Author: Wang His-ching
J Integr Plant Biol 1956, 5 (4): -.
This paper describes the results of a study of Nelumbo nucifera Gaertn. It is composed of two parts, the external morphology of the vegetative body and the organization of the buds.
Ⅰ. The morphology of vegetative body
From germination to sexual maturity the vegetative body passes through 3 distinct developmental phases: (1) the seedling period, (2) the juvenile shoot period, and (3) the annual shoot period.
The seedling is erect and with short zigzag axis. It possesses floating leaves arranged alternately and its internodes are very short. The radicle is quite undeveloped, and there are many adventitious roots growing on the nodes. The transition from the seedling period to the juvenile period is sudden.. The internodes bearing the bud which develops into the juvenile shoot elongate remarkably, and the succeeding internodes are also long. The erect seedling becomes a horizontal juvenile shoot. Every leaf grows out from the dorsal side of each node on the rhizome. Their leaves except the first two which are floating become emergent. Around the nodes are produced numerous adventitous. roots. When the cold season comes, the last two or three internodes of the juvenile shoot become the swollen parts of the rhizome. This specialized parts serve as an organ of vegetative propagation. The swollen internodes store food material, and bear a terminal bud which expands in the next spring.
The morphological structure of the annual shoot is quite similar to the juvenile shoot, except that its vegetative organs show marked increase in size and length and it bears sexual reproductive organs–flower or flower primordium, Thus the juvenile shoot there bears only vegetative buds, while on the annual' shoot there are mixed buds. The rhizome of the annual shoot is composed of distinct joints or rhizome units. In- one growing season about 17 of these rhizome units may be formed. That makes the main axis and whole ramification of the vegetative body becomes the shoot system The total length of the main axis is about 10 meters.
The length of the internodes and the area of the leaf laminae are very closely correlated, there is also a correlation between the diameter of the internodes and the area of the leaf laminae. Moreover, there exists a close relationship betwee nsexual reproductive organ development and vegetative propagation. Only those last joints where flowers no longer develop become greatly thickened and form organs of vegetative propagation.
Ⅱ. The organization of the bud
The organization of the bud of N. nucifera is complex and peculiar. Complete.
elucidation must await detailed developmental studies. According to the observation and anatomy of buds, a series of problems should be studied before we can find the answer. In this paper it suffices to points out salient features of the bud organization.
1. There is extensive teloscoping of bud within bud. In the hud that is to-develop into the juvenile shoo b three buds of different developmental orders are teloscoped one into another . In the terminal buds of the annual shoot, as many as 5 buds of different developing orders are thus telescoped . In addition, there are included in these buds axillary buds and also flower buds.
2. The scale in N. nucifera is greatly developed, not only the bud possesses the scale, but also the young foliage leaf is enclosed in a scale; not only the vegetative bud and mixed bud are covered with scales but even the terminal bud of plumule is thus protected.
In the vegetative terminal bud or mixed bud there are 3 kinds of scales. An outer scale wraps around the whole bud, in which there are 2 other types of scales, one encloses the young foliage leaf , and the other contains the other parts of the bud. In axial of scale c is the axillary bud d. This pattern is repeated again and again.
3. The young foliage leaf is wrapped in its scale and both are turned in the same direction. The morphological nature of this scale awaits further investigation.
4. One very peculiar feature is that the flower bud appears to be formed not in the axil but on the dorsal side of the leaf base.
The bud of the lotus plant appears atypical and bizarre.