Akademos: Revista de Ştiinţă, Inovare, Cultură şi Artă (Mar 2024)
ANALYSIS OF THE CYTOHISTOLOGICAL PHENOTYPE OF ANTHERS IN SUNFLOWER WITH ASI-AG 3 IN THE CON- TEXT OF THE PET1 MYTOTYPE AND THE ALLELIC GENOTYPE FOR THE Rf1 GENE
Abstract
Microsporogenesis and male gametogenesis are processes that, although under tight morphogenetic control, can often be affected by deviations of internal or external stimuli causing androsterility. The article examines the cytohistological phenotypes of sunflower anthers with gibberellin induced androsterility in plants with different mitotype and allelic genotype for the Rf1 gene, in comparison with the cytohistological phenotypes of fertile and sterile anthers (ASC-PET1). The treatment with gibberellic acid (AG 3 , 0.01%) was carried out by spraying the inflorescence at the budding stage. Cytological samples and those with semi-thin anther sections were analysed by light microscopy. It was determined that the gametocidal effects induced by AG3 associated with degenerative and early apoptotic events in tapetum cells were more severe in plants with sterile cytoplasm and nuclear Rf1 genes compared to those with fertile cytoplasm and no fertility-restoring genes. In plants with ASC, the exogenous gibberellin stimulus does not cause any visible compensatory events of the sterile phenotype, on the contrary, the effects of microsporogenesis inhibition are more temporally advanced, with sporogenous and sporophytic tissue cells showing various lesions in the premeiosis. The general common and differentiation characteristics found at the androsteril phenotypes suggest interactions be- tween orfH522 and Rf1 gene expression products of negative feedback type in untreated plants and positive feedback type in AG3 -treated ones. The research is relevant in the context of elucidating the physiological regulatory processes of the sensitivity of male gametophyte development to various stress conditions, which prospectively makes possible regulatory intervention in plants with different androsterility/androfertility control systems.
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