https://cyberleninka.org/article/n/704030.pdf

Environmental impact of estrogens on human, animal and plant life: A critical review.

Plants are frequently exposed to a plethora of unfavorable or even adverse environmental conditions, termed as abiotic stresses (such as salinity, drought, heat, cold, flooding, heavy metals, ozone, UV radiation, etc.) and thus they pose serious threats to the sustainability of crop yield. Soil salinity, one of the most severe abiotic stresses, limits the production of about 6 % of the world’s total land and 20 % of irrigated land (17 % of total cultivated areas) and negatively affects crop production worldwide. On the other hand, increased salinity of agricultural land is expected to have destructive global effects, resulting in up to 50 % land loss by the next couple of decades. The adverse effects of salinity have been ascribed mainly to an increase in sodium (Na+) and chloride (Cl–) ions and hence these ions produce the critical conditions for plant survival by intercepting different plant mechanisms. Both Na+ and Cl– produce many physiological disorders in plants but Cl– is the most dangerous. A plant’s response to salt stress depends on the genotype, developmental stage, as well as the intensity and duration of the stress. Increased salinity has diverse effects on the physiology of plants grown in saline conditions and in response to major factors like osmotic stress, ion-specificity, nutritional and hormonal imbalance, and oxidative damage. In addition to upper plant parts, salinity also affects root growth and physiology and their function in nutrient uptake. The outcome of these effects may cause the disorganization of cellular membranes, inhibit photosynthesis, generate toxic metabolites and decline nutrient absorption, ultimately leading to plant death. In recent decades, exogenous protectants such as osmoprotectants, phytohormones, signaling molecules, polyamines, antioxidants and various trace elements have been found effective in plants in mitigating the salt induced damages. These protectants showed the capacity to enhance the plants’ growth, yield as well as stress tolerance under salinity. In this chapter we attempt to summarize differential responses of plants to salinity with special reference to growth, physiology and yield. Further, we have discussed the progress made in using exogenous protectants to mitigate salt-induced damages in plants.

https://www.springer.com/cda/content/document/cda_downloaddocument/9781461447467-c1.pdf

Plant Response to Salt Stress and Role of Exogenous Protectants to Mitigate Salt-Induced Damages

The geomagnetic field (GMF) is a natural component of our environment. Plants, which are known to sense different wavelengths of light, respond to gravity, react to touch and electrical signaling, cannot escape the effect of GMF. While phototropism, gravitropism, and tigmotropism have been thoroughly studied, the impact of GMF on plant growth and development is not well-understood. This review describes the effects of altering magnetic field (MF) conditions on plants by considering plant responses to MF values either lower or higher than those of the GMF. The possible role of GMF on plant evolution and the nature of the magnetoreceptor is also discussed.

/pdf/magnetic-field-effects-on-plant-growth-development-and-4zz2wwzn1b.pdf

Magnetic field effects on plant growth, development, and evolution.

We investigated the possible mediatory role of melatonin in protecting wheat plants from cold stress. Ten-day-old wheat seedlings were pretreated with 1 mmol l−1 melatonin for 12 h and subsequently exposed to stress conditions at 5/2 °C (day/night) for 3 days. Cold stress caused serious reductions in leaf surface area, water content, and photosynthetic pigment content, whereas melatonin application attenuated these reductions. Accumulation of reactive oxygen species (ROS), including superoxide and hydrogen peroxide, was very high in cold-stressed plants and caused lipid peroxidation in membranes. Concomitantly, ROS damaged the DNA profile and negatively influenced expression and/or activity of many enzymes, including RuBisCo. When compared to controls, cold-stressed plants had higher activities of the antioxidant enzymes superoxide dismutase, guaicol peroxidase, ascorbate peroxidase, and glutathione reductase and higher levels of the antioxidant compounds total ascorbate, reduced ascorbate, total glutathione, reduced glutathione, and phenolic substances; however, this elevation could not cope with the destructive effects of cold stress. Melatonin-pretreated plants exhibited greater increases in these parameters comparison with untreated cold-stressed plants. Isozyme bands monitored in native gel and RuBisCo expression supported these changes. Also, due to the cold-induced increase in dehydroascorbate and oxidized glutathione, the corrupted redox status in the cell was ameliorated by melatonin application. Similarly, levels of the osmoprotectants total soluble protein, carbohydrate, and proline were also increased by cold stress; however, melatonin-applied seedlings had a higher content of these solutes in comparison to untreated cold-stressed plants. We suggest that melatonin can improve plant resistance to cold stress in wheat seedlings by directly scavenging ROS and by modulating redox balance and other defence mechanisms.

The regulatory effect of melatonin on physiological, biochemical and molecular parameters in cold-stressed wheat seedlings

Strategies to enhance the production of photosynthetic pigments and lipids in chlorophycae species.

Magnetic field (MF) can have different effects on plant metabolism depending on its application style, intensity, and environmental conditions. This study reports the effects of different intensities of static MF (4 or 7 mT) on seed germination and seedling growth of bean or wheat seeds in different media having 0, 2, 6, and 10 atmosphere (atm) osmotic pressure prepared with sucrose or salt. The germination percentages of the treated seeds were compared with untreated seeds germinated in different osmotic pressure during 7 days of incubation. The application of both MFs promoted the germination ratios of bean and wheat seeds, regardless of increasing osmotic pressure of sucrose or salt. Growth data measured on the 7th day showed that the treated plants grew faster than control. After 7 days of incubation, the mean length of treated seedlings was statistically higher than control plants in all the media. The greatest germination and growth rates in both plants were from the test groups exposed to 7 mT MF. Strikingly, effects of static MF on germination and growth increased positively with increasing osmotic pressure or salt stress compared to their respective controls. On the other hand, MF application caused an increase in dry biomass accumulation of root and shoots of both seedlings; however, this effect was found statistically important in all the conditions for wheat but not for bean, in general.

Acceleration of Germination and Early Growth of Wheat and Bean Seedlings Grown Under Various Magnetic Field and Osmotic Conditions

http://yoksis.bilkent.edu.tr/pdf/files/10.1016-j.jplph.2012.03.011.pdf

Analysis of apoplastic and symplastic antioxidant system in shallot leaves: impacts of weak static electric and magnetic field.

In the present study, it was aimed to investigate the influence of exogenous mammalian sex hormones (MSH) (progesterone, β-estradiol and androsterone) on the morphological (root and shoot growth) and biochemical parameters (protein and sugar content, antioxidant enzyme activities, and lipid peroxidation and H2O2 levels) of chickpea (Cicer arietinum L.) plants growing under control conditions. The solutions of hormones prepared at different concentrations (10−4, 10−6, 10−9, 10−12 and 10−15 M) were sprayed once on the leaves of 7-day plants. The plants were harvested on 18 days after the hormone treatment. Although all of the hormones at the tested concentrations significantly increased plant growth, soluble protein and sugar contents, and antioxidant enzyme activities [superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT)], they decreased H2O2 content and lipid peroxidation level when compared with control plants. The activities of SOD, POX and CAT reached to the highest levels at 10−6 M for progesterone, and 10−9 M for β-estradiol and androsterone, which maximum growth, protein and sugar contents were determined. The same concentrations also resulted in the lowest levels for H2O2 content and lipid peroxidation. It can be interpreted that the MSH improve plant growth and development by affecting some biochemical parameters including antioxidative system.

Mammalian sex hormones stimulate antioxidant system and enhance growth of chickpea plants

Salicylic acid (SA), a plant phenolic compound, is now considered as a hormone-like endogenous regulator, and there is a great interest to clarify its role in the defence mechanisms against biotic and abiotic stressors. In this study, investigations on the effects of foliar-applied SA on salt sensitivity, hydrogen peroxide (H2O2) generation and activities of antioxidant enzymes like peroxidase (POX) and catalase (CAT) in plant tissues under salt stress was performed. SA treatment significantly increased the fresh and dry weights in both root and shoots of wheat plants under salt stress. Similarly, POX and CAT activities were also augmented by SA treatment. While the highest POX activity was recorded at SA+120 mM NaCl, CAT activity also exhibited an increase compared to salt treatment without SA. In parallel to increasing antioxidative activity, SA treatment decreased H 2O2 content when compared to plants growing under salt stress without SA. The results revealed that salt-induced deleterious effect in wheat seedlings were significantly alleviated by the SA treatment. SA can be used as a signal molecule to investigate plant defense to abiotic stress. After the application of SA, increasing tolerance of wheat seedlings to salt stress may be related to increases in antioxidative enzyme activitiy.

/pdf/effects-of-salicylic-acid-on-wheat-salt-sensitivity-1dqe2vbgr8.pdf

Rahmi Dumlupinar

Papers

Acceleration of Germination and Early Growth of Wheat and Bean Seedlings Grown Under Various Magnetic Field and Osmotic Conditions

Analysis of apoplastic and symplastic antioxidant system in shallot leaves: impacts of weak static electric and magnetic field.

Mammalian sex hormones stimulate antioxidant system and enhance growth of chickpea plants

Effects of salicylic acid on wheat salt sensitivity

Modulation of alternative oxidase to enhance tolerance against cold stress of chickpea by chemical treatments