Objectives The availability of soil P has a significant influence on the traits of above- and below-ground parts of plants. We studied the changes of shoot and root traits of wheat (Triticum aestivum L.) under high and low P supply conditions, to clarify their correlations.
Methods A pot experiment was carried out in the greenhouse of Hebei Agricultural University. The test soil available P was 5.50 mg/kg, and P application rate of 0 and 200 mg/kg were set up to simulate low and high P supply conditions (LP, HP). 10 wheat varieties, with P efficiency of mid value about 0.12, were selected as test plant materials. Wheat plants were grown for 35 days and harvested for the determination of five above-ground traits (shoot dry weight, relative growth rate, shoot P uptake, shoot P content and SPAD) and nine below-ground traits (root dry weight, root length, root/shoot ratio, specific root length, root diameter, proportion of fine root length, root tissue density, rhizosphere soil pH and acid phosphatase activity).
Results Compared with HP, LP treatment significantly reduced shoot dry weight, P uptake and P content of wheat shoot by 57.9%–72.2%, 85.7%–89.8%, 61.3%–71.7%; significantly increased root length, proportion of fine root length, root tissue density, root shoot ratio and specific root length by 50.9%–249.5%, 32.5%–442.5%, –34.5%–400.0%, 27.4%–198.9%, 74.4%–395.3%; significantly increased acid phosphatase activity by –8.1%–120.9%. There were 32 pairs of traits significantly correlated between above- and below-ground part of wheat under LP condition, and only 20 pairs significantly correlated under high P condition. The correlation between above- and below-ground traits of wheat under low P condition was 60% higher than that under HP.
Conclusions The correlations between the shoot and root traits of wheat are relatively high under low P condition, but high P supply reduced these correlations between above- and below-ground traits.
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