Straighthead disease of rice ( Oryza sativa L.) induced by arsenic toxicity

• Published in: Environmental and experimental botany 2008, Vol.62 (1), p.54-59
• Main Authors: Rahman, M. Azizur, Hasegawa, H., Rahman, M.M., Miah, M.A.M., Tasmin, A.
• Format: Article
• Language: English
• Subjects: application rate; Arsenic; Biological and medical sciences; BRRI dhan 29; disease incidence; disease severity; Fundamental and applied biological sciences. Psychology; grain yield; height; inflorescences; length; Oryza sativa; Physiological diseases. Varia; Phytopathology. Animal pests. Plant and forest protection; phytotoxicity; plant diseases and disorders; plant fertility; rice; Rice ( Oryza sativa L.); soil pollution; Spikelet; Straighthead disease; tillering; Toxicity
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2007.07.016

Straighthead disease is a physiological disorder of rice ( Oryza sativa L.) characterized by sterility of the florates/spikelets leading to reduced grain yield. Though the exact cause of straighthead is unknown, a glass house experiment was conducted to investigate the effect of inorganic arsenic on straighthead disease in rice ( Oryza sativa L.). BRRI dhan 29, a popular Bangladeshi rice strain, was grown in soils spiked with arsenic (prepared from sodium arsenate, Na 2HAsO 4·7H 2O) at the rate of 10, 20, 30, 40, 50, 60, 70, 80 and 90 mg of As kg −1 and one control treatment was also run to compare the results. Although there may be some other soil physico-chemical factors involved, arsenic concentration was found to be closely associated with straighthead of rice. With the increase of soil arsenic concentration, the severity of straighthead increased significantly. Up to the 50 mg of As kg −1 soil treatments, the severity of straighthead incidences were not prevalent. Straighthead resulted in sterile florets with distorted lemma and palea, reduced plant height, tillering, panicle length and grain yield. Straighthead caused approximately 17–100% sterile florates/spikelets formation and about 16–100% loss of grain yield. Straighthead also causes the reduction of panicle formation and panicle length significantly ( p < 0.01). In the present study, panicle formation was found to be reduced by 21–95% by straighthead.