洋葱卵细胞的分离

Isolation of Egg Cells from Allium cepa L.

将洋葱的胚珠置于酶液中酶解50-110 min后剥去其珠被,可清楚地看到珠心中的胚囊轮廓。用解剖针将珠心从中部横切,然后挤压其珠孔部位,卵器细胞从胚珠的切口处逸出。再用显微操作仪的玻璃针将卵细胞和两个助细胞分开,达到分离洋葱卵细胞的目的。酶对分离卵细胞具有重要作用,在最佳的酶液浓度[0.02%果胶酶Y23、0.08%果胶酶（Serva）、0.05%纤维素酶和0.05%半纤维素酶]下酶解胚珠110 min后,解剖1 h可从24个胚珠中分离出10个卵细胞（41.67%）。随着胚囊的发育,两个助细胞的体积出现明显的二形性。洋葱生活卵细胞的分离为开展洋葱离体受精建立了基础,也为研究洋葱卵器细胞的发育创造了条件。

Viable egg cells ofAllium cepa L. were isolated using enzymic digestion and mechanical dissec-tion. The onion ovules were incubated in an enzymic solution for 50-110 rain and then peeled its two intaguments. The outline of embryo sac in nucellus was seen clearly. Using a dissecting needle cutting necellus transversely and pushing its micropyle part, three cells of egg apparatus could be released from cut end of the nucellus. The egg cell could be separated with two synergids, reaching the purpose of isolation of onion egg cell. Enzymes are very im-portant for isolating egg cell, and in optimal enzyme solution containing 0.02% Pectolyse Y-23, 0.08% Pectinase （Serva）, 0.05% Cellulase （Onozuka RS）, 0.05% Hemicellulase （Sigma）, 10 egg cells （41.67%） could be isolated from 24 ovules in 1 h. With embryo sac development, two synergids display dimorphism in size. The isolation of onion egg cells makes a base for its in vitro fertilization, and provides the condition to study onion egg development using methods of molecular biology.