Contrasting Responses to Phosphorus Status by Arachis pintoi (Krapov and W.C. Gregory): A Lesson for Selecting Vegetables for Cultivation in Kenyan Ecozones

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dc.contributor.authorOnyango, Gweyi
dc.contributor.authorTesfamariam, T.
dc.contributor.authorNeumann, G.
dc.date.accessioned2014-10-16T09:01:26Z
dc.date.available2014-10-16T09:01:26Z
dc.date.issued2011
dc.description.abstractTropical soils are characterized by low pH with high aluminium saturation and phosphorus (p) fixation. Pinto Peanut (Arachis pintoi (Krapov and W.C. Gregory)) grows in such soils with no P deficiency symptoms. The current experiment dissected an array of mechanisms envisaged to explain growth advantages of Arachis pintoi (AP) in such P-deficient environments. Split root experiment was conducted with three ecotypes (CIAT 17434, CIAT 18744 and CIAT 22172) cultured in hydroponics with Hoagland solutions and P was later withheld from one root compartment. Nutrient solution pH was determined from 20-49 Days after sowing using pH meter, while exudates were collected by overlaying filter papers on root surfaces. Carboxylates were extracted from filter papers and later determined by HPLC (Bio-Rad, Richmond, CA, USA). CIAT 18744 produced significantly higher (p≤0.05) shoot and root (biomass), whereas CIAT 22172 had lowest. CIAT 18744 registered minimal acidification under P-deficiency compared to other two ecotypes and produced highest TCA cycle carboxylates (1.72 and 2.2 nmol/h/cm root length) malate and citrate, respectively whereas CIAT 22172, exuded only 0.50 and 0.52 nmol/h/cm root length] malate and citrate, respectively. There was no correlation between growth medium acidification and carboxylate exudation; probably implying carboxylates lacked contribution to growth medium acidification. Selecting for carboxylate exudation and internal P reallocation would be a better strategy in acid soils (e.g., Kenyan Alfisols) since carboxylates can complex aluminium without acidification of rhizosphere, while protonation that leads to rhizosphere acidification would be a better strategy in high pH soils, favoring availability of precipitated P (e.g., Calcareous Kenyan soils).en_US
dc.description.sponsorshipDAADen_US
dc.identifier.citationAsian Journal of Agricultural Research, 2011en_US
dc.identifier.issn1819-1894
dc.identifier.urihttp://docsdrive.com/pdfs/knowledgia/ajar/2011/45-55.pdf
dc.identifier.urihttp://ir-library.ku.ac.ke/handle/123456789/11471
dc.language.isoenen_US
dc.publisherKnowledgia Scientificen_US
dc.subjectpinto peanut(Arachis pintoi( Krapov and W.C. Gregory)en_US
dc.subjectp-deficiencyen_US
dc.subjectcarboxylate exudationen_US
dc.subjectrhizosphere pHen_US
dc.titleContrasting Responses to Phosphorus Status by Arachis pintoi (Krapov and W.C. Gregory): A Lesson for Selecting Vegetables for Cultivation in Kenyan Ecozonesen_US
dc.typeArticleen_US
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