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United States Department of Agriculture

Agricultural Research Service

Title: Soil and plant minerals associated with rice straighthead disorder induced by arsenic

Authors
item Yan, Wengui
item Agrama, Hesham - UNIV. OF AR RREC
item Slaton, Nathan - UNIV. OF AR FAYETTEVILLE
item Gibbons, James - UNIV. OF AR RREC

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 7, 2008
Publication Date: September 30, 2008
Citation: Yan, W., Agrama, H.A., Slaton, N.A., Gibbons, J.W. 2008. Soil and plant minerals associated with rice straighthead disorder induced by arsenic. Agronomy Journal. 100:1655-1661.

Interpretive Summary: Straighthead is a physiological disorder resulting in abnormal development of panicles and sterility in rice. Application of arsenic (As) as monosodium methanearsonate (MSMA) to soil has become the common practice for evaluation of rice straighthead. So far, no study has reported on soil mineral availability and plant mineral uptake as affected by the MSMA straighthead evaluation. Understanding how MSMA influences nutrient availability and uptake should help reveal the causal factors of rice straighthead. Six cultivars rated as resistant (3), susceptible (2) and moderately susceptible (1) to straighthead were studied with four replications in soils receiving 0 and 6.7 kg MSMA ha-1 in 2004 and 2005. Fourteen soil minerals or parameters including pH, EC, P, K, Ca, Mg, S, Na, Fe, Mn, Zn, Cu, As and LOI were studied. Twelve minerals including P, K, Ca, Mg, S, Na, Fe, Mn, Zn, Cu, B and As in both flag leaf and heading panicles, and their association with days to 50% heading, plant height, straighthead symptoms and grain yield were analyzed.

Technical Abstract: Application of arsenic (As) as monosodium methanearsonate (MSMA) to soil has become the common practice for evaluation of rice straighthead, a physiological disorder. So far, no study has reported on soil mineral availability and plant mineral uptake as affected by the MSMA straighthead evaluation. Understanding how MSMA influences nutrient availability and uptake should help reveal the causal factors of rice straighthead. Six cultivars rated as resistant (3), susceptible (2) and moderately susceptible (1) to straighthead were studied in soils receiving 0 and 6.7 kg MSMA ha-1 in 2004 and 2005. Soil, flag leaves and heading panicles were sampled and analyzed. Straighthead induced by MSMA was so severe that the susceptible cultivars yielded no grain, which indicated effective induction of straighthead. MSMA incorporation decreased soil pH, P, Mg and Ca, increased As, S and Mn, but had no influence on soil EC, Na, K, Zn, Cu, Fe and organic matter. Decreased soil pH resulted from the MSMA was associated with less Ca, Mg and P but more S, Mn and As in the soil. MSMA increased As, Cu, Mn, Fe, S and K but decreased B concentrations in the flag leaves, and increased As, Mn, S, K and P but decreased Zn and Ca concentrations in the panicles. Severe straighthead dramatically reduced grain yield and was associated with decreased Ca, Mn and S, but not with As in flag leaves. Comparisons between naturally occurring straighthead reported in literature and artificially induced straighthead from this study indicate plant and soil nutrients may behave differently when MSMA is applied. Straighthead is a complex disorder which requires further research to enhance our understanding of its casual factors.

Last Modified: 8/29/2014
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