Seasonality and growth rings in lianas of Bignoniaceae

Abstract

Lianas are one of the most important components of tropical forest, and yet one of the most poorly known organisms. Therefore, our paper addresses questions on the environmental and developmental aspects that influence the growth of lianas of Bignoniaceae, tribe Bignonieae. In order to better understand their growth, we studied the stem anatomy, seasonality of formation and differentiation of secondary tissues, and the influence of the cambial variant in xylem development on a selected species: Tynanthus cognatus. Afterwards, we compared the results found in T. cognatus with 31 other species of Bignonieae to identify general patterns of growth in lianas of this tribe. We found that cambial activity starts toward the end of the rainy season and onset of the dry season, in contrast to what is known for tropical trees and shrubs. Moreover, their pattern of xylem formation and differentiation is strongly influenced by the presence of massive wedges of phloem produced by a variant cambium. Thus, the variant cambium is the first to commence its activity and only subsequently does cambial activity progress towards the center of the regular region, leading to the formation of confluent growth rings. In summary, we conclude that: the cambium responds to environmental changes; the xylem growth rings are annual and produced in a brief period of about 2 months, something that may explain why lianas possess narrow stems; and furthermore, phloem wedges greatly influence cambial activity.

Hydraulic architecture of lianas in a semiarid climate: efficiency or safety?

“…We attributed the weak correlation between N and Kp to the vessel dimorphism described by Carlquist (1985) in lianas. The vessels in lianas tend to be very wide or very narrow (Carlquist 1985;Lima et al 2010;Carlquist 2012;Rosell & Olson 2014) in contrast to the normal distribution expected for a population of cells (Carlquist 1985). In short, the simultaneous presence of wide and narrow vessels (vessel dimorphism) assures both efficiency and safety of hydraulic conductivity in lianas (Gutiérrez et al 2009).…”

Cambial Variants in the Family Menispermaceae in Taiwan

“…If xylem embolization occurs, smaller vessels are used for hydraulic conduction. This alternative function regarding vessel dimorphism simultaneously favors the efficiency and safety of water conduction [22]. With the exception of Cissampelos pareira var.…”

Chemical review and studies related to species from the genus Tynanthus (Bignoniaceae)

“…Lima, Pace and Angyalossy (2010), who studied issues concerning environmental and morphoanatomical aspects, especially those influencing vine growth, based their work on the characteristics of T. cognatus, and compared them to 31 other Bignonieae species. Thus, the stem anatomy, the seasonality of the formation and differentiation of secondary tissues and the influence on the change rate in xylem development were studied this species in order to identify general growth standards in vines from this tribe.…”