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1

Morphological and physiological responses of some halophytes to salinity stress

100%

Mohammadi H., Kardan J.

Annales Universitatis Mariae Curie-Sklodowska, sectio C – Biologia

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2015

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vol. 70

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issue 2

EN

A pot experiment was conducted to examine whether the morphological and physiological characteristics of some halophytes may be affected by salt stress. For this purpose, a factorial experiment based on randomized complete block design was carried out with three replications. The treatments were some halophytes (Salicornia europaea, Atriplex leucoclada, and Kochia scoparia) and salinity stress levels [Electrical conductivity 0 (Hoagland’s solution), Hoagland’s solution consisting of 100, 200, 300 and 500 mM NaCl]. Among the halophytes tested, Salicornia europaea had significantly higher shoot and root of dry matters compared to the other halophytes in all salt treatments. Salinity stress resulted in an increase in photosynthetic pigments up to 200 mM and thereafter, it decreased in all of the studied plants. Photosynthetic pigments, ranked in a descending order, were high in Kochia scoparia, Salicornia europaea, and Atriplex leucoclada. In addition, salinity stress led to an enhancement in malondialdehyde (MDA) and H2O2. The tolerance of Salicornia europaea under high salinity stress was associated with low MDA and H2O2 contents as well as high contents of photosynthetic pigments. The shoot and root Na+ increased considerably by augmenting the salinity levels in all halophytic plants; however, there was a significant difference among halophytes at higher salinity levels. The shoot K+ decreased by increasing the salinity levels, but K+ partitioning pattern varied among the halophytes. Under saline conditions, the shoot and root Na+/K+ ratio of all halophytes grew. The highest and the lowest of Na+ were observed in Salicornia europaea and Kochia scoparia, respectively. Thus, the Na+/K+ ratio could be considered as an indicator of salt evaluation. Nitrogen, protein content, dry matter digestibility (DMD), and metabolizable energy (ME) were high in Salicornia europaea plants in comparison to other plants at 200–500 mM salinity levels; in contrast, acid detergent fiber (ADF) and netural detergent fiber (NDF) were low. According to the results of this study, the tolerance of halophytes towards NaCl is possibly due to the differences in damage from reactive oxygen species (ROS), especially H2O2, and toxicity to metabolism Na+.

2

Fluorescencja chlorofilu w odpowiedzi pszenicy na egzogenną aplikację regulatorów wzrostu w stresie suszy

81%

Mohammadi H., Janmohammadi M., Sabaghnia N.

Annales Universitatis Mariae Curie-Sklodowska, sectio C – Biologia

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2015

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vol. 70

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issue 1

EN

Drought stress negatively affects plant photosynthesis and disturbs the electron transport activity. Evaluation of the chlorophyll fluorescence parameters might reflect influence of the environmental stress on plants and can be applied as an indicator of the primary photochemistry of photosynthesis. In current study the effect of foliar application of benzylaminopurine (BAP, a synthetic cytokinin) and abscisic acid (ABA) on chlorophyll fluorescence parameters of relatively drought tolerant (Pishtaz) and susceptible (Karaj3) bread wheat genotypes under well watered and terminal water deficit condition have been evaluated. Terminal drought was induced by withholding water at anthesis stage (Zadoks scale 65). Results showed that coefficient of non-photochemical quenching of variable fluorescence (qN), quantum yield of PS II photochemistry (ΦPSII) and photochemical quenching (qP) were affected by hormone spray treatments. So that evaluation of parameters at 7 day after foliar treatments revealed that ABA significantly increased electron transport rate (ETR) and qN while considerably decreased ΦPSII, gs and maximum quantum yield of photosystem II (Fv/Fm). However exogenous application of cytokinin could increase gs, Fv/Fm and ΦPSII and the highest value of these parameters was recorded in cytokinin treated plants of Pishtaze cv. under well watered condition. Nevertheless, evaluation of the parameters in different periods after spraying showed that with approaching the maturity stage some traits like as gs, Fv/Fm and ETR significantly decreased in both genotypes. Evaluation of gs and Chlorophyll fluorescence parameters of genotypes between different irrigation levels showed that although cv. Pishtaz showed higher performance of PSII under well watered condition, it failed to maintain its superiority under stress condition. This finding suggests that some more responsive parameter like gs, Fv/Fm and ΦPSII can be considered as reliable indicator for understanding the biochemical and physiological effects of exogenous application of phytohormones under terminal drought stress.

PL

Stres suszy wpływa negatywnie na fotosyntezę roślin oraz zakłóca transport elektronów. Ocena parametrów fluorescencji chlorofilu może odzwierciedlać wpływ stresu środowiskowego na rośliny i może być stosowana jako wskaźnik pierwotnych reakcji fotochemicznych fotosyntezy. W prezentowanych badaniach oceniano wpływ dolistnego stosowania benzyloaminopuryny (BAP, syntetyczna cytokinina) i kwasu abscysynowego (ABA) na parametry fluorescencji chlorofilu w stosunkowo odpornych na suszę (Pishtaz) i podatnych (Karaj3) genotypach pszenicy w warunkach dobrego nawodnienia i skrajnego deficytu wody. Krańcową suszę wywoływano w fazie kwitnienia (65 w skali Zadoks). Wykazano, że współczynnik niefotochemicznego wygaszania fluorescencji (qN), wydajność kwantowa reakcji fotochemicznych PS II (ΦPSII) i fotochemiczne wygaszanie (qP) ulegały zmianom po opryskiwaniu liści hormonami. Ocena parametrów po 7 dniach od dolistnego podania hormonu wykazała, że ABA znacząco zwiększa sprawność transportu elektronów (ETR) i qN, znacznie zmniejsza ΦPSII, gs i maksymalną wydajność kwantową fotosystemu II (Fv/Fm). Jednak egzogenne zastosowanie cytokininy może zwiększyć gs, Fv/Fm i ΦPSII, a najwyższą wartość tych parametrów odnotowano w traktowanych cytokininą roślinach odmiany Pishtaze w warunkach dobrego nawodnienia. Ocena parametrów w różnych okresach po oprysku wykazała, że w bardziej dojrzałych roślinach wskaźniki takie jak gs, Fv/Fm i ETR znacznie zmniejszyły się w obu genotypach. Ocena gs i parametrów fluorescencji chlorofilu genotypów w warunkach różnych poziomów nawodnienia wykazała, że chociaż genotypy Pishtaz wykazały wyższą wydajność PSII w stanie dobrego nawodnienia, nie udało się utrzymać przewagi w warunkach stresu. Odkrycie to sugeruje, że niektóre bardziej czułe parametry takie jak gs, Fv/Fm i ΦPSII mogą być wiarygodnym wskaźnikiem dla zrozumienia biochemicznych i fizjologicznych efektów egzogennego stosowania fitohormonów w warunkach krańcowego stresu suszy.

3

Morphophysiological and biochemical response of savory medicinal plant using silicon under salt stress

81%

Mohammadi H., Hazrati S., Parviz L.

Annales Universitatis Mariae Curie-Sklodowska, sectio C – Biologia

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2017

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vol. 72

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issue 2

EN

Salt stress is one of the most important factors limiting the growth and yield of plants around the world. However, silicon can reduce the harmful effects of salt stress on plants. For this purpose, an experiment was conducted in a factorial arrangement on randomized complete block design with three replications in a research greenhouse on the Satureja hortensis medicinal plant. Experimental treatments consisted of two salinity levels (control and 100 mM) and potassium silicate (Si) at three levels (0, 1, and 2 mM). The results showed that salinity reduced shoot dry weight, photosynthetic pigments and potassium content of shoot. However, sodium, proline, MDA, and H2O2 contents in shoot increased. The highest shoot dry weight, photosynthetic pigment content, proline, RWC, and the lowest content of MDA and H2O2 of the shoot were observed with Si application under salt stress and non-salt stress conditions. The highest yield of essential oil was also observed with Si application under salt stress and non-salt stress conditions. Therefore, the use of silicon in salt stress condition not only minimizes the harmful effects of salt stress by increasing the K+/Na+ ratio and improving the morphological and physiological traits of the Satureja hortensis medicinal plant but also improves the essential oil yield of this medicinal plant in salt stress and non-salt stress conditions.

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3 Annales Universitatis Mariae Curie-Sklodowska, sectio C – Biologia

3 Mohammadi H.

1 Hazrati S.

1 Janmohammadi M.

1 Kardan J.

1 Parviz L.

1 Sabaghnia N.

1 2017

2 2015

Morphological and physiological responses of some halophytes to salinity stress

Fluorescencja chlorofilu w odpowiedzi pszenicy na egzogenną aplikację regulatorów wzrostu w stresie suszy

Morphophysiological and biochemical response of savory medicinal plant using silicon under salt stress