Data di Pubblicazione:
2009
Citazione:
Chitosan antitranspirant activity is due to abscisic acid-dependent stomatal closure / M. IRITI, V. PICCHI, M. ROSSONI, S. GOMARASCA, N. LUDWIG, M. GARGANO,F. FAORO. - In: ENVIRONMENTAL AND EXPERIMENTAL BOTANY. - ISSN 0098-8472. - 66:3(2009), pp. 493-500. [10.1016/j.envexpbot.2009.01.004]
Abstract:
Chitosan (CHT) is a natural compound able to activate the plant own defence machinery against pathogen
attacks and to reduce both transpiration and stomatal opening when applied as foliar spray. The data here
reported show that CHT-induced antitranspirant activity in bean plants is mediated by ABA, whose level
raised over threefold in treated leaves, 24 h after foliar spraying. This is thought to induce partial stomatal
closure via a H2O2-mediated process, as confirmed by scanning electron microscopy (SEM) and histocytochemistry,
and, in turn, a decrease of stomatal conductance to water vapor (Gw) and transpiration
rate (E), assessed by gas exchange measurements. The relatively high internal CO2 concentration (Ci)
values, suggest the occurrence of a slight decrease in carboxylation efficiency after CHT treatment, which
however did not prevail over stomatal limitations. The intrinsicwater use efficiency(WUEi) of CHT treated
plants was not statistically different from controls and the maximal photochemical efficiency (Fv/Fm) of
PSII was not affected. Moreover, CHT determined a stimulation of the xanthophyll cycle towards deepoxidation
state. On the whole, these results, besides confirming the effectiveness of CHT in reducing
plant transpiration, prove that the mechanism underlying this activity differs from that showed by the
commercial antitranspirant Vapor Gard® (VP). In fact, the efficacy of the latter is based on the formation of
a thin antitranspirant film over the leaf and not on the reduction of stomatal opening. Finally, suggestions
for possible use of the two antitranspirants in different environmental conditions are discussed.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Abscisic acid; Antitranspirant; Chitosan; Stomatal conductance; Vapor Gard; Water use efficiency
Elenco autori:
M. Iriti, V. Picchi, M. Rossoni, S. Gomarasca, N. Ludwig, M. Gargano, F. Faoro
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