scholarly journals Antagonistic effects of drought and sand burial enable the survival of the biocrust moss <i>Bryum argenteum</i> in an arid sandy desert

2018 ◽  
Vol 15 (4) ◽  
pp. 1161-1172 ◽  
Author(s):  
Rongliang Jia ◽  
Yun Zhao ◽  
Yanhong Gao ◽  
Rong Hui ◽  
Haotian Yang ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Photochemical Efficiency ◽  
Soil Surface ◽  
Sandy Desert ◽  
Negative Effects ◽  
Regeneration Potential ◽  
Sand Burial ◽  
Psii Photochemical Efficiency ◽  
Effects Of Drought ◽  
Chlorophyll A Content

Abstract. Biocrust moss is an essential soil surface bio-cover. It can represent the latest succession stage among the diverse range of surface-dwelling cryptogams (e.g., cyanobacteria, green algae, and lichen, which are also referred to as biocrusts), and it can make a major contribution to soil stability and fertility in many arid sandy desert ecosystems. The soil surface represents a very large ecological niche that is poikilohydric in nature. Biocrust moss is therefore highly susceptible to drought and sand burial, which are two ubiquitous stressors in arid sandy deserts. However, little information is available regarding the mechanism by which biocrust moss can survive and flourish in these habitats when stressed simultaneously by the two stressors. The combined effects of drought and sand burial were evaluated in a field experiment using the predominant biocrust moss, Bryum argenteum Hedw., in the Tengger Desert, China. Drought was simulated by applying distilled water in three artificial rainfall regimes at 8-day intervals in spring and autumn: 4 and 6 mm (average rainfall, control), 2 and 3 mm (double drought), and 1 and 1.5 mm (4-fold drought), respectively. The effect of sand burial was determined by applying six treatments, i.e., sand depths of 0 (control), 0.5, 1, 2, 4, and 10 mm. The four parameters of chlorophyll a content, PSII photochemical efficiency, regeneration potential, and shoot upgrowth were evaluated in the moss. It was found that the combined effects of drought and sand burial did not exacerbate the single negative effects of the four parameters tested. Drought significantly ameliorated the negative effects of deep-sand burial on the retention of chlorophyll a content, PSII photochemical efficiency, and the regeneration potential of B. argenteum. Sand burial diminished and even reversed the negative effects of drought on the maintenance of chlorophyll a content, PSII photochemical efficiency, and regeneration potential. Although drought and sand burial imposed an additive negative effect on shoot upgrowth, which suggested a trade-off between growth ability and stress tolerance, their mutually antagonistic effect on the physiological vigor of B. argenteum provided an opportunity for the biocrust moss to overcome the two co-occurring stressors. In addition to providing a strong stress tolerance, drought and sand burial may provide an important mechanism for the biodiversity maintenance of biocrust mosses in arid sandy ecosystems.

scholarly journals The mutually antagonistic effect of drought and sand burial enables the biocrust moss <i>Bryum argenteum</i> Hedw. to survive the two co-occurring stressors in an arid sandy desert

2017 ◽  
Author(s):  
Rongliang Jia ◽  
Yun Zhao ◽  
Yanhong Gao ◽  
Rong Hui ◽  
Haotian Yang ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Photochemical Efficiency ◽  
Soil Surface ◽  
Antagonistic Effect ◽  
Negative Effects ◽  
Regeneration Potential ◽  
Sand Burial ◽  
Psii Photochemical Efficiency ◽  
Effects Of Drought ◽  
Chlorophyll A Content

Abstract. Biocrust moss is an essential soil surface bio-cover. It represents the highest succession stage among the diverse range of surface-dwelling cryptogams (e.g., cyanobacteria, green algae, and lichen, which are also referred to as biological soil crusts) and makes a major contribution to soil stability and fertility throughout arid desert ecosystems. The soil surface represents a small ecological niche that is poikilohydric in nature. Biocrust moss is therefore highly susceptible to drought and sand burial, which are two ubiquitous stressors in arid sandy deserts. However, little information is available regarding the mechanism by which biocrust moss can survive and flourish in these habitats when stressed simultaneously by the two stressors. The combined effects of drought and sand burial were evaluated in a field experiment using the predominant biocrust moss, Bryum argenteum Hedw., in the Tengger Desert, China. Drought was simulated by applying distilled water in three artificial rainfall regimes at 8-day intervals in spring and autumn: 4 and 6 mm (average rainfall, control), 2 and 3 mm (double drought), and 1 and 1.5 mm (fourfold drought), respectively. The effect of sand burial was determined by applying six treatments, i.e., sand depths of 0 (control), 0.5, 1, 2, 4, and 10 mm. The four parameters of chlorophyll a content, PSII photochemical efficiency, regeneration potential, and shoot upgrowth were evaluated in the moss. It was found that the combined effects of drought and sand burial did not exacerbate the single negative effects of the four parameters tested. Drought significantly ameliorated the negative effects of deep sand burial on the retention of chlorophyll a content, PSII photochemical efficiency, and regeneration potential of B. argenteum. Sand burial diminished and even reversed the negative effects of drought on the maintenance of chlorophyll a content, PSII photochemical efficiency, and regeneration potential. Although drought and sand burial imposed an additive negative effect on shoot upgrowth, which suggested a trade-off between growth ability and stress tolerance, their mutually antagonistic effect on the physiological vigor of B. argenteum provided an opportunity for the biocrust moss to overcome the two co-occurring stressors. In addition to providing a strong stress tolerance, drought and sand burial may provide an important mechanism for the biodiversity maintenance of biocrust mosses in arid sandy ecosystems.

scholarly journals Is Your Moss Alive during Active Biomonitoring Study?

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2389
Author(s):  
Paweł Świsłowski ◽  
Arkadiusz Nowak ◽  
Małgorzata Rajfur
Keyword(s):  
Chlorophyll Content ◽  
Chlorophyll A ◽  
Photochemical Efficiency ◽  
Negative Effects ◽  
Bioindicator Species ◽  
Active Biomonitoring ◽  
Flame Atomic Absorption ◽  
Flame Atomic Absorption Spectrometer ◽  
Living Organisms ◽  
Student’S T

Biomonitoring was proposed to assess the condition of living organisms or entire ecosystems with the use of bioindicators—species sensitive to specific pollutants. It is important that the bioindicator species remains alive for as long as possible while retaining the ability to react to the negative effects of pollution (elimination/neutralization of hazardous contaminants). The purpose of the study was to assess the survival of Pleurozium schreberi moss during exposure (moss-bag technique) based on the measurement of the concentration of elements (Ni, Cu, Zn, Cd, and Pb), chlorophyll content, and its fluorescence. The study was carried out using a CCM-300 portable chlorophyll content meter, portable fluorometer, UV-Vis spectrophotometer, and a flame atomic absorption spectrometer. As a result of the laboratory tests, no significant differences were found in the chlorophyll content in the gametophytes of mosses tested immediately after collection from the forest, compared to those drying at room temperature in the laboratory (p = 0.175 for Student’s t-test results). Mosses exposed using the moss-bag technique of active biomonitoring were characterized by a drop in the chlorophyll content over 12 weeks (more than 50% and 60% for chlorophyll-a and chlorophyll-b, respectively). Chlorophyll content in mosses during exposure was correlated with actual photochemical efficiency (yield) of photosystem II (calculated value of Pearson’s linear correlation coefficient was 0.94—there was a significant correlation between chlorophyll a and yield p = 0.02). The highest metal increases in mosses (RAF values) were observed for zinc, lead, and copper after the second and third month of exposure. The article demonstrates that the moss exposed in an urbanized area for a period of three months maintains the properties of good bioindicator of environmental quality.

Involvement of dehydrin proteins in mitigating the negative effects of drought stress in plants

2021 ◽  
Author(s):  
Riyazuddin Riyazuddin ◽  
Nisha Nisha ◽  
Kalpita Singh ◽  
Radhika Verma ◽  
Ravi Gupta
Keyword(s):  
Drought Stress ◽  
Negative Effects ◽  
Effects Of Drought

Penconazole and calcium ameliorate drought stress in canola by upregulating the antioxidative enzymes

2020 ◽  
Vol 47 (9) ◽  
pp. 825 ◽  
Author(s):  
Maryam Rezayian ◽  
Vahid Niknam ◽  
Hassan Ebrahimzadeh
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Antioxidative Enzymes ◽  
Proline Content ◽  
Fresh Weight ◽  
Negative Effects ◽  
Mda Content ◽  
Effects Of Drought

The aim of this research was to gauge the alternations in the lipid peroxidation and antioxidative enzyme activity in two cultivars (cv. RGS003 and cv. Sarigol) of canola under drought stress and drought tolerance amelioration by penconazole (PEN) and calcium (Ca). Plants were treated with different polyethylene glycol (PEG) concentrations (0, 5, 10 and 15%) without or with PEN (15 mg L–1) and Ca (15 mM). The Ca treatment prevented the negative effects of drought on fresh weight (FW) in RGS003 and Sarigol at 5 and 15% PEG respectively. Ca and PEN/Ca treatments caused significant induction in the proline content in Sarigol at 15% PEG; the latter treatment was accompanied by higher glycine betaine (GB), lower malondialdehyde (MDA) and growth recovery. Hydrogen peroxide (HO2) content in Sarigol was proportional to the severity of drought stress and all PEN, Ca and PEN/Ca treatments significantly reduced the H2O2 content. PEN and PEN/Ca caused alleviation of the drought-induced oxidative stress in RGS003. RGS003 cultivar exhibited significantly higher antioxidative enzymes activity at most levels of drought, which could lead to its drought tolerance and lower MDA content. In contrast to that of Sarigol, the activity of catalase and superoxide dismutase (SOD) increased with Ca and PEN/Ca treatments in RGS003 under low stress. The application of PEN and Ca induced significantly P5CS and SOD expression in RGS003 under drought stress after 24 h. Overall, these data demonstrated that PEN and Ca have the ability to enhance the tolerance against the drought stress in canola plants.

On the Question of the Chlorophyll a Content of the Photosystem II Reaction Center

1994 ◽  
Vol 98 (31) ◽  
pp. 7725-7735 ◽  
Author(s):  
H.-C. Chang ◽  
R. Jankowiak ◽  
N. R. S. Reddy ◽  
C. F. Yocum ◽  
R. Picorel ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Chlorophyll A ◽  
Reaction Center ◽  
Chlorophyll A Content

scholarly journals The Epiphytic FernElaphoglossum luridum(Fée) Christ. (Dryopteridaceae) from Central and South America: Morphological and Physiological Responses to Water Stress

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Bruno Degaspari Minardi ◽  
Ana Paula Lorenzen Voytena ◽  
Marisa Santos ◽  
Áurea Maria Randi
Keyword(s):  
Water Stress ◽  
Water Deficit ◽  
Chlorophyll A ◽  
Tca Cycle ◽  
Photosynthetic Parameters ◽  
Relative Water ◽  
Physiological Studies ◽  
Cycle Regulation ◽  
Epiphytic Fern ◽  
Chlorophyll A Content

Elaphoglossum luridum(Fée) Christ. (Dryopteridaceae) is an epiphytic fern of the Atlantic Forest (Brazil). Anatomical and physiological studies were conducted to understand how this plant responds to water stress. TheE. luridumfrond is coriaceus and succulent, presenting trichomes, relatively thick cuticle, and sinuous cell walls in both abaxial and adaxial epidermis. Three treatments were analyzed: control, water deficit, and abscisic acid (ABA). Physiological studies were conducted through analysis of relative water content (RWC), photosynthetic pigments, chlorophyll a fluorescence, and malate content. No changes in RWC were observed among treatments; however, significant decreases in chlorophyll a content and photosynthetic parameters, including optimal irradiance (Iopt) and maximum electron transport rate (ETRmax), were determined by rapid light curves (RLC). No evidence of crassulacean acid metabolism (CAM) pathway was observed inE. luridumin response to either water deficit or exogenous application of ABA. On the other hand, malate content decreased in theE. luridumfrond after ABA treatment, seeming to downregulate malate metabolism at night, possibly through tricarboxylic acid (TCA) cycle regulation.

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