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Leaf angle responds to nitrogen supply in eucalypt seedlings. Is it a photoprotective mechanism?

journal contribution
posted on 2023-05-16, 18:48 authored by Dugald CloseDugald Close, Beadle, CL
We examined the adjustment of leaf angle (L θ) and foliar chlorophyll and xanthophyll chemistry in Eucalyptus nitens (Deane and Maiden) Maiden seedlings maintained in various nitrogen (N)-supply treatments over a 6-month period. Adjustment of L θ toward the vertical was greatest under conditions of foliar N deficiency and became incrementally more horizontal with increasing foliar N concentration. Photochemical efficiency (F v/F m) and quantum yield were lower in seedlings with low foliar N (low-N seedlings) in winter, but not in autumn. Low-N seedlings generally had low area-based chlorophyll concentrations and high xanthophyll-cycle conversion ratios, particularly during months of low temperature. Under mild temperature conditions, high concentrations of zeaxanthin and antheraxanthin were associated with lower electron transport rates (ETR). Incident light, F v/F m, ETR and total chlorophyll concentration were negatively correlated with L θ, with horizontal leaf orientation measured as 0° and vertical leaf orientation as 90°. Xanthophyll conversion ratio was positively correlated with L θ. Adjustments in L θ may play a role in photoprotection of E. nitens seedlings by assisting the leaf to balance its utilization and dissipation of energy. © 2006 Heron Publishing.

History

Publication title

Tree Physiology

Volume

26

Issue

6

Pagination

743-748

ISSN

0829-318X

Department/School

School of Natural Sciences

Publisher

Heron Publishing

Place of publication

Canada

Repository Status

  • Restricted

Socio-economic Objectives

Hardwood plantations

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