Root traits as tools for creating phosphorus efficient crop varieties

被引:38
作者
Tara Singh Gahoonia
Niels Erik Nielsen
机构
[1] The Royal Veterinary and Agricultural University,Department of Agricultural Sciences, Plant Nutrition and Soil Fertility Laboratory
来源
Plant and Soil | 2004年 / 260卷
关键词
breeding; mycorrhiza; organic acids; phosphatase; root hairs; root morphology;
D O I
暂无
中图分类号
学科分类号
摘要
This paper provides a brief assessment of the genetic variation in root properties (root morphology, including root hairs), mycorrhizal symbiosis, uptake kinetics parameters and root-induced changes (pH, organic acids and acid phosphatase) in the rhizosphere of various crop species and their genotypes and then briefly discusses the opportunities and challenges of using such knowledge for enhancing P efficiency of future crop genotypes by genetic means. Wide genotypic variation and heritability of root morphology, root hair length and density and thereby P acquisition provide opportunities for selection and breeding for root characteristics for increasing P acquisition. The progress is challenged by the concerns of high carbon cost of larger root systems and by the lack of cost effective methods to determine root length of a large number of genotypes under field conditions. The carbon cost of root hairs is low. Furthermore, low cost methods now exist to compare root hair formation of field grown genotypes. The development and application of sophisticated methods has advanced our knowledge on the role of mycorrhizal symbiosis in P acquisition and also on the molecular basis of fungi and plant interactions. However, extensive studies to explore genotypic variation in mycorrhizal responsiveness are rare, which makes it difficult to assess, how mycorrhizal symbiosis can be manipulated through breeding efforts. The promising variation found in P uptake kinetics parameters of crop genotypes in few studies indicates that more genotypes may be screened by relatively simple nutrient solution culture techniques. The genetic manipulation of the overall differences in cation-anion uptake, which is the main cause of rhizosphere pH change, may be difficult. For manipulation of rhizosphere pH, agronomic measures such as applications of ammonium or nitrate fertilisers may be more useful than breeding approaches. Also it seems difficult to assess what kind of genetic analysis should be performed to support the breeding efforts. Phosphorus mobilisation effect of pH depends on soil P compounds, therefore will differ with soil type. Both the enhanced release of organic acids and higher acid phosphatase activity in the rhizosphere may be useful for increasing P acquisition from inorganic and organic P pools, respectively. Modification of these traits by genetic means should be considered. For successful breeding programmes, the role of various root traits needs to be targeted in an integrated manner and then methods need to be developed for studying their importance under natural soil conditions, so that the genotypic variation can be explored and their ecological significance in P acquisition can be established.
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页码:47 / 57
页数:10
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  • [81] Knight J. D.(1998). Identification of root hair specific proteins by Planta 206 544-397
  • [82] Vance CP(2002) labelling Philos. Trans. Royal Soc. London series B-Biol. Sci. 357 449-215
  • [83] Allan DL(2001)Function and mechanism of organic anion exudation from plant roots Plant Physiol. 127 390-632
  • [84] Graham JH(1990)Land use transformation in Africa: Three determinants for balancing food security with natural resources utilization Euphytica 46 211-1093
  • [85] Eissenstat DM(1997)Genetic control of root hair development in Theor. Appl. Genet. 94 619-255
  • [86] Grierson C. S.(1995)Nitrate and ammonium absorption by plants growing at a sufficient or insufficient level of phosphorus in nutrient solution Crop Sci. 35 1086-undefined
  • [87] Parker JS(2001)Response of inbred lines and crosses in maize to vari-ation of nitrogen and phosphorus supplies as nutrients Plant Soil 237 249-undefined
  • [88] Kemp AC(undefined)Rhizodeposition and turnover of root-derived or-ganic material in barley and wheat under conventional and integrated management undefined undefined undefined-undefined
  • [89] Grinsted M. J.(undefined)Phosphatase activity in the rhizo-sphere and its relation to the depletion of organic phosphorus undefined undefined undefined-undefined
  • [90] Hedley M. J.(undefined)Agricultural sustainability and intensive production practices undefined undefined undefined-undefined