Full text
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| Author(s): |
Luiz Tadeu Jordão
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Centro de Energia Nuclear na Agricultura (CENA/STB) |
| Defense date: | 2014-02-21 |
| Examining board members: |
José Lavres Junior;
Adilson de Oliveira Junior
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| Advisor: | José Lavres Junior |
| Abstract | |
Studies on the potassium use efficiency (KUE), potassium uptake efficiency (KUpE) as well as the definition of critical values of K in soil and plant for soybean cultivars with determinate growth type (DGT) and indeterminate (IGT) are fundamental to the selection of genotypes to nutritional requirements and allow placement of these materials for cultivation in different edaphic environments. This study aimed to evaluate the K (and Rubidium - Rb) uptake efficiency by uptake kinetics (Vmax, Km and Cmín) assessment and root morphology, the K use efficiency (KUE) through the transport and redistribution of K (and Rb) in plant parts, and define critical values of K in the soil and leaves used for diagnosis for soybeans with IGT. The first two experiments (uptake kinetics of Rb and root morphology, transport and redistribution of K/Rb) were carried out in greenhouse conditions at CENA/USP, from October 2012 to January 2013, and the third experiment was developed under field conditions at Embrapa Soybean, from September 2010 to March 2013. For the first two experiments, one cultivar with DGT (TMG 1066 RR) and three with IGT (VMAX RR, NA RG 5909 and BRS 360 RR) was used, and for the last experiment was used the soybean cultivars with IGT VMAX RR and BRS 360 RR. There was genotypic variation in morphologic parameters of the roots, except for the root diameter. The uptake kinetics parameters Vmax, Km and Cmín ranged among the cultivars on each concentration of Rb. However, no difference was observed on the K uptake efficiency (KUpE) among the cultivars from DGT or IGT group. There was a significant interaction between genotypes and treatments of Rb for the variables grain mass yield, putrescine, K and Rb accumulation, Rb redistribution, long distance transport of K and K use efficiency (KUE). The TMG 1066 RR and VMAX RR cultivars have a greater efficiency in production and use of K. No differences were found concerning the accumulation and redistribution of K for DGT and IGT cultivars. Symptoms of K deficiency were found in two soybean cultivars from the beginning of pod formation and grain filling. The soil critical levels of K to VMAX RR and BRS 360 RR genotypes were 0.38 and 0.29 cmolc dm-3, respectively, while the plant-tissue critical levels of K for the same cultivars were 25.4 and 21.3 g kg-1, respectively. The soil and plant-tissue critical level values obtained in this study are higher than those in the literature for genotypes with determinate growth type (DGT) (AU) | |
| FAPESP's process: | 12/13686-5 - Potassium (85rubidium) uptake, translocation and its efficiency use in indeterminate growth type soybean cultivars |
| Grantee: | Luiz Tadeu Jordão |
| Support Opportunities: | Scholarships in Brazil - Master |