Origin of successive cambia on stem in three species of Menispermaceae

Abstract

-(Origin of successive cambia on stem in three species of Menispermaceae). The lianas observed in this study, Abuta convexa (Vell.) Diels, Abuta imene (Mart.) Eichler, and Chondrodendron platiphyllum (A. St.-Hil.) Miers, all have successive cambia in their stems. The terminology applied to stem histology in species with successive cambia is as diverse as the interpretations of the origins of this cambial variant. Therefore, this study specifi cally investigates the origin of successive cambia through a developmental analysis of the above-mentioned species, including an analysis of the terminology used to describe this cambial variation. For the fi rst time, we have identifi ed several developmental stages giving rise to the origins of successive cambia in this family. First, the pericycle originates in 1-3 layers of conjunctive tissue. After the differentiation of the fi rst ring, the conjunctive tissue undergoes new divisions, developing approximately 10 rows of parenchyma cells. In the middle portion, a layer of sclereids is formed, again subdividing the conjunctive tissue into two parts: internal and external. New cambia originate in the internal part, from which new secondary vascular strands will originate, giving rise to the second successive vascular ring of the stem. The external part remains parenchymatous during the installation of the second ring and will undergo new periclinal division, repeating the entire process. New cambia will originate from the neoformed strands, which will form only rays. In the literature, successive cambia are formed by a meristem called "diffuse lateral meristem." However, based on the species of Menispermaceae studied in this report, it is demonstrated that the diffuse lateral meristem is the pericycle itself.Key words -Abuta, cambial variant, Chondrodendron, development, liana RESUMO -(Origem dos câmbios sucessivos em caule de três espécies de Menispermaceae). As lianas observadas neste estudo, Abuta convexa (Vell.) Diels, Abuta imene (Mart.) Eichler e Chondrodendron platiphyllum (A. St.-Hil.) Miers, possuem câmbios sucessivos em seus caules. A terminologia aplicada à histologia de caules de espécies com câmbios sucessivos é tão diversa quanto as interpretações das origens dessa variação cambial. O objetivo deste estudo é investigar a origem dos câmbios sucessivos através de uma análise do desenvolvimento nas espécies supracitadas, incluindo uma análise da terminologia utilizada para descrevê-los. Diversos estágios do desenvolvimento que originam os câmbios sucessivos em Menispermaceae foram constatados. Inicialmente, o periciclo forma de 1 a 3 camadas de tecido conjuntivo. Depois da diferenciação do primeiro anel, o tecido conjuntivo divide-se novamente, desenvolvendo cerca de 10 fi leiras de células parenquimáticas. Na porção mediana forma-se um anel de esclereídes, subdividindo o tecido conjuntivo em duas partes. A parte mais interna (tecido conjuntivo interno) forma novos câmbios, que, por sua vez, originam os novos cordões vasculares secundários, formando, ...

Structure and ontogeny of successive cambia in Tetrastigma (Vitaceae), the host plants of Rafflesiaceae

“…As for origin, they are always formed externally to the original vascular cylinder. The most common origin is from parenchyma of the outermost portion of the vascular cylinders, which in roots is unanimously recognized as the pericycle, while in stems it is recognized either as the pericycle or sometimes the cortex by those authors who do not believe in its presence there (Eames & McDaniels, , Tamaio et al, ; Terrazas et al, , Cunha Neto et al ). However, successive cambia can also derive from phloem parenchyma cells of the nonconducting secondary phloem, as shown in some Leguminosae (Nair & Mohan‐Ram, ; Dias‐Leme, ) or cortical cells beyond the limits of the vascular cylinder (Rajput et al, ).…”

Cambial Variants in the Family Menispermaceae in Taiwan

“…In these three species, approximately 8 -9 collateral vascular bundles (cvb) were present, and each collateral vascular bundle developed 1 -3 split strips (Figure 1(f); Figure 2(a) and Figure 2(b); arrows). A mature stem of Ungulipetalum filipendulum (Menispermaceae) was identified based on parenchyma proliferation [23]. The trait of 1 -3 split strips is related to the proliferation of non-lignified parenchyma.…”

Development of lateral meristem and pattern of secondary growth in stems and roots of Spinacia oleracea Linn (Amaranthaceae)

“…MENEZES et al (2005) introduced a new interpretive proposal for the primary thickening meristem, describing the PTM as the pericycle in a meristematic phase, together with the endodermis and its derivatives. On the other hand TAMAIO et al (2009) concluded that meristematic conjunctive tissue of the Menispermaceae and the PTM are the same structure with different names.…”

“…Yet, there is not only controversy about terminology, but also about the origin(s) of the successive cambia and their cambial derivatives as well as about the underlying growth patterns. Different ontogenetic interpretations have led to the distinct terminology (STE- VENSON & POPHAM 1973;MIKESELL & POPHAM 1976;MIKESELL 1973MIKESELL , 1979YARROW & PO-PHAM 1981;CARLQUIST 1988CARLQUIST , 2004CARLQUIST , 2007bRAJPUT et al 2009a;TAMAIO et al 2009).…”