Influence of bud sett soaking with ethephon and its foliar application on growth, biochemical attributes and gene expression in sugarcane

Aim : The present study was carried out to evaluate the effect of sett soaking and foliar application of Ethephon treatment on sprouting, early growth characterisfics, SAI and SPS gene expression in bud and leaf tissues and important physio-biochemical parameters which essentially regulate the process of shoot and root growth in sugarcane. Methodology : Single bud setts of sugarcane were initially primed with graded level of Ethephon viz., 0, 100, 200 and 400 ppm for 24 hrs along with untreated control and planted in soil tray culture under net house. Data on bud sprouting, growth attributes were determined after 10 days. About 45 days after planting, second application of Ethephon was performed through foliar spray. Data on plant growth. sugar content, photosynthetic pigments, proline, total phenol and activity of peroxidase and nitrate reductase were estimated. SAI and SPS gene expression was also studied using gene specific primer pairs through qRT-PCR. Results : Ethephon treatment showed early and higher rate of bud sprouting, improved plant vigor, stalk height, fresh weight of root and shoot. Plants exposed to Ethephon exhibited higher chlorophyll content, proline. total phenol contents, activity of soluble acid invertase, nitrate reductase in vivo and peroxidase enzymes as compared to untreated plants. SAI and SPS gene expression was unregulated in treated bud and leaf tissues, respectively. Interpretation : Ethephon showed stimulatory effects on bud sprouting and early growth characteristics by modulating sugar hydrolysis and its transport to growing shoot and improving photosynthetic pigments and activity of nitrate assimilating enzyme in sugarcane plants.