potassium antimonite precipitation was used to locate calcium in the central cell of lettuce (Lactuca sativa L.) before and after pollination. At 3d before anthesis, two polar nuclei of central cell separately located at two polarity of the cell, and few calcium precipitates (ppts) appeared in the polar nuclei and cytoplasm, but some ppts in its small vacuoles. At 2d before anthesis, two polar nuclei moved toward the middle of the cell and fused to form a secondary nucleus, and the ppts evidently increased in the nucleus and cytoplasm. At 1d before anthesis, secondary nucleus again moved toward micropylar end and located near the egg to prepare for fertilization. Calcium precipitates were mainly accumulated in the secondary nucleus. After pollination and before fertilization, the distribution of calcium ppts was similar to that before pollination. At 4h after pollination, the central cell was fertilized, and calcium ppts evidently increased in the cell and numerous were accumulated in its nucleus and cytoplasm. At 6h after pollination, the primary endosperm nucleus completed its first division and formed two dissociate endosperm nuclei, and still many calcium precipitates appeared in the nucleus and cytoplasm. With endosperm development, calcium ppts decreased in the endosperm cell. At 1d after emasculated and without pollination, the secondary nucleus of the cell still bordered on the egg and some calcium ppts appeared in the secondary nucleus. The results indicated that the temporal and spatial changes of calcium in the central cell may play an important physiological role during the development of the central cell and endosperm.
采用焦锑酸钾沉淀法对授粉前后生菜（Lactuca sativa L.）中央细胞中的钙进行定位。在开花前3天，中央细胞的两个极核分别位于细胞的两极，极核和细胞质中几乎没有钙沉淀，但在其小液泡中有一些沉淀。在开花前2天，两个极核向细胞中部移动并融合形成次生核，核和细胞质中的沉淀明显增加。在开花前1天，次生核再次向珠孔端移动并位于卵细胞附近，为受精做准备。钙沉淀主要积累在次生核中。授粉后受精前，钙沉淀的分布与授粉前相似。授粉后4小时，中央细胞受精，细胞中的钙沉淀明显增加，大量沉淀积累在核和细胞质中。授粉后6小时，初生胚乳核完成第一次分裂，形成两个游离的胚乳核，核和细胞质中仍有许多钙沉淀出现。随着胚乳发育，胚乳细胞中的钙沉淀减少。去雄未授粉1天后，细胞的次生核仍靠近卵细胞，次生核中出现一些钙沉淀。结果表明，中央细胞中钙的时空变化可能在中央细胞和胚乳发育过程中发挥重要的生理作用。
