大叶桃花心木营养贮藏蛋白质的细胞学研究

Cytological Study on the Vegetative Storage Protein in Swietenia macrophylla King

采用光学显微镜技术研究大叶桃花心木（Ｓｗｉｅｔｅｎｉａ ｍａｃｒｏｐｈｙｌｌａ ｋｉｎｇ）的营养贮藏蛋白质。颗粒状的贮藏蛋白质积累在普通薄壁细胞的中央大液泡中。这些细胞的周缘细胞质中通常含有淀粉粒。在接近落叶期和无叶期，贮藏蛋白质在植株中大量积累，主要分布在次生韧皮部的射线薄壁组织细胞和韧皮薄壁细胞中，且末端小枝的贮藏蛋白质比树干和大根的多。末端小枝贮藏蛋白质的消失与新消生长过程是同步的，表明这些蛋白质被新消生长所消耗。落叶前对一年生枝条基部环剥，萌发的新消生长被抑制，环剥伤口下方贮藏蛋白质的消失受到阻碍。在新梢形成之后，树干和根中贮藏蛋白质明显减少，这些蛋白质的完全消失发生在相应器官形成层活动最活跃的时期。贮藏蛋白质在新梢萌芽后２个月就开始积累，正值高温和长日照时期。

Light microscopic observation of the vegetative storage protein in Swieteniamacrophylla King was made. Granular storage protein was accumulated in the central vacuole, and starch grains generally in the cytoplasm of ordinary parenchyma cells. The storageprotein was accumulated in large quantity in the vegetative organs of Swictenia macrophyllaat the stages of near leaf fall and leaf-absence, and much more in the terminal branchletsthan in the trunk and roots. The protein was stored up mainly in the parenchyma cells ofthe secondary phloem and the phloem ray cells. The disappearance of the storage protein inthe terminal branchlets of Swietenia macrophylla was synchronized with new shoot growth af-ter leaf-absent period, suggesting that the protein was consumed by the new shoots. Whenthe storage protein below the girdled site was blocked, the new shoot growth was also restrained. The storage protein in the trunk and roots diminished dramatically after the newshoot had fully developed and the protein disappeared completely when the cambia of theseorgans were activated vigorously. In the annual growth cycle of Swietenia macrophylla, thestorage protein was accumulated first in the new shoot rather than in the other organs. Theprotein accumulation began two months after bud sprouting when the temperature was highand daylight long.