Hormones in the grains and roots in relation to post-anthesis development of inferior and superior spikelets in japonica/indica hybrid rice

• Published in: Plant physiology and biochemistry Vol. 47; no. 3; pp. 195 - 204
• Main Authors: Zhang, Hao, Tan, Guilu, Yang, Linian, Yang, Jianchang, Zhang, Jianhua, Zhao, Buhong
• Format: Journal Article
• Language: English
• Published: Paris Elsevier Masson SAS 01.03.2009; Elsevier
• Subjects: Abscisic acid; Biological and medical sciences; Cell Division; Endosperm cell; Fundamental and applied biological sciences. Psychology; Gibberellins; Grain filling; Hybridization, Genetic; Indole-3-acetic acid; Japonica/indica hybrid rice ( Oryza sativa); Oryza - cytology; Oryza - growth & development; Oryza - physiology; Plant Growth Regulators - metabolism; Plant Growth Regulators - physiology; Plant physiology and development; Plant Roots - metabolism; Seeds - metabolism; Zeatin + zeatin riboside; Japonica/indica hybrid rice ( Oryza sativa); ABA; I/I; Indole-3-acetic acid; Gibberellins; J/I; IAA; Grain filling; Endosperm cell; FW; DPA; Zeatin + zeatin riboside; Abscisic acid; GAs; ZR; Z; ELISA; Hybrid variety; Monocotyledones; Auxin; Cereal crop; Oryza sativa; Gramineae; Indoleacetic acid; Sesquiterpenes; Angiospermae; Development; Plant growth substance; Endosperm; Cell; Adenine derivatives; Hormone; Spikelets; Grains; Japonica/indica hybrid rice (Oryza sativa); Gibberellin; Cytokinin; Plant physiology; Post-anthesis; Spermatophyta; Ribonucleoside; Fructification
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2008.11.012

Grain filling is usually not adequate in later-flowering inferior spikelets in japonica/indica (J/I) hybrid rice ( Oryza sativa) although it shows stronger hybrid vigor than indica/indica (I/I) hybrid. This study investigated the potential causes by examining changes in zeatin (Z) + zeatin riboside (ZR), indole-3-acetic acid (IAA), gibberellins (GAs, GA 1 + GA 4), and abscisic acid (ABA) in spikelets and roots during the grain filling period. The inferior spikelets of J/I hybrid exhibited low rate of endosperm cell division and slow grain filling. During the early grain filing period, they had less Z + ZR, IAA, and ABA, but more GAs, than the earlier-flowering superior spikelets. If compared to the inferior spikelets of the I/I hybrid, the J/I inferior spikelets also had less Z + ZR, IAA, and ABA. Rates of endosperm cell division and grain filling were positively and significantly correlated with Z + ZR and ABA contents in both grains and roots or IAA in grains, whereas not significantly correlated with GAs either in grains or roots or IAA in roots. Applications of kinetin, IAA, or ABA to spikelets, or kinetin and ABA to roots, enhanced cell division and grain filling in the inferior spikelets. Results suggest that low contents of cytokinins and ABA in both grains and roots and low contents of IAA in grains may result in the poor filling of inferior spikelets in the J/I hybrid.