Development and accumulation of ABA in fluridone‐treated and drought‐stressed Vicia faba plants under different light conditions

Abstract

The effects of fluridone on guard cell morphology, chloroplast ultrastructure and accumulation of drought stress‐induced abscisic acid (ABA) were studied in Vicia faba L. plants grown under different light conditions. Drought stress was induced by allowing the leaves to lose 12% of their fresh weight. The appearance of defective and undeveloped stomata, and chloroplasts with a destroyed thylakoid membrane system was found in fluridone‐treated plants grown at a photosynthetic photon flux (PPF) of 600 μmol m‐2 s‐1. Plants grown at a PPF of 40 μmol m‐2 s‐1 had diminished levels of ABA after imposition of dehydration. Fluridone treatment reduced the level of ABA in both unstressed and dehydrated leaves. Accumulation of ABA in the control plants was considerably reduced when they were exposed to dark periods of 24, 48 and 72 h just before imposition of the stress. Twenty‐four hours after the dark treatment dehydration of the leaves resulted in a 3‐fold decrease in the level of stress‐induced ABA, and 72 h after dark treatment the amount of stress‐induced ABA approximated the prestressed values. Fluridone‐treated plants failed to accumulate ABA under water stress. In addition to functionally active chloroplasts, well‐developed and functional stomata are required for drought stress to elicit a rise in ABA.

The effect of fluridone and flurochloridone on the incidence of albinism in pea (Pisum sativum) and on the abscission of leaves of privet (Ligustrum vulgare)

“…For instance, it was confirmed that due to the effect of ABA seed dormancy was enhanced (Garello and Page-Degivry 1999, Grappin et al 2000), as well as resistance to drought (Popova 1998, Popova andRiddle 1996), to frost (Yu and Griffith 2001) and salinity (Bellaire et al 2000). In contrast, by means of fluridone the role of ABA in root gravitropism was not confirmed (Moore 1990).…”

“…Fluridone inhibits the synthesis not only of ABA but also of carotenoids and chlorophyll (Popova 1998) and this may result in carotenoid and chlorophyll deficiency (Gamble and Mullet 1986) or even destruction of the inner structure of chloroplasts (Popova and Riddle 1996). The occurrence of albinism after fluridone application was described, for instance, in Allium wakegi (Yamazaki et al 1999), barley (Popova 1998) and alfalfa (Meyers et al 1996) largely in association with investigations of dormancy or effects of stress.…”

“…The relation of fluridone to this synthesis has been explored, for instance, in rape and sugar beet (Ragolsky andThorpe 1989), bean (Popova andRiddle 1996), alfalfa (Meyers et al 1996) and barley (Popova 1998). Our next task was to discover the effect of various methods and forms of application of fluridone on chlorophyll synthesis, seedling growth and on the occurrence of albinism in pea.…”

Effects of Fluridone Treatment on Seed Germination and Dormancy-associated Gene Expression in an Ornamental Peach (<i>Prunus persica</i> (L.) Batsch)

“…It also inhibits ABA biosynthesis in plants (Popova and Riddle, 1996;Stewart and Voetberg, 1987;Xu and Bewley, 1995;Yoshioka et al, 1998), and it has been shown to break seed dormancy in several plant species (Ali-Rachedi et al, 2004;Chen et al, 2007;Grappin et al, 2000;Kusumoto et al, 2006). For example, in Prunus campanulata, 50 μM fluridone increased the germination rate from 21% to 94.7% for true seeds (without an endocarp) (Chen et al, 2007).…”

Temperature sensitivity of photosystem II in isolated thylakoid membranes from fluridone-treated pea leaves

“…Our previous investigation showed that fluridone can also alter PSII antenna complex organization (Dankov et al, 2009). The fluridone-induced changes in the photosynthetic apparatus influence plant development, leaf anatomy, and plastid ultrastructure (Popova and Riddle, 1996).…”