Influence of Water Stress on Endogenous Hormone Contents and Cell Damage of Maize Seedlings

Abstract

Phytohormones play critical roles in regulating plant responses to stress. We investigated the effects of water stress induced by adding 12% (w/v) polyethylene glycol to the root medium on the levels of abscisic acid (ABA), indole-3-acid (IAA), zeatin (ZT), and gibberellin(3) (GA(3)) in maize leaves. The results suggested that water stress had significant effects on the four hormone levels. There was a transient increase in the IAA content during the initial stage of adaptation to water stress in maize leaves, but it dropped sharply thereafter in response to water stress. ABA content increased dramatically in maize leaves after 24 h of exposure to water stress, and then the high levels of ABA were maintained to the end. The contents of ZT and GA(3) rapidly declined in maize leaves subjected to water stress. The effects of water stress on chlorophyll content, electrolyte leakage and malondialdehyde levels in maize leaves were also studied. The variation of cell damage was negatively correlated with ZT and GA(3) levels in maize leaves under water stress. Thus, we explored the roles of ZT and GA(3) on the growth of maize seedlings under water stress by exogenous application. It is possible that both ZT and GA(3) were effective in protecting maize seedlings from water stress, which would be of great importance for the improvement of drought tolerance in maize by genetic manipulation.

Determination of Endogenous Hormones Content in Cotton Varieties (Gossypiumhirsutum) as Influenced by Phosphorus and Potassium Nutrition

“…The exogenous hormones applied during the second experiment altered growth and development of cotton plants. This result was similar toTao et al (1993) on pea seedling growth, Zahir et al (2001) on growth and yield of rice, Gialvalis, and Seagull, (2001) on plant hormones altered fiber initiation in unfertilized cultured ovules of Gossypiumhirsutum, Chunrong et al (2008) on endogenous and exogenous hormones of water stress in maize seedling.…”

ARABIDOPSIS THALIANA HOMEOBOX25 Uncovers a Role for Gibberellins in Seed Longevity

“…GA 3 -treated plants and the quintuple DELLA mutant, which shows constitutive activation of the GA signaling pathway, produced seeds that are more resistant to accelerated aging, as compared with their respective controls. However, plants subjected to drought stress, with an expected decrease in GA content (Wang et al, 2008), and the pre1 mutant, with a compromised Figure 6. ATHB25 increases GA levels and the expression of GA3OX2.…”

Drought Tolerance and Stress Hormones: From Model Organisms to Forage Crops

“…In addition to the well established model of Arabidopsis, increments in endogenous ABA level under water stress are also reported in cereals and forage crops. For instance, increment in ABA contents under water stress in diverse developmental stages was reported in maize (Xin et al, 1997;Wang et al, 2008;Nyysar 2005), sorghum (Kannangara et al, 1983), wheat (Iqbal et al, 2010;Raziuddin et al, 2010), festuca (Abernethy and McManus 1998), barley (Thameur et al, 2010) and alfalfa (Han et al, 2008). Plants of wheat and maize, representatives of C3 and C4 plants, respectively, were subjected to mild (−0.4MPa), moderate (−0.8MPa) and high (−1.5MPa) water stress levels induced by PEG-6000 for 7 days under controlled conditions.…”

“…Higher ABA content in maize may also impose greater stomatal restrictions on these species to reduce water loss more effectively compared with wheat having lower ABA content (Nayysar, 2005). In maize seedlings, Wang et al (2008) assesed the inhibitory effect of ABA on the grain growth and reported that, at early stages, the endogenous ABA contents increased dramatically in leaves after 24 h of exposure to water stress, and then it remained high till the end. On the other hand, ABA content in seeds of wheat plants subjected to water deficit during grain filling showed variations.…”