Infuence of plant growth regulators onsex diferentiation and foral characteristicsof pomegranate fowers: a case ofbrassinosteroids

摘要

Te objective of the present study was to determine the efects of brassinosteroidapplication on the sex determination and foral growth of pomegranate fowers.Whole tress of Punica granatum ‘Mayho?-8’ were sprayed with 0.001, 0.01, and0.1 mg L?1 28-homobrassinolide (Hbr) at bud break. Te selection of fowers wasbased on the appearance of a visible pistil/stigma and shape of the ovary of intactflowers. Grouping of bisexual flowers was based on their flower position, i.e.,single, terminal, and lateral fowers, during the frst fush of fowering in mid-June.Approximately 20 days and 40 days afer spraying, 100 randomly chosen bisexualfowers per collection time were collected and measurements of foral parts wereimmediately taken. Te diferences between bisexual and functional male fowerswere not distinct enough to assert any signifcant efects from the diferent Hbrtreatments. Irrespective of treatments, the percentage of male fowers was higherthan that of bisexual fowers. Hbr treatments applied at the bud break period hadsignifcant efects only on bisexual fowers that developed as single fowers. Applying0.01 mg L?1 Hbr produced comparably lower percentages of single bisexual fowers(53.4%). Although the 0.1 and 0.001 mg L?1 Hbr treatments resulted in increasedpercentages of bisexual fowers, the diference was not signifcant. For the frst collection time (mid-June), the efects of Hbr concentration on the size of the foralparts for bisexual fowers were only signifcant in ovary width and stigma diameter.As the concentration decreased, smaller ovaries were obtained. During the secondfowering, application of 0.01 mg L?1 Hbr considerably increased the overall sizesof foral parts in bisexual fowers. Hbr might afect the ratio of fower formationin certain positions on a branch and could infuence the growth of foral parts inbisexual fowers. Further elucidation of these efects would help to better understandforal organ development in plants.