Are the fluorescence parameters of German chamomile leaves the first indicators of the anthodia yield in drought conditions?

Abstract

7-day soil drought followed by 7-day rehydration was applied to potted German chamomile (Chamomilla recutita) plants at the beginning of their generative stage. Plants of a wild type (WT), plus two diploid (2n) and two tetraploid (4n) genotypes were studied, in order to examine the alterations in chlorophyll (Chl) and carotenoids (Car) contents, and chlorophyll fluorescence (CF) parameters during water shortage and rehydration. The fresh mass of the anthodia after the recovery was also studied.WT plants adjust better to water stress than modern breeding genotypes, because drought resulted in the low fall in leaf water content of WT, the lowest decrease in the fresh mass of its anthodia (a 41% decrease from the control), and the most elastic response of the photosynthetic apparatus. 4n C11/2 strain plants suffered from the highest reduction in anthodia yield (87%), and had the lowest constitutive pigment contents. It was also the only genotype which revealed nontypical alterations in various CF parameters obtained on a dark-and light-adapted leaf. During drought, a big increase was noticed in minimal, maximal, and variable fluorescence of PSII reaction centres in the dark-adapted (F 0, F m and F v , respectively), and in the light-adapted state (F 0 ', F m ' and F v '). It was accompanied by the biggest decline in linear electron transport rate (ETR), quantum efficiency of PSII electron transport (Φ PSII ) and photochemical quenching coefficient (q P ). These alterations were prolonged to the stage when the normal leaf water content was retained. On the contrary, C6/2 strain plants had the highest constitutive Chl and Car contents, which additionally increased after rehydration, similarly to the values of F 0 , F m and F v , which reflects the high photosynthetic potential of this genotype. It was accompanied by the relatively high yield of its anthodia after drought. Considering the drop in the yield triggered by drought, it seems to be the only parameter which may be linked with the ploidy level.Although the yield formation of chamomile strains cannot simply be estimated by CF assay, this technique may serve as an additional tool in the selection of plants to drought. The following circumstances should be submitted; namely: measurement at the proper developmental stage of plants, in different water regimes, and an analysis of various CF parameters. The increase in F 0 and F 0 ', and the reduction in ETR, F v '/F m ', Φ PSII and q P values in response to water deficit should be an indicator of the impairment of the photosynthetic apparatus through drought.

Determination of parameters for selection of Eucalyptus clones tolerant to drought

“…The later and less intense effect of water deficiency observed on clone tolerant implies a lower sensitivity to the higher intensity and duration of the water deficits applied and indicates a greater drought tolerance compared with clone sensitive. The results concur also with the report of Zlatev and Yordanov (2004) in bean plants and that of Bączek-Kwinta et al (2011) in Chamomilla recutita. Tatagiba and Pezzopone (2007) however, found this variable to increase in the Eucalyptus plants during the dry season, which according to these authors implies that the restricted water supply caused no decrease in the photoreduction of quinone A (QA) and none in the electron flow between the photosystems in the clones studied.…”

Photosynthetic activity of variegated leaves of Coleus × hybridus hort. cultivars characterised by chlorophyll fluorescence techniques

“…In the absence of anthocyanins, green leaves utilise thermal energy dissipation via the xanthophyll cycle (Henry et al 2012, Logan et al 2015. In our experiment, it can be reflected by high NPQ values, and according to many authors (Maxwell and Johnson 2000, Montanaro et al 2007, Sofo et al 2009, Bączek-Kwinta et al 2011, it can be related to energy dissipation as heat via the xanthophyll cycle and other Cars, as well as conformational changes in PSII antennae (LHC).…”

“…The pigment content is the basis for the interpretation of some CF parameters, and then venturing estimation of the physiological state of photosynthetic apparatus (Lichtenthaler et al 2000, Baker 2008, Bączek-Kwinta et al 2011, Muniz et al 2014. In the creamy-yellow and pink sectors of leaves, the values of F0, F m , F 0 ', and F m ' were very low when compared to the other areas due to the low content of photosynthetic pigments.…”

Chlorophyll fluorescence imaging of cadmium-treated white cabbage plants

“…1.). The decrease in Fv/Fm suggests diminished photochemical capacity of PSII while Fv'/Fm' gives an important information about PSII maximum efficiency (Bączek-Kwinta et al, 2011b). ɸ PSII and qP can be interrelated with Fv/Fm (Maxwell and Johnson, 2000).…”