Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, 56124, Pisa, Italy.
Laboratory of Mycology, Department of Phytopathology, Benaki Phytopathological Institute, St. Delta 8, 14561, Kifisia, Greece.
Planta. 2019 Oct;250(4):1011-1032. doi: 10.1007/s00425-019-03220-4. Epub 2019 Jun 24.
In this review, emphasis is given to the most recent updates about morpho-anatomical, physiological, biochemical and molecular responses adopted by plants to cope with B excess. Boron (B) is a unique micronutrient for plants given that the range of B concentration from its essentiality to toxicity is extremely narrow, and also because it occurs as an uncharged molecule (boric acid) which can pass lipid bilayers without any degree of controls, as occurs for other ionic nutrients. Boron frequently exceeds the plant's requirement in arid and semiarid environments due to poor drainage, and in agricultural soils close to coastal areas due to the intrusion of B-rich seawater in fresh aquifer or because of dispersion of seawater aerosol. Global releases of elemental B through weathering, volcanic and geothermal processes are also relevant in enriching B concentration in some areas. Considerable progress has been made in understanding how plants react to B toxicity and relevant efforts have been made to investigate: (I) B uptake and in planta partitioning, (II) physiological, biochemical, and molecular changes induced by B excess, with particular emphasis to the effects on the photosynthetic process, the B-triggered oxidative stress and responses of the antioxidant apparatus to B toxicity, and finally (III) mechanisms of B tolerance. Recent findings addressing the effects of B toxicity are reviewed here, intending to clarify the effect of B excess and to propose new perspectives aimed at driving future researches on the topic.
在这篇综述中，重点介绍了植物为应对硼过量而采取的形态解剖学、生理学、生物化学和分子响应的最新进展。硼（B）是植物的一种独特的微量元素，因为硼的必需浓度到毒性浓度范围非常狭窄，而且因为它是以不带电荷的分子（硼酸）形式存在，这种分子可以毫无控制地穿过脂双层，就像其他离子营养物质一样。由于排水不良，硼在干旱和半干旱环境中经常超过植物的需求，并且在靠近沿海地区的农业土壤中，由于富含硼的海水侵入淡水含水层，或者由于海水气溶胶的分散，硼的浓度也会增加。通过风化、火山和地热过程释放的元素硼也会使某些地区的硼浓度增加。人们在理解植物如何对硼毒性做出反应方面取得了相当大的进展，并做出了相关努力来研究：（I）硼的吸收和在植物体内的分配，（II）硼过量引起的生理、生化和分子变化，特别强调对光合作用过程、硼引发的氧化应激以及抗氧化剂对硼毒性的反应的影响，最后（III）硼耐受机制。本文综述了最近关于硼毒性影响的研究结果，旨在阐明硼过量的影响，并提出新的观点，旨在推动该主题的未来研究。
