Influence of Colder Temperature on the Axial and Radial Parenchyma Fraction of Quercus ciliaris C.C.Huang &amp; Y.T.Chang Wood and Its Relationship with Carbohydrate Reserve (NSC)

Xijin Zhang,Kun Song,Xingli Xia,Dan Wu,Qingyao Li,Faguang Pu,Mingyang Chang

doi:10.3390/f13020169

Abstract

Parenchyma in the secondary xylem comprises the main tissue for the storage of non-structural carbohydrates (NSC) in woody plants. Across species, the amount of parenchyma depends on the general environment of the distribution area and determines to a large extent the NSC storage. However, little information is available on the relationship between parenchyma fractions, NSC storage, and the environmental influences within individual species. This information is crucial to assessing the adaptive capacities of tree populations in the context of increasing the frequency and severity of stress-inducing events. In this study, parenchyma fractions and NSC concentrations of the secondary xylem in trunks of a subtropical evergreen oak (Quercus ciliaris C.C.Huang & Y.T.Chang) were quantified along an elevational gradient from 700 m to 1200 m a.s.l. in eastern China. Air temperatures within the distribution area correlated with altitude were recorded. The results showed that the total parenchyma fractions did not covary with the colder temperatures. However, axial parenchyma fractions were lower with a colder climate, while the fractions of multiseriate rays and total ray parenchyma were higher. Higher concentrations of starch and NSC were significantly associated with larger axial parenchyma fractions. The sugar concentration displayed no significant relationship with parenchyma fractions. These findings suggest that the total parenchyma fractions in secondary xylem do not increase in response to a colder climate, while colder temperatures drive changes in the composition of parenchyma for Q. ciliaris.

Highlights

Introduction iationsIt is well known that the majority of a tree’s biomass is contained within the secondary xylem of the stems [1,2,3]
We employed a species of evergreen oak to investigate the variations in parenchyma fraction along a temperature gradient, along with the relationships between the parenchyma fraction and the nonstructural carbohydrates (NSC) concentration at the end of a growing season in a northern subtropical region
The fraction of total parenchyma did not increase with colder temperatures

Summary

Introduction

It is well known that the majority of a tree’s biomass is contained within the secondary xylem of the stems [1,2,3]. These woody tissues are generally composed of vessels (and, in some cases, tracheids), fibers, and parenchyma. The relationship between the properties and functions of woody tissue components, such as vessels and fibers are well studied [6,7,8,9], the relationships between the properties and functions of parenchyma are much less well understood [10].

Methods

Results

Discussion

Conclusion