Bicarbonate rather than high pH in growth medium induced Fe-deficiency chlorosis in dwarfing rootstock quince A (Cydonia oblonga Mill.) but did not impair Fe nutrition of vigorous rootstock Pyrus betulifolia

Yanyan Zhao; Yinglong Chen; Songzhong Liu; Fei Li; Mingde Sun; Zhenxu Liang; Zhi Sun; Futong Yu; Zed Rengel; Haigang Li

doi:10.3389/fpls.2023.1237327

Bicarbonate rather than high pH in growth medium induced Fe-deficiency chlorosis in dwarfing rootstock quince A (Cydonia oblonga Mill.) but did not impair Fe nutrition of vigorous rootstock Pyrus betulifolia

Front Plant Sci. 2023 Aug 24:14:1237327. doi: 10.3389/fpls.2023.1237327. eCollection 2023.

Authors

Yanyan Zhao^{1

2

3}, Yinglong Chen³, Songzhong Liu⁴, Fei Li^{1

2}, Mingde Sun⁴, Zhenxu Liang⁴, Zhi Sun^{1

2}, Futong Yu⁵, Zed Rengel^{3

6}, Haigang Li^{1

2}

Affiliations

¹ Inner Mongolia Key Laboratory of Soil Quality and Nutrient Resources, Key Laboratory of Agricultural Ecological Security and Green Development at Universities of Inner Mongolia Autonomous Region, Inner Mongolia Agricultural University, Hohhot, China.
² Key Laboratory of Agricultural Ecological Security and Green Development at Universities of Inner Mongolia Autonomous Region, Inner Mongolia Agricultural University, Hohhot, China.
³ The UWA Institute of Agriculture, & School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia.
⁴ Institute of Forestry & Pomology, Beijing Academy of Agriculture & Forestry Sciences, Beijing Engineering Research Center for Deciduous Fruit Trees, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, Beijing, China.
⁵ College of Resources and Environmental Sciences, China Agricultural University, Beijing, China.
⁶ Institute for Adriatic Crops and Karst Reclamation, Split, Croatia.

Abstract

Introduction: Quince A (Cydonia oblonga Mill.), a typical dwarfing rootstock in pear cultivation, is susceptible to iron (Fe) deficiency in calcareous soils. The aim of this study was to compare the strategies in Fe uptake and utilization in dwarfing rootstock quince A (low Fe efficiency) versus a typical vigorous rootstock Pyrus betulifolia (PB) with high Fe efficiency.

Methods: Quince A and PB were grown in nutrient solution (pH 6.3) for 4 weeks followed by three pH treatments: pH6.3, pH8.3a (adjusted with hydroxide) and pH8.3b (adjusted with bicarbonate). The Fe uptake and utilization indicators of the rootstocks were assessed at the onset of chlorosis symptoms (after 58 days of treatments).

Results and discussion: In contrast to PB, quince A exhibited Fe deficiency chlorosis under bicarbonate (pH8.3b). Bicarbonate stimulated the root proton secretion, inhibited root growth and ferric chelate reductase (FCR) activity in both PB and quince A, whereas high pH without bicarbonate (pH8.3a) stimulated only root proton release. Both species accumulated more Fe in roots under high pH treatments than under pH6.3, resulting in Fe sufficiency in leaves. Both high pH treatments increased the activity of leaf FCR in PB and quince A. However, extractable Fe(II) concentration in leaves was increased by high pH treatments in PB only. This study demonstrated that depressed Fe(III) reduction in leaves caused by bicarbonate rather than high pH explained Fe deficiency in quince A grown in bicarbonate-containing medium.

Keywords: Fe deficiency; Pyrus betulifolia; bicarbonate; high pH; pear rootstock; quince A.

Grants and funding

This study was supported by Double First-Class Financial Capital in China (Grant No. NDYB2018-4/NDYB2019-4), Science and Technology Innovation Capacity Building Program of Beijing Academy of Agriculture and Forestry Sciences (Grant No. KJCX20200114), Scientific Research Start-up Fund of the Autonomous Region Human Resources and Social Security Department in 2018 (HL), the Project of Grassland Talent (HL) and Australian Research Council (Grant No. FT210100902, YC).