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Sensitivity of chickpea and faba bean to root‐zone hypoxia, elevated ethylene, and carbon dioxide
- Munir, Rushna, Konnerup, Dennis, Khan, Hammad A., Siddique, Kadambot H.M., Colmer, Timothy D.
- Plant, cell and environment 2019 v.42 no.1 pp. 85-97
- Cicer arietinum, Vicia faba, carbon dioxide, chickpeas, death, ethylene, faba beans, flooded conditions, hypoxia, oxygen, porosity, rhizosphere, root tips, soil, sugars
- During soil waterlogging, plants experience O₂ deficits, elevated ethylene, and high CO₂ in the root‐zone. The effects on chickpea (Cicer arietinum L.) and faba bean (Vicia faba L.) of ethylene (2 μL L⁻¹), CO₂ (2–20% v/v) or deoxygenated stagnant solution were evaluated. Ethylene and high CO₂ reduced root growth of both species, but O₂ deficiency had the most damaging effect and especially so for chickpea. Chickpea suffered root tip death when in deoxygenated stagnant solution. High CO₂ inhibited root respiration and reduced growth, whereas sugars accumulated in root tips, of both species. Gas‐filled porosity of the basal portion of the primary root of faba bean (23%, v/v) was greater than for chickpea (10%), and internal O₂ movement was more prominent in faba bean when in an O₂‐free medium. Ethylene treatment increased the porosity of roots. The damaging effects of low O₂, such as death of root tips, resulted in poor recovery of root growth upon reaeration. In conclusion, ethylene and high CO₂ partially inhibited root extension in both species, but low O₂ in deoxygenated stagnant solution had the most damaging effect, even causing death of root tips in chickpea, which was more sensitive to the low O₂ condition than faba bean.