Growth and photosynthetic response of young ‘Navelina’ trees budded on to eight citrus rootstocks in response to iron deficiency

Abstract

Citrus trees growing in the Mediterranean region suffer from iron (Fe) deficiency because of the presence of high levels of carbonate ions in calcareous soils. In this context we have evaluated the effects of different citrus rootstocks on photosynthetic capacity and plant development of young ‘Navelina’ orange trees under Fe deprived conditions. Leaf number, shoot length, plant dry mass, leaf chlorophyll (Chl) concentration, net photosynthetic rate (P _N), stomatal conductance (g_S), leaf transpiration rate (E), intercellular CO₂ concentration (C_i) and photosynthetic water use efficiency (WUE) of ‘Navelina’ orange scion budded on to eight citrus rootstocks with different agronomic characteristics were investigated. Significant decreases in leaf number, shoot length and plant dry mass under high pH conditions were observed. Plants on Tuzcu 31 31 and Gou Tou sour orange rootstocks were the least affected in terms of plant growth. The highest reduction in the leaf Chl content was observed in (-)Fe plants of Navelina on local trifoliate and C-35 citrange. These rootstocks also had significantly reduced PN, gS and E rates in the (-)Fe treatment. Shoots budded on Tuzcu 31 31 and Gou Tou sour oranges were the least affected by the induced Fe deficiency.

Keywords:

• abiotic stress
• gas exchange
• growth
• SPAD
• water use efficiency

Acknowledgements

This research was supported by the grant from the Çukurova University, Scientific Research Projects Coordinating Office (project CU-BAP-ZF2010YL30). The authors are grateful to Dr Richard Rosecrance for critical reading and language correction of the manuscript.