Physiological responses of plants to low boron

Dell, Bernie and Huang, Longbin (1997) Physiological responses of plants to low boron. Plant and Soil, 193 1-2: 103-120. doi:10.1023/A:1004264009230

Author Dell, Bernie
Huang, Longbin
Title Physiological responses of plants to low boron
Journal name Plant and Soil   Check publisher's open access policy
ISSN 0032-079X
Publication date 1997-06
Sub-type Article (original research)
DOI 10.1023/A:1004264009230
Volume 193
Issue 1-2
Start page 103
End page 120
Total pages 18
Place of publication The Netherlands
Publisher Springer
Language eng
Subject 060705 Plant Physiology
Abstract This review focuses on physiological responses in higher plants to B deficiency at the whole plant and organ level. Plants respond to decreasing B supply in soil solutions by slowing down or ceasing growth. Boron deficiency inhibits root elongation through limiting cell enlargement and cell division in the growing zone of root tips. In the case of severe B deficiency, the root cap, quiescent centre and protoderm of root tips disappear and root growth ceases, leading to the death of root tips. Although vascular bundles are weakly developed in B-deficient roots, early effects of B deficiency on their initiation and differentiation is poorly understood. Inhibited leaf expansion by low B indirectly decreases the photosynthetic capacity of plants, though exact roles of B in photosynthesis remain to be explored. The early inhibition of root growth, compared to shoot growth, increases the shoot:root ratio. It is hypothesised that this may enhance the susceptibility of plants to environmental stresses such as marginally deficient supplies of other nutrients and water deficit in soil. In the field, sexual reproduction is often more sensitive to low soil B than vegetative growth, and marked seed yield reductions can occur without symptoms being expressed during prior vegetative growth. In flowers, low B reduces male fertility primarily by impairing microsporogenesis and pollen tube growth. Post-fertilisation effects include impaired embryogenesis, resulting in seed abortion or the formation of incomplete or damaged embryos, and malformed fruit. However, there is a great diversity of effects of low B on reproductive growth among species, and within the same species between sites and seasons. Much of this diversity is not explained by the current literature. Key processes in reproductive development which may be impaired under B deficiency are proposed and discussed. These include the formation of a diverse array of cell wall types, the supply of carbohydrates for growth and storage reserves, and the production of flavonols. Inflorescence architecture, floral morphology, canopy structure and prevailing weather conditions are suggested as being important for xylem B delivery into flowers because of their impact on transpiration. The extent of phloem translocation of B into reproductive organs has yet to be fully assessed. The timing of B sensitive stages in reproduction of most crop plants need defining in order to facilitate appropriate timing of corrective B treatments. As most container studies have imposed B deficiency by withholding B, much of the data on severely B-deficient plants requires re-evaluation. Further studies are warranted to understand the effects of realistically low levels of B in solution on the growth of meristematic tissues and floral organs. A B-buffered solution culture system is recommended for some of this work.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Centre for Mined Land Rehabilitation Publications
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Created: Wed, 21 Jul 2010, 14:08:02 EST by Laura McTaggart on behalf of Centre For Mined Land Rehabilitation