Physiological, morphological and anatomical leaf traits variation across leaf development in 'Corylus avellana'

Mirko Umberto Granata,Loretta Gratani,Francesco Bracco,Rosangela Catoni

doi:10.5209/mbot.62325

Abstract

The study analyzed the variations of physiological, morphological and anatomical leaf traits during its development in Corylus avellana L. saplings. Three different phases were identify during leaf development: the first phase (hereafter IP) considered in the developing leaves, the second phase (IIP) in the mature green leaves and the third phase (IIIP) in the senescent leaves. In particular, variations in parameters estimated from the photosynthetic light response curves, in chlorophyll fluorescence variables and in morphological leaf traits were analyzed during the three phases. The principal component analysis (PCA) carried out using all the considered morphological characters (leaf mass per area - LMA, and leaf tissue density - LTD) and physiological traits (the maximum net photosynthetic rates - ANmax, dark respiration rates - RD, light compensation point - LCP, light saturation point – LSP, maximum quantum yield - ɸmax, fluorescence-based maximum quantum yield of PSII photochemistry - Fv/FM and effective quantum yield of PSII photochemistry - ɸPSII) showed a complete separation among the considered phases. The results showed that the major differences occur between the phases IP and IIP. In particular, a greater variation was found for LMA, ANmax, RD. On the contrary a lower variation was observed for ɸmax which remain quite constant from IP to IIP indicating that chloroplasts present in juvenile leaves are fully functional.

Highlights

Leaf development comprises an important period of leaf lifetime (Miyazawa et al, 1998; 2003)
leaf mass per area (LMA) showed the lowest value in IP (3.3 ± 0.1 mg cm-2) increasing by more than
leaf tissue density (LTD) was 405 ± 13 mg cm-3 in IP increasing by 70% and 63% in IIP and IIIP, respectively

Summary

Introduction

Leaf development comprises an important period of leaf lifetime (Miyazawa et al, 1998; 2003). It is a genetically controlled process (Tardieu et al, 1999; Sugiyama, 2005; Varone & Gratani, 2009) which depends on several environmental conditions, such as photon flux density, air temperature and soil water status (Cookson et al, 2005; Sui et al, 2012). The first phase concerns leaf blade formation. In this phase leaf is a net carbonimporting structure with low net assimilation rates (AN) and high dark respiration rates (RD) (Cai et al, 2005) to sustain the construction cost of leaf structural compounds process (Armstrong et al, 2006).

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