Stem vascular architecture in the rattan palmCalamus(Arecaceae–Calamoideae–Calaminae)

Abstract

Climbing stems in the rattan genus Calamus can reach lengths of well over 100 m, are long-lived, and yet their vascular tissue is entirely primary. Such a combination suggests that stem vasculature is efficient and resistant to hydraulic disruption. By means of an optical shuttle and video recording of sequential images we analyzed the stem of a cultivated species. The stem has vascular features that are unusual compared with those in arborescent palms and seemingly inefficient in terms of long-distance water transport. Axial bundles are discontinuous basally because leaf traces, when followed downwards, always end blindly below. Furthermore, there is no regular distal branching of each leaf trace at its level of departure into a leaf, so that neither a continuing axial bundle nor bridges to adjacent axial bundles are produced as in the standard palm construction. Instead, the axial bundles in the stem periphery are connected to leaf traces and to each other by narrow and irregular transverse or oblique commissures that are not the developmental homologues of bridges. As in other palms, metaxylem within a leaf trace is not continuous into the leaf so that the only connection to a leaf is via protoxylem. Within the stem, protoxylem (tracheids) and metaxylem (vessels) are never contiguous, unlike in other palms, which suggests that water can only move from metaxylem to protoxylem, and hence into the leaf, across a hydraulic resistance. We suggest that this minimizes cavitation of vessels and/or may be associated with an unknown mechanism that refills embolized vessels. Also, the metaxylem can be significant in stem water storage in the absence of abundant ground parenchyma.

Plant Species Composition and Their Conspecific Association in Natural Tropical Rainforest, South Papua

“…This species is not distributed widely, but this species tend to grow in assemblage as the density about 3000 ind ha -1 . The stem of rattans can grow in any direction with hundreds of meters long as long as the stem can reach sunlight by using leaf-climbers as morphological support (Tomlinson et al, 2001) There are many types of vines, one of which is Derris ellipticawhere this species is the most dominant vine categorized as small plant (H. Zhu, 2008). This species was found in 30 % of this forest (frequency is 0.3).…”

A revised delimitation of the rattan genus Calamus (Arecaceae)

“…The expanded concept of Calamus is also consistent with evidence from root (Seubert 1996) and leaf (Tomlinson et al 2011) anatomical studies. Furthermore, Calamus sensu lato appears to be unique among climbing palm groups in its stem vascular anatomy, particularly with respect to xylem construction (Tomlinson et al 2001, Fisher et al 2002, Tomlinson & Spangler 2002, Tomlinson et al 2011.…”

Is the secondary thickening in palms always diffuse?

“…An extensive research done by Zimmermann and Tomlinson on palm stem anatomy is highlighted in the literature (Zimmermann and Tomlinson 1965, 1968, 1974, Tomlinson and Zimmernmann 1966, Zimmermann et al 1982, Tomlinson et al 2001, Tomlinson and Spangler 2002, Tomlinson 2006. Palms possess a lateral meristem near the stem apex termed primary thickening meristem (PTM, Helm 1936), but referred as "meristematic cap" by Tomlinson (1968, 1974).…”