Physiological function of non-glandular trichomes in red clover (Trifolium pratense L.)

Abstract

The objective of the trial was to study the physiological function and potential ecological significance of non-glandular trichomes in red clover based on their relation to the leaf transpiration intensity. The transpiration rate, relative water content and water deficit of the leaves were recorded in field-grown, high and slightly pubescent genotypes. According to results, the presence of nonglandular epidermal trichomes on the leaf surface of red clover was a micromorphological trait related to the regulation of leaf transpiration in stressful conditions. Non-glandular trichomes significantly enhanced water retention of the leaf tissue at high leaf water deficit. In the environmental conditions, limiting leaf evaporation, the pubescent genotypes displayed higher levels of transpiration. It can be suggested that the non-glandular trichomes in red clover are morphological structures supporting the function of leaf stoma apparatus. A positive relation between the degree of pubescence and resistance to powdery mildew was established under natural conditions.Cilj ovog ogleda je bio proucavanje fizioloske funkcije i potencijalnog ekoloskog znacaja nezlezdanih trihoma kod crvene deteline na osnovu njihovog odnosa prema intenzitetu transpiracije lista. Intenzitet transpiracije, relativni sadrzaj vode i deficit vode u listovima su praceni kod genotipova sa izrazenim i slabo prisutnim trihomima, gajenim u poljskim uslovima. Prema rezultatima, prisustvo nezlezdanih epidermalnih trihoma na povrsini listova crvene deteline je mikromorfoloska osobina koja je povezana sa regulacijom transpiracije lista u uslovima stresa. Nezlezdani trihomi znacajno povecavaju zadrzavanje vode u tkivu lista pri visokom deficitu vode. U uslovima spoljasnje sredine, ogranicavanjem isparavanja sa povrsine lista, maljavi genotipovi su ispoljili veci intenzitet transpiracije. Na osnovu toga moze se pretpostaviti da su nezlezdani trihomi kod crvene deteline morfoloske strukture koje potpomazu funkciju stominog aparata lista. Ustanovljen je pozitivan odnos izmedju stepena zastupljenosti trihoma i otpornosti na pepelnicu u prirodnim uslovima.