Effect of exogenous salicylic acid or indole acetic acid on their endogenous levels, germination, and growth in maize

Abstract

Background Exogenous hormone applications modify the plant growth and development by inducing changes in their endogenous contents. However, it is not clear whether the effects of exogenous hormones on growth are direct or related with changes induced in endogenous hormones. Laboratory and greenhouse experiments were conducted to study the effect of exogenous salicylic acid (SA) or indole acetic acid (IAA) on endogenous levels in soaked seeds, 5-day-old seedlings, and in vegetative growth of foliar-sprayed plants. The effects of different concentrations of two hormones on germination and growth of maize were also studied. Results The effect of presoaking maize seeds in solutions of SA or IAA (0, 0.25, 0.5, 1, and 2 mM) on their endogenous contents in soaked seeds or in 5-day-old seedlings. Soaked seeds absorbed more SA than IAA. In young seedlings, the majority of two hormones which absorbed during seed soaking remained in the residual seeds. Presoaking seeds in SA or IAA solutions suppressed the growth of 5-day-old seedlings. In the greenhouse experiment, endogenous SA and IAA increased after spraying two compounds at 0.25–2 mM, peaking 2 days after treatment then decreased on. However, plants treated with SA at 1 mM or 2 mM continued to pose higher levels of endogenous SA, 8 days later. At 20 days after treatments, all tested concentrations of two hormones significantly increased the fresh and dry weights of the whole plant. These inducing effects disappeared 40 days after spraying. Conclusion The obtained results demonstrated the changes in endogenous SA and IAA in soaked seeds, seedling, and foliar-sprayed plants due to their exogenous application. However, concentrations of two hormones did not produce any permanent enhancement effects on germination and plant growth.

Comparative Study between Exogenously Applied Plant Growth Hormones versus Metabolites of Microbial Endophytes as Plant Growth-Promoting for Phaseolus vulgaris L.

“…In a comparative study, El-Mergawi and El-Wahed [ 92 ] conducted a greenhouse experiment to determine how foliar sprays of IAA or salicylic acid (SA) affect maize plant growth and the concentrations of endogenous IAA and SA. They reported that spraying plants with IAA and SA (0.25–2 mM) significantly increases the endogenous content of IAA and SA in a concentration-dependent manner, and the maximum increase (10–34%) was recorded after two days of treatment.…”

Salicylic Acid Induced Physiological Responses of Microchaete Sp. NCCU-342 Under PQ Stress

“…in cucumber under salt stress 31 and in Baikal skullcap under salt and drought stress 51 . Exogenous application of salicylic acid induced both IAA and SA in maize and cucumber under drought stress 52,53 .…”

Genome-Wide Characterization and Expression Analysis of KH Family Genes Response to ABA and SA in Arabidopsis thaliana

“…Also, 24 of 30 KH family genes contain ABA-responsive cis -elements (ABRE, AACCCGG), which indicated some KH family genes such as AtKH1 , AtKH9 can respond to ABA through these cis -elements. ABA and SA are the important hormones in plants, which are involved in diverse processes, such as germination and adaptation to different stresses [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ].…”

“…It can be produced when plants are exposed to drought, cold, or high osmotic pressure [ 23 , 24 ]. SA can promote seed germination under high salt concentration and osmotic pressure [ 25 ], while the highest concentration of SA inhibits the germination of maize seeds [ 26 ]. However, the KH family genes which are a response to ABA and SA are seldom investigated.…”