scholarly journals Effects of Elevated Temperature and Ozone in Brassica juncea L.: Growth, Physiology, and ROS Accumulation

Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 68 ◽  
Author(s):  
Jong Kyu Lee ◽  
Su Young Woo ◽  
Myeong Ja Kwak ◽  
Sang Hee Park ◽  
Han Dong Kim ◽  
...  

Global warming and ozone (O3) pose serious threats to crop yield and ecosystem health. Although neither of these factors will act individually in reality, most studies have focused on the responses of plants to air pollution or climate change. Interactive effects of these remain poorly studied. Therefore, this study was conducted to assess the effects of optimal (22/20 °C day/night) and elevated temperature (27/25 °C) and/or ambient (10 ± 10 nL L−1) and elevated O3 concentrations (100 ± 10 nL L−1) on the growth, physiology, and reactive oxygen species (ROS) accumulation of leaf mustard (Brassica juncea L.). The aim was to examine whether elevated temperature increase the O3 damage due to increasing stomatal conductance, and thus, O3 flux into the leaf. Significant reductions in photosynthetic rates occurred under O (elevated O3 with optimal temperatures) and OT (elevated O3 and temperature) conditions compared to C (controls). Stomatal conductance was significantly higher under T than in the C at 7 DAE. Under OT conditions, O3 flux significantly increased compared to that in O conditions at 7 days after exposure (DAE). Significant reductions in total fresh and dry weight were observed under OT conditions compared to those under O. Furthermore, significant reductions in levels of carotenoids and ascorbic acid were observed under OT conditions compared to O. Lipid peroxidation and accumulation of ROS such as hydroxyl radical, hydrogen peroxide, and superoxide radical were higher under O and OT conditions than in C conditions at 7 and 14 DAE. As a result of O3 stress, the results of the present study indicated that the plant injury index significantly increased under OT compared to O conditions. This result suggested that elevated temperature (+5 °C) may enhance O3 damage to B. juncea by increasing stomatal conductance and O3 flux into leaves.

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 357
Author(s):  
Jong Kyu Lee ◽  
Myeong Ja Kwak ◽  
Sang Hee Park ◽  
Han Dong Kim ◽  
Yea Ji Lim ◽  
...  

Plants are affected by the features of their surrounding environment, such as climate change and air pollution caused by anthropogenic activities. In particular, agricultural production is highly sensitive to environmental characteristics. Since no environmental factor is independent, the interactive effects of these factors on plants are essential for agricultural production. In this context, the interactive effects of ozone (O3) and supraoptimal temperatures remain unclear. Here, we investigated the physiological and stomatal characteristics of leaf mustard (Brassica juncea L.) in the presence of charcoal-filtered (target concentration, 10 ppb) and elevated (target concentration, 120 ppb) O3 concentrations and/or optimal (22/20 °C day/night) and supraoptimal temperatures (27/25 °C). Regarding physiological characteristics, the maximum rate of electron transport and triose phosphate use significantly decreased in the presence of elevated O3 at a supraoptimal temperature (OT conditions) compared with those in the presence of elevated O3 at an optimal temperature (O conditions). Total chlorophyll content was also significantly affected by supraoptimal temperature and elevated O3. The chlorophyll a/b ratio significantly reduced under OT conditions compared to C condition at 7 days after the beginning of exposure (DAE). Regarding stomatal characteristics, there was no significant difference in stomatal pore area between O and OT conditions, but stomatal density under OT conditions was significantly increased compared with that under O conditions. At 14 DAE, the levels of superoxide (O2-), which is a reactive oxygen species, were significantly increased under OT conditions compared with those under O conditions. Furthermore, leaf weight was significantly reduced under OT conditions compared with that under O conditions. Collectively, these results indicate that temperature is a key driver of the O3 response of B. juncea via changes in leaf physiological and stomatal characteristics.


2019 ◽  
Vol 39 (11) ◽  
pp. 1806-1820 ◽  
Author(s):  
Deborah M G Apgaua ◽  
David Y P Tng ◽  
Samantha J Forbes ◽  
Yoko F Ishida ◽  
Nara O Vogado ◽  
...  

Abstract Climate change scenarios predict increasing atmospheric CO2 concentrations ([CO2]), temperatures and droughts in tropical regions. Individually, the effects of these climate factors on plants are well established, whereas experiments on the interactive effects of a combination of factors are rare. Moreover, how these environmental factors will affect tree species along a wet to dry gradient (e.g., along tropical forest–savanna transitions) remains to be investigated. We hypothesized that under the simulated environmental conditions, plant growth, physiological performance and survivorship would vary in a manner consistent with the species’ positions of origin along this gradient. In a glasshouse experiment, we raised seedlings of three Eucalyptus species, each occurring naturally in a wet forest, savanna and forest–savanna ecotone, respectively. We evaluated the effect of drought, elevated temperature (4 °C above ambient glasshouse temperature of 22 °C) and elevated temperature in combination with elevated [CO2] (400 ppm [CO2] above ambient of 400 ppm), on seedling growth, survivorship and physiological responses (photosynthesis, stomatal conductance and water-use efficiency). Elevated temperature under ambient [CO2] had little effect on growth, biomass and plant performance of well-watered seedlings, but hastened mortality in drought-affected seedlings, affecting the forest and ecotone more strongly than the savanna species. In contrast, elevated [CO2] in combination with elevated temperatures delayed the appearance of drought stress symptoms and enhanced survivorship in drought-affected seedlings, with the savanna species surviving the longest, followed by the ecotone and forest species. Elevated [CO2] in combination with elevated temperatures also enhanced growth and biomass and photosynthesis in well-watered seedlings of all species, but modified shoot:root biomass partitioning and stomatal conductance differentially across species. Our study highlights the need for a better understand of the interactive effects of elevated [CO2], temperature and drought on plants and the potential to upscale these insights for understanding biome changes.


2005 ◽  
Vol 86 (1) ◽  
pp. 7-17
Author(s):  
Catherine Gaucher ◽  
Pierre Dizengremel ◽  
Yves Mauffette ◽  
Normand Chevrier

The effects of three times ambient [O3] (3x) and high [CO2] (650 µL L-1 CO2) alone and in combination were studied on 2-yr-old sugar maple (Acer saccharum) seedlings for 86 days in open top chambers. Sugar maple net CO2 assimilation rate and growth were not decreased by the O3 treatment after one growing season, and the epicuticular wax was not damaged compared with the control. The absence of response to the O3 treatment is attributable to the low stomatal conductance of this species resulting in a low O3 uptake, together with the succession of periods of high and low [O3], which allowed the seedlings to alleviate the oxidative stress. At the end of August, under high [CO2], the growth of the seedlings and net CO2 assimilation to stomatal conductance to CO2 ratio in the second flush of leaves had doubled. Under the environmental growth conditions of the chambers (high light, nutrients and water availabilities), the seedlings may benefit from the availability of CO2. Sugar maple seedlings may have a competitive growth advantage under elevated CO2 conditions and three times ambient [O3] did not decreased the fertilizing effect of CO2.


2018 ◽  
pp. 310-316 ◽  
Author(s):  
Hassan Zeb ◽  
Azhar Hussain ◽  
Muhammad Naveed ◽  
Allah Ditta ◽  
Shakeel Ahmad ◽  
...  

Zinc (Zn) is an essential element for humans, animals and plants, however, its deficiency has been widely reported around the world especially in flooded rice. Adequate amount of Zn is considered essential for optimum growth and development of rice. We hypothesised that management practices like Zn-mineral fertiliser, -compost, and -solubilising bacteria would improve Zn availability and uptake in flooded rice. A series of studies were conducted to find out the comparative efficacy of Zn-enriched composts (Zn-ECs) with Zn solubilising bacteria (ZnSB) vs. ZnSO4 for improved growth, yield and Zn accumulation in rice. There were six treatments viz. control, ZnSB, ZnO (80% Zn), ZnSO4 (33% Zn), Zn-EC80:20 and Zn-EC60:40. In all the treatments, Zn was applied at the rate of 5 kg ha–1 except the control. The treatment Zn-EC60:40 resulted in the maximum Zn release in soil as compared to ZnSO4 and all other treatments during incubation study. The treatment Zn-EC60:40 significantly improved root dry weight, grain yield and 100-grain weight of rice by 15, 22 and 28%, respectively as compared to ZnSO4. The same treatment resulted in the maximum increase in photosynthetic rate (11%), transpiration rate (21%), stomatal conductance (17%), chlorophyll contents (8%) and carbonic anhydrase activity (10%) while a decrease of 27% in electrolyte leakage was observed in comparison with ZnSO4 application. Moreover, the maximum increase in grain quality parameters and Zn bioaccumulation was observed with the application of Zn-EC60:40 in comparison with ZnSO4 application and all other treatments. We conclude that Zn-EC60:40 are not only an effective strategy to improve growth, physiology and yield parameters of rice, but also to improve the grain quality and Zn-bioaccumulation in rice compared to ZnSO4.


Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 280-284 ◽  
Author(s):  
Kriton K. Hatzios

In greenhouse studies, the potential interactive effects of metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] treatments combined with the air pollutant ozone (O3) or the antioxidants, piperonyl butoxide {α-[2-butoxyethyl) ethoxy]-4,5-dimethylenedioxy-2-propyltoluene} andn-propyl gallate, on the growth of sorghum [Sorghum bicolor(L.) Moench ‘Funk G522DR’] seedlings that were protected or unprotected with the antidote, CGA-43089 [α-(cyanomethoximino)-benzacetonitrile], were examined. Metolachlor was applied preplant incorporated at rates of 2.2, 3.9, and 5.6 kg/ha, and it was evaluated against fumigation with O3at 0.2 and 0.3 ppmv or against 4.9, 6.7, and 9.0 kg/ha of each antioxidant applied preplant incorporated. In combination treatments, shoot dry weight at 30 days after planting was reduced more than expected by metolachlor in the presence of the protectant CGA-43089 and ozone or some rates of the two antioxidants, suggesting synergism. In the absence of the protectant, CGA-43089, growth responses of sorghum to combination treatments of metolachlor with ozone or propyl gallate suggested an additive effect, although some treatments of metolachlor combined with piperonyl butoxide interacted synergistically.


Forests ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 82 ◽  
Author(s):  
Yasutomo Hoshika ◽  
Elisa Carrari ◽  
Barbara Mariotti ◽  
Sofia Martini ◽  
Alessandra De Marco ◽  
...  

This study investigated visible foliar ozone (O3) injury in three deciduous tree species with different growth patterns (indeterminate, Alnus glutinosa (L.) Gaertn.; intermediate, Sorbus aucuparia L.; and determinate, Vaccinium myrtillus L.) from May to August 2018. Ozone effects on the timing of injury onset and a plant injury index (PII) were investigated using two O3 indices, i.e., AOT40 (accumulative O3 exposure over 40 ppb during daylight hours) and PODY (phytotoxic O3 dose above a flux threshold of Y nmol m−2 s−1). A new parameterization for PODY estimation was developed for each species. Measurements were carried out in an O3 free-air controlled exposure (FACE) experiment with three levels of O3 treatment (ambient, AA; 1.5 × AA; and 2.0 × AA). Injury onset was found in May at 2.0 × AA in all three species and the timing of the onset was determined by the amount of stomatal O3 uptake. It required 4.0 mmol m−2 POD0 and 5.5 to 9.0 ppm·h AOT40. As a result, A. glutinosa with high stomatal conductance (gs) showed the earliest emergence of O3 visible injury among the three species. After the onset, O3 visible injury expanded to the plant level as confirmed by increased PII values. In A. glutinosa with indeterminate growth pattern, a new leaf formation alleviated the expansion of O3 visible injury at the plant level. V. myrtillus showed a dramatic increase of PII from June to July due to higher sensitivity to O3 in its flowering and fruiting stage. Ozone impacts on PII were better explained by the flux-based index, PODY, as compared with the exposure-based index, AOT40. The critical levels (CLs) corresponding to PII = 5 were 8.1 mmol m−2 POD7 in A. glutinosa, 22 mmol m−2 POD0 in S. aucuparia, and 5.8 mmol m−2 POD1 in V. myrtillus. The results highlight that the CLs for PII are species-specific. Establishing species-specific O3 flux-effect relationships should be key for a quantitative O3 risk assessment.


Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 904 ◽  
Author(s):  
Zhong-Wei Zhang ◽  
Yi-Ying Dong ◽  
Ling-Yang Feng ◽  
Zong-Lin Deng ◽  
Qiang Xu ◽  
...  

Oilseed rape (Brassica napus) is a Cadmium (Cd) hyperaccumulator. However, high-level Cd at the early seedling stage seriously arrests the growth of rape, which limits its applications. Brassica juncea had higher Cd accumulation capacity, but its biomass was lower, also limiting its applications. Previous studies have confirmed that Selenium (Se) can alleviate Cd toxicity. However, the regulatory mechanism of Se in different valence states of Cd accumulation was unclear. In this study, we investigated the ameliorating effects of three Se valence states, Na2SeO4 [Se(VI)], Na2SeO3 [Se(IV)] and Se-Met [Se(II)], to Cd toxicity by physiological and biochemical approaches in hydroponically-cultured Brassica juncea and Brassica napus seedlings. Although Se treatments slightly inhibited seedling Cd concentration, it tripled or quadrupled the Cd accumulation level per plant, because dry weight increased about four times more with Se and Cd application than with Cd treatment alone. Among the different valence states of Se, Se(II) had the most marked effect on reducing Cd toxicity as evidenced by decreased growth inhibition and Cd content. The application of Se(II) was effective in reducing Cd-induced reactive oxygen species accumulation, and promoted the antioxidant enzyme activity and photosynthesis of both Brassica species. In addition, Se(II) treatment increased the concentrations of Cd in the cell wall and soluble fractions, but the Cd concentration in the organelle part was reduced.


FLORESTA ◽  
2011 ◽  
Vol 41 (3) ◽  
Author(s):  
Larissa De Bortollo Chiamolera ◽  
Alessandro Camargo Ângelo ◽  
Maria Regina Boeger ◽  
Fernando Correia Araújo

O objetivo deste trabalho foi verificar a influência de diferentes condições de luminosidade presentes em folhas de Mimosa scabrella Benthan plantadas em áreas com diferentes graus de sucessão nas margens do Reservatório Iraí, PR. Foram avaliados aspectos morfológicos (área foliar, peso seco, área foliar específica), anatômicos (espessuras de cutícula, epiderme adaxial, parênquima paliçádico, parênquima lacunoso, epiderme adaxial e espessura total), fisiológicos (taxa de fotossíntese, condutância estomática e transpiração) e desenvolvimento das plantas (altura, diâmetro e sobrevivência até os 18 meses). Para os parâmetros morfológicos, M. scabrella apresentou diferença significativa para a área foliar específica, que foi maior para os indivíduos da capoeira. Diferenças significativas foram encontradas para a espessura da epiderme adaxial e do parênquima paliçádico. A epiderme adaxial foi maior na área de capoeira, enquanto que o parênquima paliçádico maior na área aberta. Indivíduos da área aberta apresentaram maior taxa de transpiração e condutância estomática. Tanto a altura quanto o diâmetro não mostraram diferença significativa entre as áreas. A sobrevivência foi considerada insatisfatória para ambas as áreas, porém foi ligeiramente maior na capoeira. Esses resultados, aliados ao comportamento natural da espécie, sugerem que M. scabrella deve ser implantada em densidades maiores.Palavras-chave:  Morfoanatomia foliar; fisiologia, variação de luz; recuperação de área degradada; silvicultura de espécies nativas. AbstractAnatomical and physiological features of Mimosa scabrella leaves growing on areas with different succession stages This study aims to evaluate the influence of light conditions at different stages of succession in leaves of Mimosa scabrella Benthan planted in Iraí’s water reservoir margins, State of Paraná, Brazil. We evaluated leaf morphology (area, dry weight, specific area), anatomy (cuticle thickness, adaxial epidermis, palisade parenchyma, parenchyma spongy, adaxial epidermis and total thickness), physiology (photosynthesis rate, stomatal conductance, transpiration) and plant growth (height, diameter) and survival up to age of 18 months. Plants of Mimosa scabrella of natural regeneration showed greater leaf specific area than those of planted individuals. Significant differences were found on thickness of the adaxial epidermis and palisade parenchyma. The adaxial epidermis was higher in regenerating area, whereas the palisade parenchyma was higher in open field. Plants of open field presented higher values of transpiration and stomatal conductance. Concerning height and diameter growth, plants of both areas showed no significant differences. Survival was considered unsatisfactory for both areas, but was slightly higher in regenerating area. According to M. scabrella behavior in natural conditions, the results suggest that this species must be implanted in greater densities.Keywords:              Leaf morphology; leaf anatomy; physiology; light; land recuperation; native tree species.


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