Effect of Prohexadione Calcium on Growth Components and Endogenous Gibberellins Contents of Rice (Oryza sativa L.)

Abstract

Prohexadione calcium (Pro-Ca) is a novel plant growth regulator that inhibits the late stages of gibberellins (GAs) biosynthesis in plants, thus reducing the vegetative growth of the plant. Pro-Ca was applied to field-grown rice cultivar Ilpumbyeo to evaluate its effect on growth and yield components and endogenous GAs, when applied at different rates and timings. This study illustrated that Pro-Ca application decreased the internode length, stem length, panicle length, shoots fresh weight and stem lodging index, while stem breaking force was increased in all treatments. The effect of Pro-Ca was more pronounced in 20 ppm concentration than 10 ppm. The number of panicles m )2 , ripened grain ratio and 1000 grain weight and milled rice yield parameters, increased with the application of Pro-Ca, though the number of grains per panicle decreased insignificantly. The endogenous bioactive GA 1 contents significantly decreased with the application of Pro-Ca, as the GA biosynthesis was interrupted at later stages, when GA 20 conversion to GA 1 was blocked, thus drastically reducing GA 1 and GA 8 levels, but only insignificant changes were observed for intermediates from GA 12 to GA 20 . The levels of the endogenous GAs in rice shoots were measured by GC-MS-SIM using 2 H 2 -labelled GAs as internal standards. Present results also illustrated that early application of Pro-Ca was more effective than its late application for effective control of different growth parameters and thus reducing lodging in rice plants.

Effect of silicon on growth and salinity stress of soybean plant grown under hydroponic system

“…The metabolism of GA has been investigated and well understood (Sponsel and Hedden 2004). The active GAs are formed through two parallel pathways; the non C13-hydroxylation (leading to GA 4 ) and the early C13-hydroxylation (leading to GA 1 ) (Taiz and Zeiger 2002;Kim et al 2007;Fischbach and Clardy 2007). Both of these GAs biosynthesis pathways are found functional in soybean.…”

Prohexadione calcium on the growth and quality of eggplant seedlings

“…Prohexadione calcium has shown excellent vegetative growth-control properties in a number of plant species, such as rice, apple, petunia, and various vegetable crops, including cucumber and tomato (Ilias & Rajapakse, 2005;Ergun et al, 2007;Kim et al, 2007;Altintas, 2011). Soaking of faba bean seeds in solutions of prohexadione calcium caused significant reduction in shoot height and shoot fresh weight, with increasing prohexadione calcium concentrations (Bekheta et al, 2009).…”

Redução da poda hibernal e aumento da produção de pereiras 'Hosui' pelo uso de prohexadiona cálcio

“…Giberelinas ativas como a GA 1 desempenham um papel importante no alongamento de ramos de pomáceas, cujo precursor imediato é a GA 20 , biologicamente inativa. A prohexadiona cálcio regula os estágios finais da biossíntese de giberelinas (Ilias & Rajapakse, 2005;Kim et al, 2007), pois bloqueia a conversão do GA 20 para GA 1, de maneira a reduzir os níveis de giberelinas biologicamente ativas. De acordo com Rademacher et al (2006), a translocação de forma acrópeta no xilema traz como benefício o controle efetivo do desenvolvimento vegetativo em distintas partes da planta, além de apresentar rápido catabolismo metabólico, baixa toxicidade e persistência limitada.…”