Growth regulators in reducing the size of orchid Fire-of-Star for commercialization in vase

Abstract

Fire-of-star (Epidendrum radicans Pav. ex Lindl.) is a terrestrial orchid, native to Brazil, tussocks with leafy stems, always with many adventitious roots, releasing its long inflorescence with about 1.0 m from the apex of the stem, showing great potential in floriculture, but long flowering stem complicates their marketing vase. The objective of this study was to evaluate the effect of paclobutrazol (PBZ) and mepiquat chloride (CLM) the reduction of the size of the orchid E. radicans. Plants with an average height of 15 cm were cultivated in a greenhouse with 50% shading. The growth regulators used were PBZ at doses of 0; 5; 10; 15 and 20 mg L-1, and the CLM at doses of 0; 1; 2; 3; 4 and 5 mg L-1. The frequency of application was fortnightly, totaling ten applications. The experiment was installed on a randomized complete blocks, one block to the PBZ with 5 treatments and 10 replications and another block to the CLM, with 6 treatments and 10 replications. Data were submitted to analysis of variance at 5% probability and significance when seen performed regression analysis. The variables evaluated were number shoots, plant height (cm), number of flower stems and leaf area. The results indicated that E. radicans treated with 5 mg L-1 PBZ were 50% lower in height than the control plants. When CLM treated with a dose of 1 mg L-1 plants were 25% lower in height than the control plants, maintaining its aesthetic characteristics suitable for marketing in vases. Growth regulators in the applied doses did not affect the number of shoots and flower stems. PBZ treated plants had 50% of their leaf area compared to control while those treated with CLM doses remained with the same average leaf area of control.