Comparative study on the secondary xylem and phloem formation in three varieties of Mucuna pruriens (L.) DC (Fabaceae)

IF 1.7 4区生物学 Q3 ECOLOGY

Flora Pub Date : 2025-02-05 DOI:10.1016/j.flora.2025.152682

Meera Rami , Rajaram V. Gurav , Swaroopsingh Gaikwad , Kishore S. Rajput

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Abstract

The structure and composition of the main stem and the increase in stem diameter were compared histologically in Mucuna pruriens (L.) DC. var. pruriens, M. pruriens var. hirsuta (Wight & Arn.) Wilmot-Dear and M. pruriens var. utilis (Wall. ex Wight) Baker ex Burck. Initially, all three varieties showed regular secondary growth like most eudicots, the vascular cambium divided bi-facially and deposited secondary xylem centripetally and phloem centrifugally. The secondary xylem showed typical anatomical features characteristic of the lianescent habit, such as the co-occurrence of dimorphic (narrow and wide) vessels and an abundance of thin-walled, nonlignified parenchyma cells. After a certain period of secondary growth, earlier formed axial parenchyma began to dedifferentiate into interxylary phloem in all three varieties investigated. The number of sieve elements increased gradually with the increase in age. However, the thick stems of M. pruriens var. hirsuta showed simultaneous differentiation of phloem on both centripetal and a centrifugal direction, which was exclusively observed in this variety. In thick stems, the formation of vascular cylinders external to the regular phloem (neoformed vascular cylinders) was observed in M. pruriens var. hirsuta (8 mm) and M. pruriens var. pruriens (14 mm). At the same time, they were found absent in M. pruriens var. utilis (10 mm). Ontogenetically, the initiation of these vascular cylinders was unique and it was initiated from the dilating phloem ray cells and pericyclic parenchyma cells. The vascular cylinders developed from the dilating ray cells were irregularly (tangentially or diagonally) oriented while cylinders originating from pericyclic parenchyma had regular polarity (phloem externally and xylem internally). The initiation of the interxylary phloem and the structure of the secondary xylem of both regular and neoformed external vascular cylinders are elucidated in detail.

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3个麻豆品种次生木质部和韧皮部形成的比较研究直流(豆科)

从组织学上比较了麻豆（Mucuna pruriens， L.）主茎的结构和组成以及茎粗的增加。直流。变种pruriens， m.p ururiens变种hirsuta (wright &；在攻击)。威尔莫特-迪尔和M.普鲁里安。前怀特贝克前伯克。初始阶段，三个品种均表现出与大多数异构体一样的有序次生生长，维管形成层呈双面分裂，次生木质部向心分裂，韧皮部向心分裂。次生木质部表现出典型的线状结构特征，如双形（窄和宽）血管的共存和大量薄壁、非木质化的薄壁组织细胞。经过一定时期的次生生长后，早期形成的轴向薄壁组织开始脱分化为木质部韧皮部。随着龄期的增加，筛元数量逐渐增加。而粗茎的韧皮部在向心和离心方向上同时分化，这是该品种所特有的现象。在粗茎中，在正常韧皮部外有维管柱形成（新维管柱形成）的有毛毛毛蕊毛梗（8 mm）和毛蕊毛梗（14 mm）。与此同时，在10 mm的褐毛杆菌中没有发现它们。在个体发育上，这些维管柱的起始是独特的，它起源于扩张的韧皮部射线细胞和周环薄壁细胞。由扩张的射线细胞发育而来的维管柱取向不规则（切线或对角），而由周环薄壁组织发育而来的维管柱极性规则（韧皮部向外，木质部向内）。详细阐述了正常和新生外维管柱的木质部的形成和次生木质部的结构。

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来源期刊

Flora 生物-植物科学

CiteScore

3.30

自引率

10.50%

发文量

130

审稿时长

54 days

期刊介绍： FLORA publishes original contributions and review articles on plant structure (morphology and anatomy), plant distribution (incl. phylogeography) and plant functional ecology (ecophysiology, population ecology and population genetics, organismic interactions, community ecology, ecosystem ecology). Manuscripts (both original and review articles) on a single topic can be compiled in Special Issues, for which suggestions are welcome. FLORA, the scientific botanical journal with the longest uninterrupted publication sequence (since 1818), considers manuscripts in the above areas which appeal a broad scientific and international readership. Manuscripts focused on floristics and vegetation science will only be considered if they exceed the pure descriptive approach and have relevance for interpreting plant morphology, distribution or ecology. Manuscripts whose content is restricted to purely systematic and nomenclature matters, to geobotanical aspects of only local interest, to pure applications in agri-, horti- or silviculture and pharmacology, and experimental studies dealing exclusively with investigations at the cellular and subcellular level will not be accepted. Manuscripts dealing with comparative and evolutionary aspects of morphology, anatomy and development are welcome.