Defining phosphorus efficiency in plants

An experiment was conducted in a growth chamber to evaluate characteristics of the rhizosphere of maize genotypes contrasting in P-use efficiency, by determining length and density of root hairs, the rhizosphere pH and the functional diversity of rhizosphere bacteria. A sample of a Red Oxisol was limed and fertilized with N, K and micronutrients. In the treatment with the highest P level, 174 mg kg-1 P was added. Each experimental unit corresponded to a PVC rhizobox filled with 2.2 dm-3 soil. The experiment was completely randomized with three replications in a 5 x 2 factorial design, corresponding to five genotypes (H1, H2 and H3 = P-efficient hybrids, H4 and H5 = P-inefficient hybrids) and two P levels (low = 3 mg dm-3, high = 29 mg dm-3). It was found that 18 days after transplanting, the nodal roots of the hybrids H3 and H2 had the longest root hairs. In general, the pH in the rhizosphere of the different genotypes was higher than in non-rhizosphere soil, irrespective of the P level. The pH was higher in the rhizosphere of lateral than of nodal roots. At low P levels, the pH variation of the hybrids H2, H4 and H5 was greater in rhizospheric than in non-rhizospheric soil. The functional microbial activity in the rhizosphere of the hybrids H3 and H5 was highest. At low soil P levels, the indices of microbial functional diversity were also higher. The microbial metabolic profile in the rhizosphere of hybrids H1, H2, H3, and H5 remained unaltered when the plants were grown at low P. The variations in the rhizosphere properties could not be related to patterns of P-use efficiency in the tested genotypes.

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The phosphorus efficiency of three annual legumes

Plant and Soil ◽

10.1007/bf02107187 ◽

1978 ◽

Vol 50 (1-3) ◽

pp. 387-398 ◽

Cited By ~ 45

Author(s):

Graeme J. Blair ◽

Santos Cordero

Keyword(s):

Phosphorus Efficiency ◽

Annual Legumes

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Genetic Analysis of Agricultural Traits in Rice Related to Phosphorus Efficiency

Acta Genetica Sinica ◽

10.1016/s0379-4172(06)60093-0 ◽

2006 ◽

Vol 33 (7) ◽

pp. 634-641 ◽

Cited By ~ 3

Author(s):

Zai-Hua GUO ◽

Ping DING ◽

Li-Yuan HE ◽

Cai-Guo XU

Keyword(s):

Genetic Analysis ◽

Phosphorus Efficiency

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Genetic variability for root morph-architecture traits and root growth dynamics as related to phosphorus efficiency in soybean

Functional Plant Biology ◽

10.1071/fp09215 ◽

2010 ◽

Vol 37 (4) ◽

pp. 304 ◽

Cited By ~ 49

Author(s):

Junhua Ao ◽

Jiabing Fu ◽

Jiang Tian ◽

Xiaolong Yan ◽

Hong Liao

Keyword(s):

Genetic Variability ◽

Root Growth ◽

Recombinant Inbred Lines ◽

Growth Dynamics ◽

Root Traits ◽

Phosphorus Efficiency ◽

P Efficiency ◽

Glycine Max L ◽

Positive Correlations

Root morphology and architecture are believed to be important for plant phosphorus (P) efficiency, but their genetic information is relatively scarce. In the present study, a field and a specially designed minirhizotron experiments were conducted using two soybean (Glycine max L. Merr.) genotypes and their 88 recombinant inbred lines (RILs) to elucidate the genetic variability for root morph-architecture traits and root growth dynamics as related to P efficiency in soybean. The results indicated that the root morph-architecture traits were continually segregated in the RILs with a normal distribution, indicating which are possibly controlled by quantitative trait loci. Significantly positive correlations were found between root and P traits, suggesting feasibility of screening P efficient genotype through simple selection of root traits in field. Most root morph-architecture traits were closely correlated, showing a coordinating contribution to P efficiency. Furthermore, root morphological traits always had higher heritability than architecture traits, thus, could serve as more reliable index in field selection. The dynamic parameters of root growth from the minirhizotron experiment showed that the P efficient genotype established longer and larger root system with preferring distribution in surface layer and also kept more active roots, therefore, had a better growth performance in field, than the P-inefficient genotype. Taken together, this is the first report on in situ root growth dynamics and its relation to P efficiency using minirhizotron systems in crops. Our findings help to better understand the relationships between P efficiency and root traits and, thus, facilitate development of P efficient genotypes in crops.

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