hrvatski

Uloga auksina i hormona stresa u odgovoru kupusnjača (Brassicaceae) na povišeni salinitet

Sažetak: Odgovor kineskog kupusa na kratkotrajni solni stres (24 h) istražen je na fiziološkoj, biokemijskoj, molekularnoj i hormonskoj razini. Uslijed solnog stresa inhibiran je rast korijena klijanaca, reducirana fotosintetska učinkovitost, povećana razina biokemijskih parametara stresa (GSH, fenolnih kiselina, prolina, Na+, ROS i peroksidacija lipida). Detektirane su značajne promjene u profilu hormona stresa: porast apscizinske kiseline i smanjenje jasmonata u listovima i korijenu, te sporadične promjene salicilne kiseline ovisno o biljnom tkivu. Uočene su značajne promjene u auksinskom metabolomu, na razini IAA biosinteze, oksidacije i konjugacije. Povećane razine transkripata gena za auksin- amidohidrolaze IAR3 i ILR1 ukazuju na ulogu reverzibilne konjugacije u homeostazi auksina u stresu. Komparativne hormonske analize kineskog, bijelog kupusa i raštike pokazale su korelaciju između profila fitohormona i tolerancije vrste na solni stres ; promjene u razinama hormona bile su izraženije kod osjetljivije vrste, kineskog kupusa, dok su tolerantnije vrste (bijeli kupus i raštika) pokazale određenu stabilnost u profilu hormona. Abstract: The short term salt stress response (24 h) of Chinese cabagge was investigated at the physiological, biochemical, hormonal and molecular levels. The root growth inhibition, photosynthesis reduction, elevated levels of biochemical stress parameters (GSH, phenolic acids, prolin, Na+, ROS and lipid peroxidation) were measured upon salt stress. Significant changes in the profile of stress hormones were identified: an increase of ABA and decrease of jasmonates in the leaves and roots, as well as sporadical changes of SA dependent on plant tissue. Furthermore, significant perturbations in auxin metabolome was induced by salt stress, at the level of IAA biosinthesis as well as oxidation and conjugation. An increase in the transcript level of auxin amidohydolases IAR3 and ILR1 was detected upon salt treatments, implicating the role of reversible conjugation in auxin homeostasis. Comparative hormonal analysis in Chinese cabbage, white cabagge and kale showed correlations between phytohormone profiles and salt stress tolerance ; more tolerant varieties (white cabbage and kale) showed more stability in hormonal profiles in comparison to sensitive species (Chinese cabbage)

Brassicaceae, solni stres, hormoni stresa, auksini, tolerancija

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