Open AccessThe responses of root morphology and phosphorus-mobilizing exudations in wheat to increasing shoot phosphorus concentration
Author(s) -
Qi Shen,
Zhihui Wen,
Yan Dong,
Haigang Li,
Yuxin Miao,
Jianbo Shen
Publication year - 2018
Publication title -
aob plants
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.998
H-Index - 39
ISSN - 2041-2851
DOI - 10.1093/aobpla/ply054
Subject(s) - shoot , rhizosphere , phosphorus , dry weight , biology , agronomy , horticulture , phosphorus deficiency , biomass (ecology) , nutrient , zoology , botany , chemistry , ecology , genetics , organic chemistry , bacteria
The adaptations of root growth and rhizosphere processes for soil phosphorus (P) acquisition have been investigated intensively in wheat ( Triticum aestivum ). However, only a few studies paid attention to these responses to shoot P status. This study aimed at investigating the responses of root morphology and P-mobilizing exudation to increasing shoot P concentration. A broad range of wheat shoot P concentrations (1.0–7.1 mg per g dry weight) was set up with 11 rates of P supply: 0–1200 mg P per kg soil. Root morphology and exudation parameters were measured after 37 days of plant growth. Shoot dry biomass reached a maximum when shoot P concentration was 4.63 mg per g dry weight. The maximum shoot P concentration for total root length, specific root length and the proportion of fine root (diameter ≤ 0.2 mm) length to total root length was 3 mg per g dry weight. Rhizosphere acidification was positively correlated with shoot P concentration when this was <5 mg per g dry weight. Shoot P concentration did not change acid phosphatase activity in the rhizosphere. Citrate concentration in the rhizosphere was suppressed by increasing shoot P concentration. In contrast, malate concentration in the rhizosphere showed a positive correlation with shoot P concentration. In conclusion, wheat root morphological and P-mobilizing exudation traits showed different behaviours with increasing P deficiency stress. Maintaining root biomass and length is the major strategy rather than root exudation for wheat to cope with extreme P deficiency.