Sakarya Üniversitesi Fen Bilimleri Enstitüsü Dergisi (Dec 2016)
A study on drought stress tolerance in some maize (Zea mays L.) cultivars
Abstract
In this study, some morphological and physiological parameters of three maize (Zea mays L.) cultivars, cv. FR13, FRB73 and TTM815, were analysed to investigate their tolerance to drought stress. Twenty-one-day old plants were subjected to three different regime of drought stress by withholding Hoagland’s nutrient solution for 2 (mild drought stress), 5 (moderate drought stress), and 8 (severe drought stress) days. Root growth in cultivars FR13 and TTM815 was significantly inhibited by moderate and severe drought stress while shoot growth in all maize cultivars was not affected under all drought treatments. Our results showed that inhibited root growth under mild and severe drought conditions was responsible for decreased total plant lenght in all cultivars although FRB73 was less affected. Fresh and dry biomass increased in all cultivars under all drought treatments, however it was more significant in FRB73. These results may indicate that water relations in FRB73 can be regulated more properly under drought stress, as indicated by relatively constant water content. “Chlorophyll a” content in FR13 and TTM815 was decreased at the end of the treatments while it was not affected in FRB73 by drought stress. “Chlorophyll b” content in FR13 and FRB73, on the other hand, was less affected by drought treatments. Malondialdehyde accumulation in all cultivars increased considerably as a result of all drought treatments, however to a less extent in FRB73. Total phenolic contents in all cultivars were increased especially by moderate and severe drought stress. Total soluble sugar contents in FR13 and TTM815 were decreased significantly by mild and severe drought stress while it remained constant in FRB73 under all drought treatments. According to our results, it may be concluded that FRB73 is more drought tolerant maize cultivar because of the ability of maintaining root and shoot growth, accumulation of phenolics, fresh and dry biomass, relatively less affected water, photosynthetic pigment (chlorophyll a and b) and sugar content and lower level of malondialdehyde under drought stress when compared to FR13 and TTM815.
Keywords
