Comparative anatomy of leaf petioles in temperate trees and shrubs: the role of plant size, environment and phylogeny

Abstract

Background and Aims Petioles are important plant organs connecting stems with leaf blades and affecting light-harvesting ability of the leaf as well as transport of water, nutrients and biochemical signals. Despite the high diversity in petiole size, shape and anatomy, little information is available about their structural adaptations across evolutionary lineages and environmental conditions. To fill our knowledge gap, we investigated the variation of petiole morphology and anatomy of mainly European woody species to better understand drivers of internal and external constraints in an evolutionary context. Methods We studied how petiole anatomical features differed according to whole-plant size, leaf traits, thermal and hydrological conditions, and taxonomical origin in 95 shrubs and trees using phylogenetic distance-based generalized least squares models. Key Results Two major axes of variation were related to leaf area and plant size. Larger and softer leaves are found in taller trees of more productive habitats. Their petioles are longer, with a circular outline and anatomically characterized by the predominance of sclerenchyma, larger vessels, interfascicular areas with fibers and indistinct phloem rays. In contrast, smaller and tougher leaves are found in shorter trees and shrubs of colder or drier habitats. Their petioles have terete outline, phloem composed of small cells and radially arranged vessels, fiberless xylem and lamellar collenchyma. Individual anatomical traits were linked to different internal and external drivers. The petiole length and vessel diameter increase with enlarging leaf blade area. Collenchyma becomes absent with increasing temperature, and petiole outline becomes polygonal with increasing precipitation. Conclusions We conclude that species temperature and precipitation optima, plant height, leaf area and thickness exerted a significant control on petiole anatomical and morphological structures not confounded by phylogenetic inertia. Species with different evolutionary histories but similar thermal and hydrological requirements have converged to similar petiole anatomical structures.

Allometric relationships between leaf and petiole traits across 31 floating-leaved plants reveal a different adaptation pattern from terrestrial plants

“…The allometric scaling in leaf area correlated strongly with petiole/stem transverse area, in agreement with previous studies ( Gleason et al , 2018 ; Zhong et al , 2019 ; Filartiga et al , 2022 ). Although Wen et al (2020) stated that allometry should be considered as an adaptation of hydraulic processes in terrestrial plants, we argue that the clear pattern described by allometric equations for these aquatic plants might not only be constrained by hydraulic process, but also related to other biological processes.…”

“…A recent study on terrestrial shrubs and trees also discovered no phylogenetic conservation on these petiole traits (e.g. petiole transverse area, xylem diameter) ( Filartiga et al , 2022 ). The significant scaling relationships between total stomatal area and petiole xylem (or vascular) area in floating-leaved plants did not change after considering phylogeny.…”

Deficit irrigation combined with nitrogen application in the early growth stage of sugar beet increases the production capacity of canopy and avoids yield loss

“…In addition, the petioles were significantly affected by water and N treatments. High N level affects photosynthetic assimilates and water transport by mediating adaptive changes in petiole morphological (P SA ) and anatomical (MVB XW and MVB PW ) traits, which in turn positively affects yield 42 . The results of SEM also showed a significant positive effect of petiole traits on yield under the W and N treatments (Fig.…”

“…In addition, the petiole vascular tissue enhanced by N application can not only provide strong mechanical support for the leaves to keep upright and intercept light resources, 42 but also prevent water deficit-induced damage to parenchyma cells between petiole vascular bundles. 42,43 Δ 13 C indicates WUE of sugar beet more reliably than IWUE of leaves A previous study has shown that appropriate water deficit could increase crop WUE by increasing the cumulative effect of IWUE. 44 However, in this study, DI reduced IWUE by 6.4% compared to W1, while N application significantly improved IWUE (Fig.…”

Progression toward maximum leaf surface storage during the rainfall interception process

“…The high correlations between LIA i and ΔLIA max may be due to the relative stiffness of the petiole (Filartiga et al, 2022; Niklas, 1999; Wolff‐Vorbeck et al, 2022). A less stiff petiole would result in a larger LIA i as well as a larger maximum change.…”