Speaker
Description
- Introduction
Iron is an essential micronutrient for plants with a very important role in their metabolism. 80-90% of Fe is located in chloroplasts. Therefore, any imbalance in foliar Fe homeostasis will affect chlorophyll synthesis and the photosynthetic apparatus [1]. However, excess Fe can cause phytotoxicity, especially in waterlogged soils, through the generation of reactive oxygen species (ROS), such as the hydroxyl radical (.OH), which can cause damage at the cellular level [2]. - Material and Methods
In this work, we proposed to reduce the application of Fe chelates in the fertirrigation of mandarin trees of the “Nadorcott” variety, grafted on Macrophylla. The study was carried out in Pozo Estrecho (Cartagena, Spain), in a soil containing a low organic matter content, basic pH and high levels of Fe (about 30 g/Kg soil) owned by a private company, dedicated to the production of citrus. We proposed to reduce the application of Fe chelates by 25% and 50% in relation to the conventional fertirrigation regime applied by the company. After 5 months of applying these reductions, an analysis of mineral nutrients in soil, roots and leaves was carried out. Likewise, the contents of chlorophyll, flavonols and anthocyanins, chlorophyll fluorescence parameters, lipid peroxidation (marker of membrane damage) and peroxidase activity (POX), as a biochemical marker of Fe, were determined in the leaf. Finally, the effect on production and fruit quality was also determined. -
Results and Discussion
The results showed that the reduction in the application of Fe led to a decrease in its levels in the soil, without affecting the contents in roots and leaves, in relation to control plants (conventional fertirrigation). On the other hand, the Fe reduction treatments did not affect the leaf chlorophylls, flavonols and anthocyanins contents. When analyzing the chlorophyll fluorescence parameters, no changes were observed in the photochemical quenching parameters [Fv/Fm; Y(II) and qP], but an increase in the non-photochemical quenching parameters (qN, NPQ) took place, which can be considered as a defense mechanism of the chloroplasts. On the other hand, the electron transport rate (ETR) in the chloroplast remained unchanged. This is very interesting, since it must be taken into account that Fe takes part of numerous electronic transporters in the photosynthetic electronic transport chain of the chloroplast [3] and that a reduction in Fe fertilization does not negatively affect ETR, which indicates that the company can reduce the application of Fe chelates.
The reduction in Fe fertilization did not affect the stress state of the trees, as reflected by the data on lipid peroxidation and leaf POX activity, a biochemical Fe indicator. Finally, the production and quality data were not affected by the effect of the reduction in Fe fertilization. Altogether, our results support the viability of the reduction in the Fe application without negatively affecting either the physiology of mandarin trees or their production. -
References
[1 ]Zahra N; Bilal Hafeez M; Wahid A; Kanval S; Hasanuzzaman M (2021) Fe toxicity in plants: Impacts and remediation. Physiol Plant. 173, 201–222.
[2]Halliwell B, Gutteridge JMC (2003) Free Radicals in Biology and Medicine. Third Edition, Oxford University Press Inc, New York, ISBN 0 19 850044 0.
[3] Taiz L, Zeiger E (2010) Plant Physiology. Sinauer Associates Inc.,U.S.; 5th edition. ISBN-13 : 978-0878935659
Project Financed by the Center for Technological Development and Innovation (CDTI)
| Keywords | Iron nutrition, sustainable agriculture, plant stress, photosynthesis, plant production |
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