菜心生长发育及产品器官形成的研究──菜苔生长发育的内部结构

STUDY ON THE GROWTH,DEVELOPMENT AND FORMATION OF PRODUCT ORGAN IN Brassica parachinensis──THE STRUCTURE IN THE GROWTH AND DEVELOPMENT OF FLOWERING STEM

本文对菜心（ＢｒａｓｓｉｃａｐａｒａｃｈｉｎｅｎｓｉｓＢａｉｌｅｙ）的菜苔形成过程内部结构特点，进行解剖学研究，为菜心优质丰产提供解剖结构依据。结果表明：从菜苔形成至采收期间，近茎端上段始终具分裂能力，皮层与髓部薄壁组织发达，细胞小，延长少，排列紧密，细胞间隙小而少，维管束小，未木化，为优质菜苔的标志；茎苔中段薄壁细胞不那么紧密，细胞间隙增多增大，形成层保持着分裂活动。菜苔有明显的节间伸长和增粗，维管束木质部大于韧皮部，品质不及上段；茎苔基部皮层与髓部薄壁组织明显疏松，细胞间隙多而大、维管束多而密，次生木质部比例大，导管大，多且木化，品质变劣，无食用价值。

The purpose of this study was to identify the characteristics of the internal struc-ture during flowering stalk formation assooiated with high quality and yiedl of Brassioaparachinensis Bailey. From the initiation of stalk formation till harvest , the subapical portionof the stalk maintained dividing capacity.The parenchyma of the cortex and the pith werewell developed.CellS were small and arranged closely with few and small intercellular spaces.The vascular bundles in the subapicsl stalk were small and unlignified.Such characteristicsrevealed the high quality of the flowering stalk.In the middle part of the stalk ,the parenchy-ma cells were not arranged so closely with larger intercellular spaces.Due to the dividing ca-pacity of the cambiumm the internode elongation and the broadening growth of the stalkwould be maintained and the yield increased.As for the basal part of the stalk ,the amount ofvascular bundles in the xylem were more than that in the phloem.The parenchyma cells inthe cortex and pith were arranged scatteredly and the intervals were more and larger withmany vascular bundles.The proportion of secondary xylem increased and the vessels werebigger and lignified ,thus having no edible value because of the low quality.