Differential responses in pear and quince genotypes induced by Fe deficiency and bicarbonate

Summary

This study investigated differential responses to iron deficiency induced by bicarbonate stress in pear and quince genotypes with contrasting chlorosis tolerance. Tolerant and susceptible genotypes showed different reorganisation of the photosynthetic apparatus under bicarbonate-induced iron stress, with tolerance positively correlated to activation of Strategy I iron acquisition mechanisms (Fe3+-chelate reductase and H+-ATPase activities). The findings demonstrate that bicarbonate-induced iron deficiency more closely mimics field conditions than total iron depletion, revealing genotype-specific physiological and biochemical adaptations.

Regional applicability

Iron deficiency chlorosis and bicarbonate-induced stress are agronomic challenges in calcareous soils, which occur in parts of the United Kingdom and widely across Europe. The identified Strategy I mechanisms and genotype-specific responses could inform rootstock selection for pear and quince production in high-pH soils, though field validation in UK conditions would be needed.

Key measures

Pigment content (HPLC), protein-pigment complexes (gel blot), photosystem structural organisation, photosynthetic electron transport rate in isolated thylakoids, Fe3+-chelate reductase activity, H+-ATPase activity

Outcomes reported

The study compared physiological and biochemical responses to iron deficiency and bicarbonate stress in pear (Pyrus communis cv. Conference) and quince clones with different chlorosis tolerance levels, measuring pigment content, photosystem organisation, electron transport rates, and iron uptake enzyme activities (Fe3+-chelate reductase and H+-ATPase).

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