Functional manganese requirement and its use as a critical value for diagnosis of manganese deficiency in subterranean clover (Trifolium subterraneum L. cv. Seaton park)
Nable, R.O., Bar-akiva, A. and Loneragan, J.F. (1984) Functional manganese requirement and its use as a critical value for diagnosis of manganese deficiency in subterranean clover (Trifolium subterraneum L. cv. Seaton park). Annals of Botany, 54 (1). pp. 39-49.
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The effects of manganese supply on plant growth and on photosynthesis and manganese concentrations in young leaves were examined in Seaton Park subterranean clover in three glasshouse water culture experiments.Plants werc grown initially with a copious supply of manganese, and transferred to solutions either with or without manganese. Sequential harvests were taken to determine the effects of developing manganese deficiency on dry matter (DM) yield of whole plants and selected characteristics [manganese, chlorophyll and photosynthetic oxygen evolution (POE)] of youngest open leaf blades (YOL). In addition, the deffect of leaf age and iron supply on POE werc examined.Manganese concentrations and POE in YOL declined markedly and rapidly in plants transferred to solutions without manganese, while chlorophyll concentrations of YOL and plant DM yield responded more weakly and more slowly. As a result, a level of manganese deficiency which depressed POE in young leaves by more than 50 per cent had no effed on DM production.In youngleaves (YOL, YOL + 1, YOL-1), POE declined when their manganese concentrations were < 20 μg g -1 DM. Iron supply did not affect this rdationship. When learn with < 20 μg Mn g -1 DM were detached and incubated for 24 h in solutions containing high concentrations of manganese, their POE increased to normal rates; leaves with higher manganese concentrations did not respond. It is suggested that the value of 20 μg Mn g -1 DM is the functional manganese requirement for POE in young subterranean clover leaves It is also suggested that this value may be used as a critical value for indicating manganese deficiency in subterranean clover.Functional nutrient requirements determined in this way by correlation of nutrient concentrations in young leaves with their biochemical or physiological activities appear to offer more accurate and consistent standards for use an critical values for diagnosis of plant nutrient status than do the critical values determined in the usual way by correlation with plant dry weight.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Environmental and Life Sciences|
|Publisher:||Oxford University Press|
|Copyright:||© 1984 Annals of Botany Company.|
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