Chlorophyll Fluorescence as a Tool to Assess the Regeneration Potential of African Violet Leaf Explants

Abstract

Micropropagation of many ornamentals has enabled their efficient commercialisation and many problems have been solved by the elaboration of adequate culture protocols. Nevertheless, a non-destructive technique for monitoring the developmental progress of explants would be desirable. The present study focussed on the applicability of chlorophyll fluorescence in leaf explants of African violet (a Saintpaulia ionantha × confusa -hybrid) explanted onto Murashige and Skoog basic medium. The explants that survived on the medium without additional phytohormones had the capacity to develop further into two different kinds of explants: light green explants, characterized by a non-regular size growth and stiffer appearance, and dark green explants capable of organogenesis. Compared to the source leaves of African violet plants, explants were characterized by reduced chlorophyll (Chl) and carotenoid (Car) contents as well as a tendency towards a higher Car/Chl ratio. The Chl a/b ratio decreased significantly in the light green explants. A reduction of maximum quantum efficiency of photosystem II (F v /F m ) accompanied by a high percentage (> 50%) of thermal energy dissipation as a consequence of an elevated light intensity (800 µmol m -2 s -1 quanta) indicated photoinhibition in the light green explants, whereas in the dark green explants the largest percentage (> 50%) of the light energy was dissipated into the fraction of photon energy trapped by 'closed' photosystem II reaction centres. These results suggest that the capacity of organogenesis of leaf explants of African violet can be monitored using chlorophyll fluorescence, because it is related to modifications of the photosynthetic system.

Interactive effect of water and nitrogen fertilization improve chlorophyll fluorescence and yield of maize

“…However, the reasonable application of N combined with adequate irrigation can effectively improve the Fv / Fm and qP, thus reducing the NPQ of maize, these results are in line with the findings of Keutgen et al. (2016).…”

“…The Fv/Fm and qP decreased, and NPQ increased under environmental stress conditions, indicating the ability of PSII to decrease the use of light energy, resulting in low electron transfer efficiency for C fixation and the excess light energy lost in the form of heat dissipation. However, the reasonable application of N combined with adequate irrigation can effectively improve the Fv/Fm and qP, thus reducing the NPQ of maize, these results are in line with the findings of Keutgen et al (2016).…”

Induction of chlorophyll fluorescence use for assessment of functioning of Gentiana lutea L. plants photosynthetic apparatus in different conditions of culturing in vitro

“…В останнє десятиліття цей метод почали застосовувати й для рослин, що культивуються в умовах in vitro, оскільки ІФХ дозволяє оцінити ступінь залежності фотосинтетичних процесів від наявності/відсутності речовин-осмолітів у складі живильного середовища, їх концентрації, вмісту макро-та мікроелементів, інтенсивності світлового потоку в області фотосинтетично активної радіації (ФАР) тощо [2]. Крім того, цей метод часто пропонують використовувати для оцінки швидкості акліматизації отриманого біотехнологічними методами рослинного посадкового матеріалу до умов ex vitro [3]. Виходячи із вище зазначеного, мета роботи полягала у вивчені особливостей функціонування фотосинтетичного апарату in vitro рослин Gentiana lutea L. за різних умов освітлення та джерела карбону у складі живильного середовища за допомогою методу ІФХ.…”