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Landrace of japonica rice, Akamai exhibits enhanced root growth and efficient leaf phosphorus remobilization in response to limited phosphorus availability

Author:
Dissanayaka, D. M. S. B., Maruyama, Hayato, Nishida, Sho, Tawaraya, Keitaro, Wasaki, Jun
Source:
Plant and soil 2017 v.414 no.1-2 pp. 327-338
ISSN:
0032-079X
Subject:
cultivars, inflorescences, inorganic phosphorus, plant organs, rice, landraces, developmental stages, shoots, acclimation, soil, grain yield, root growth, roots, leaves, crops
Abstract:
AIMS: Phosphorus (P) acquisition through extensive root growth and P allocation to different plant organs through efficient remobilization are important for acclimation of crop plants to P-limited environments. This study elucidated changes in rice root growth and leaf P-remobilization and their influence on grain yield under P deficiency. METHODS: Two pot experiments were conducted with (P100) and without (P0) inorganic P supply using two Japanese rice cultivars: Akamai (Yamagata) and Koshihikari. Multiple harvests were made until the panicle initiation stage. Root and shoot growth response, P acquisition, and temporal leaf P-remobilization efficiency were measured. A separate experiment ascertained the final yield and grain P status. RESULTS: The Akamai rice cultivar showed enhanced root growth and more acquired soil P. The Akamai root dry weight was 66% greater than that of Koshihikari under P0. Confronting P deficiency, Akamai remobilized some P from its lower mature leaves to upper younger leaves starting from early growth. The remobilized P fraction increased to 72% at panicle initiation under P0. Under P0, Akamai exhibited two-fold higher leaf P-remobilization efficiency than under P100. CONCLUSIONS: Enhanced root growth that facilitates acquisition of more soil P through better soil exploration coupled with efficient leaf P remobilization from the early growth stage improves adaptation of Akamai rice cultivar to P-limited environments. Nevertheless, P-starvation responses did not facilitate higher grain yields in P-limited conditions.
Agid:
5725780