Leaf Lateral Asymmetry in Morphological and Physiological Traits of Rice Plant.

Shen Yuan,Yong Li,Shaobing Peng,Keqiang Wu

doi:10.1371/journal.pone.0129832

Abstract

Leaf lateral asymmetry in width and thickness has been reported previously in rice. However, the differences between the wide and narrow sides of leaf blade in other leaf morphological and physiological traits were not known. This study was conducted to quantify leaf lateral asymmetry in leaf width, leaf thickness, specific leaf weight (SLW), leaf nitrogen (N) concentration based on dry weight (Nw) and leaf area (Na), and chlorophyll meter reading (SPAD). Leaf morphological and physiological traits of the two lateral halves of the top three leaves at heading stage were measured on 23 rice varieties grown in three growing seasons in two locations. Leaf lateral asymmetry was observed in leaf width, leaf thickness, Nw, Na, and SPAD, but not in SLW. On average, the leaf width of the wide side was about 17% higher than that of the narrow side. The wide side had higher leaf thickness than the narrow side whereas the narrow side had higher Nw, Na, and SPAD than the wide side. We conclude that the narrow side of leaf blade maintained higher leaf N status than the wide side based on all N-related parameters, which implies a possibility of leaf lateral asymmetry in photosynthetic rate in rice plant.

Highlights

Rice (Oryza sativa L.) is one of the most important staple foods in the world, providing 35– 60% of the dietary calories consumed by more than 3 billion people [1]
The absolute difference in leaf width between the wide and narrow sides was increasing as the leaf width increased (Fig 1)
We report that the leaf width of the wide side was about 17% higher than that of the narrow side across large number of rice varieties grown under different conditions

Summary

Introduction

Rice (Oryza sativa L.) is one of the most important staple foods in the world, providing 35– 60% of the dietary calories consumed by more than 3 billion people [1]. Increasing rice yields on existing land is a primary strategy for increasing rice production in order to meet the demand of growing population [2]. Rice leaves have many functions such as light interception, photosynthesis, and assimilate storage; leaf morphological and physiological traits have large effects on rice grain yield [3]. The optimum leaf length, width, thickness, angle, and area were considered in developing high-yielding rice varieties through ideotype breeding [4]. The varieties with high yield potential usually have leaves that were erect, short, narrow, thick, and dark green [5]. A thick leaf usually has higher chlorophyll, nitrogen (N), and photosynthetic enzymes content per unit leaf area [6,7]. There is a positive correlation between single-leaf net photosynthetic rate and leaf thickness in rice [8]. A thick leaf has less tendency to expand horizontally

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Conclusion