Chlorophyll fluorescence as a tool for evaluation of drought stress in strawberry

Abstract

The effect of water deficit on chlorophyll fluorescence, sugar content, and growth parameters of strawberry (Fragaria×ananassa Duch. cv. Elsanta) was studied. Drought stress caused significant reductions in leaf water potential, fresh and dry masses, leaf area, and leaf number. A gradual reduction of photochemical quenching (q P ) and quantum efficiency (Φ PS2 ) was observed under drought stress while non-photochemical quenching (q N ) increased. Maximum efficiency of photosystem 2 (F v /F m ) was not affected by drought stress.Additional key words: Fragaria×ananassa; maximum efficiency of photosystem 2; photochemical and non-photochemical quenching; photosynthesis; water deficit.--Water deficiency is a limiting factor for plant growth and development as well as for a wide range of physiological processes such as photosynthesis. Chlorophyll (Chl) fluorescence provides useful information about leaf photosynthetic performance of many plants under drought stress (Baker and Rosenqvist 2004). However, studies on strawberry under drought stress are still limited and focus mainly to research on irrigation scheduling (Kruger et al. 1999). In order to better understand the response of strawberry to the onset and progress of drought stress we studied Chl fluorescence parameters in parallel with plant growth performance.A greenhouse experiment was conducted from October 2006 till February 2007 with the short day cultivar Fragaria×ananassa Duch. cv. Elsanta. Plants were grown in 3 000 cm³ pots in 80 : 20 % peat and perlite mixture at 18/14 °C day/night temperature, a daily average vapour pressure deficit (VPD) of 0.5−0.9 kPa, and a 16-h photoperiod. Natural day length was extended with metal halide lamps giving 30−40 µmol(PAR) m −2 s −1 at canopy level and daily average value of PAR ranged from 20 till 150 µmol m −2 s −1 . Plants were weekly supplied with 100 cm 3 of a standard nutrient solution for strawberry (Lieten 1995) and with rain water on the other days maintaining the pots close to field capacity. After nine weeks pots were assigned to a control and a drought stress (irrigation stop) treatment in a completely randomized block design with three replicates and 25 plants for each experimental plot. Volumetric substrate moisture content θ v (Theta probe, ML2X, Delta T Devices, Cambridge, UK) was recorded at hourly intervals. During the experiment, measurements were performed at days 1, 16, 27, 40, 44, and 51. The leaf water potential (Ψ w ) of the upper leaflet of the youngest fully developed leaf (n = 6 per experimental plot) was measured with a thermocouple psychrometer operating in the psychrometric mode between 08:00 and 09:00. Chl fluorescence was measured on the youngest fully expanded triplet leaf (n = 4 per experimental plot) using a portable fluorometer (PAM-2000, Walz, Effeltrich, Germany). Leaves were allowed to dark adapt for 20 min (Genty et al. 1998). Sugars of fully expanded leaves (n = 6 per experimental plot) were extracted with 80 % ethanol and analyzed by HPLC with pulsed amperometric detection (Dione...

Changes in chlorophyll content and fluorescence and fruit yield contributing traits in different genotypes of strawberry (Fragaria x ananassa DUCH.)

“…In the present work, the average values of potential quantum efficiency PS II (the parameter F v /F m ) were similar in the leaves of inbred and non-inbred plants. Similarly, R a z a v i et al [6] demonstrated in strawberry that maximum efficiency of photosystem II was not affected by drought stress.…”

“…In the study by R a z a v i et al [6], the effect of water deficit on chlorophyll fluorescence, sugar content, and growth parameters of strawberry was investigated. A gradual reduction of photochemical quenching and quantum efficiency was observed under drought stress in strawberry cv.…”

“…Chlorophyll fluorescence measurements are completely non-invasive, allowing photosynthesis to be studied in vivo. This method is particularly useful when the effects of different environmental factors [3,4,5,6], and biotic stress [7,8] on plants are studied. Inbreeding generally increases homozygosity in plants and more homozygous genotypes may be susceptible to environmental harshness. In contrast, outcrossing usually increases or maintains heterozygosity that tends to produce genotypes better able to buffer themselves against environmental variability [9].…”

Photosynthetic Performance of Maize Plants Under Salinity as Affected by Leaf H2o2 Priming

“…Simultaneous measurements of chlorophyll a fluorescence and gas exchange allow a better understanding of salt effects on the photosynthetic apparatus and have been very useful in the selection of plants more tolerant to adverse environmental conditions (Baker et al, 2008;Razavi et al, 2008;Lima Neto et al, 2014). In our study, in absence of NaCl, maize plants showed similar behavior even when submitted to pretreatment with H2O2.…”

Genotypic Diversity of Cross-Tolerance to Oxidative and Drought Stresses in Rice Seedlings Evaluated by the Maximum Quantum Yield of Photosystem II and Membrane Stability

“…However, because the F v /F m is hardly affected by mild drought stress or low irradiance (Baker and Rosenqvist, 2004;Razavi et al, 2008), the careful selection of an appropriate fluorescence parameter is important to evaluate the plant stress under the given environments. Furthermore, the value of F v /F m is dependent on the measurement of chlorophyll fluorescence emanated from only the top few layers of leaf chlorenchyma, whereas the oxidative damage occurs across the thickness of leaf (Maxwell and Johnson, 2000).…”