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Systemic regulation of photosynthetic capacity and high-light tolerance in sorghum seedlings

Date

2011-03

Authors

Chow, Wah Soon
Jiang, Chuang-Dao
Wang, Xin
Gao, Hui-Yuan
Shi, Lei

Journal Title

Journal ISSN

Volume Title

Publisher

American Society of Plant Biologists

Abstract

Leaf anatomy of C3 plants is mainly regulated by a systemic irradiance signal. Since the anatomical features of C4 plants are different from that of C3 plants, we investigated whether the systemic irradiance signal regulates leaf anatomical structure and photosynthetic performance in sorghum (Sorghum bicolor), a C4 plant. Compared with growth under ambient conditions (A), no significant changes in anatomical structure were observed in newly developed leaves by shading young leaves alone (YS). Shading mature leaves (MS) or whole plants (S), on the other hand, caused shade-leaf anatomy in newly developed leaves. By contrast, chloroplast ultrastructure in developing leaves depended only on their local light conditions. Functionally, shading young leaves alone had little effect on their net photosynthetic capacity and stomatal conductance, but shading mature leaves or whole plants significantly decreased these two parameters in newly developed leaves. Specifically, the net photosynthetic rate in newly developed leaves exhibited a positive linear correlation with that of mature leaves, as did stomatal conductance. In MS and S treatments, newly developed leaves exhibited severe photoinhibition under high light. By contrast, newly developed leaves in A and YS treatments were more resistant to high light relative to those in MS- and S-treated seedlings. We suggest that (1) leaf anatomical structure, photosynthetic capacity, and high-light tolerance in newly developed sorghum leaves were regulated by a systemic irradiance signal from mature leaves; and (2) chloroplast ultrastructure only weakly influenced the development of photosynthetic capacity and high-light tolerance. The potential significance of the regulation by a systemic irradiance signal is discussed.

Description

Keywords

sorghum, photosynthetic rate, photoinhibition, photochemical efficiency of photosystem II, systemic regulation

Citation

Source

Plant Physiology 155 (2011): 1416–1424

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

DOI

10.1104/pp.111.172213

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