TY - JOUR
T1 - Soil phosphorus availability determines the preference for direct or mycorrhizal phosphorus uptake pathway in maize
AU - Zhang, Lin
AU - Chu, Qun
AU - Zhou, Jianwei
AU - Rengel, Zed
AU - Feng, Gu
PY - 2021/12/1
Y1 - 2021/12/1
N2 - How plants balance different strategies to acquire resources from the environment is a basic question in biology and ecology. Phosphorus (P) uptake by mycorrhizal plants comprises direct pathway (DP) and mycorrhizal pathway (MP). It is unknown whether there is a trade-off between DP and MP and how plants govern selection and/or differential contributions of the two pathways. We used 32P labelling technique to quantify P uptake by both pathways in three maize genotypes differing in P acquisition at Olsen P values of 4.5, 8 and 50 mg kg−1, representing low, suboptimal and high P supplies, respectively. We calculated the preference index of P uptake (ratio of MP contribution to DP contribution), P-transporter-based preferential index, C investment index as (ratio of hyphal length to root length), and the P-efficiency-based preferential index. Our results showed that maize plants preferred MP at the suboptimal soil available P because both the C investment index and the P-efficiency-based preferential index were greatest at that P supply. Shoot P content showed a significant relationship with the P uptake preference index, suggesting shoot P demand governed the trade-off between DP and MP. In conclusion, the preference for DP or MP regarding P acquisition in maize shifts with changes in soil available P level. These findings could be harnessed to better manage mycorrhizal fungi to enhance the sustainability of agricultural crops in soils with suboptimal P availability.
AB - How plants balance different strategies to acquire resources from the environment is a basic question in biology and ecology. Phosphorus (P) uptake by mycorrhizal plants comprises direct pathway (DP) and mycorrhizal pathway (MP). It is unknown whether there is a trade-off between DP and MP and how plants govern selection and/or differential contributions of the two pathways. We used 32P labelling technique to quantify P uptake by both pathways in three maize genotypes differing in P acquisition at Olsen P values of 4.5, 8 and 50 mg kg−1, representing low, suboptimal and high P supplies, respectively. We calculated the preference index of P uptake (ratio of MP contribution to DP contribution), P-transporter-based preferential index, C investment index as (ratio of hyphal length to root length), and the P-efficiency-based preferential index. Our results showed that maize plants preferred MP at the suboptimal soil available P because both the C investment index and the P-efficiency-based preferential index were greatest at that P supply. Shoot P content showed a significant relationship with the P uptake preference index, suggesting shoot P demand governed the trade-off between DP and MP. In conclusion, the preference for DP or MP regarding P acquisition in maize shifts with changes in soil available P level. These findings could be harnessed to better manage mycorrhizal fungi to enhance the sustainability of agricultural crops in soils with suboptimal P availability.
KW - Direct P uptake
KW - Maize
KW - Mycorrhizal P uptake
KW - Preferential P uptake pathway
KW - Trade-off
UR - http://www.scopus.com/inward/record.url?scp=85107701334&partnerID=8YFLogxK
U2 - 10.1016/j.geoderma.2021.115261
DO - 10.1016/j.geoderma.2021.115261
M3 - Article
AN - SCOPUS:85107701334
SN - 0016-7061
VL - 403
JO - Geoderma
JF - Geoderma
M1 - 115261
ER -