Salt accumulation in vivipavous mangrove plants of Rhizophoraceae

刺根霉的胚。表现出红树植物特有的胎生萌发，胚乳继续生长并从微孔中突出。我们最初使用术语“假种皮”来表示胚乳，但这一个体遗传学研究澄清了突出的结构应该被称为胚乳。突出的胚乳继续在心皮壁发育，最后从心皮壁突出。胚乳的上部位于胚的下胚轴和心皮壁之间。在种子发育的早期阶段，胚靠胚乳细胞退化提供的营养物质生长。而在后期，则依靠种皮细胞退化产生的营养物质生长。在种子发育早期，胚乳细胞吸收由种皮和内果皮细胞退化产生的营养物质生长。胚乳细胞、种皮细胞和心皮壁细胞的产生始于液泡中细胞质的消失。在这种消失之后，细胞器在细胞质中变得扭曲，最终分散成小颗粒在细胞质中。与退化细胞相邻的活细胞的质膜表现为相当活跃和高度波动。退化物质对营养物质的吸收似乎是通过内吞作用。胚乳含盐量逐渐增加，或在胚小且完全被胚乳包围时含盐量较低，而当下胚轴从心皮壁伸出并位于心皮壁与下胚轴之间时含盐量较高。上述结果支持了从心皮壁伸出的胚乳具有保护果实内胚部分免受真菌和细菌入侵的作用。高浓度盐的积累起到天然抗生素的作用。

The embryo of Rhizophora mucronata Lam. Shows viviparous germination which is characteristic for the mangrove plants, and the endosperm continues to grow and protrudes from the micropyle. We first used the term, aril for endosperm, but this ontogentetical study clarified that the protruded structure should be termed as endosperm. This protruded endosperm continues to develop in the carpel wall and finally protrudes from the carpel wall. The top portion of endosperm takes position between the hypocotyl of the embryo and carpel wall. In the early stage of seed development, the embryo grows by the nutrients supplied by the degeneration of endosperm cells. In the later stage, however, it grows by the nutrients resulted from the degeneration of seed coat cells. In the early stage of seed development, the endosperm cells grow absorbing nutrients produced by the degeneration of seed coat and endocarp cells. The generation of endosperm cells, seed coat cells and carpel wall cells begins by the disappearance of tonoplast in the vacuole. After this disappearance organelles in the cytoplasm become distorted and finally disperse as small particles in the cytoplasm. The plasma membrane in cells alive next to degenerating cells appears as quite active and highly undulated. The absorption of the nutrients by the degenerated materials seems to be by endocytosis. The salt contents in the endosperm increases gradually, or it is low when embryo is small and entirely surrounded by endosperm while it is high when the hypocotyle protrudes from the carpel wall and takes position between the carpel wall and hypocotyl. The above mentioned results support the working hypothesis that the endosperm protruded from the carpel wall has a function to protect the embryo portion inside the fruit from the attack by fungi and bacteria which might find the way into the fruit. The accumulation of high concentration salt acts as natural antibiotic.