Cultivar Specific Response of CO₂ Fertilization on Two Tropical Mung Bean (Vigna radiata L.) Cultivars: ROS Generation, Antioxidant Status, Physiology, Growth, Yield and Seed Quality

Abstract

Increasing atmospheric carbon dioxide concentration (CO2) is an important component of global climate change that will have a significant impact on the productivity of crop plants. In recent years, growth and yield of agricultural crop plants have been shown to increase with elevated CO2 (EC) and have enticed considerable interest due to variation in the response of crop plants. In this study, comparative response of two mung bean cultivars (HUM‐2 and HUM‐6) was evaluated against EC at different growth stages under near‐natural conditions for two consecutive years. The plants were grown in ambient as well as EC (700 ppm) in specially designed open‐top chambers. Under elevated CO2, marked down‐regulation of reactive oxygen species (ROS) levels, membrane disruption and activities of superoxide dismutase and catalase were noticed in both the cultivars, but the extent of reduction was more in HUM‐6. As compared to ambient CO2, EC increased total chlorophyll, photosynthetic rate, growth and yield parameters. Cultivar‐specific response was noticed as HUM‐6 showed higher increase in yield attributes than HUM‐2. Under CO2 treatment, soluble protein and reducing sugars decreased while total soluble sugars and starch showed an opposite trend. Principal component analysis showed that both the cultivars responded more or less similarly to EC in their respective groupings of physiological and growth parameters, but the magnitude of ROS and antioxidative enzymes was variable. The experimental findings depict that both the cultivars of mung bean showed contrasting response against EC and paved the way for selecting the suitable cultivar having higher productivity in a future high‐CO2 environment.

Response and adaptation of photosynthesis, respiration, and antioxidant systems to elevated CO2 with environmental stress in plants

“…Elevated CO 2 may increase the levels of antioxidants, including polyphenols, ascorbate (ASC), alkaloids, and some antioxidant enzyme activities (such as CAT and SOD), with a significant enhancement in the antioxidant capacity, leading to declines in the ROS levels ( Mishra and Agrawal, 2014 ; Zinta et al, 2014 ). For example, when the plants were exposed to elevated CO 2 , increases in the ASC and phenol levels were obtained in Beta vulgaris ( Kumari et al, 2013 ), and increases in the ASC, glutathione (GSH), and ASC/GSH, as well as in their redox status, were found in L. perenne and M. lupulina ( Farfan-Vignolo and Asard, 2012 ).…”

“…Moreover, with a delay in the onset of senescence and/or severe stress under elevated CO 2 conditions, it is suggested that the antioxidant profiles, such as the accumulation of antioxidant compounds and antioxidant enzyme activity, may show better performance in dealing with the biological process of senescence ( Hodges and Forney, 2000 ). For instance, a reduction in the oxidative stress under elevated CO 2 was found in Zingiber officinale ( Ghasemzadeh et al, 2010 ), Catharanthus roseus ( Singh and Agrawal, 2015 ), a temperate grassland shrub, Caragana microphylla ( Xu et al, 2014 ), a bean, Vigna radiate ( Mishra and Agrawal, 2014 ), and A. thaliana plants ( Zinta et al, 2014 ).…”

“…Base on a recent report ( Singh and Agrawal, 2015 ), the activities of the SOD, CAT, and APX declined, but the GR and POX were stimulated, finally leading to a significant reduction in the , H 2 O 2 , and malondialdehyde (MDA) contents in C. roseus plants grown under elevated CO 2 . Recently, marked decreases in the ROS levels ( , H 2 O 2 ) and reductions in some antioxidant enzymes, such as CAT and SOD, were observed simultaneously in mung bean plants exposed to elevated CO 2 , suggesting that a lower level of ROS might match the lower activity of antioxidant enzymes ( Mishra and Agrawal, 2014 ).…”

Impact of Abiotic Stresses on Grain Composition and Quality in Food Legumes

“…In mung bean, increased [CO 2 ] significantly reduced the percentages of palmitic and omega-6 fatty acids in mature grains, but increased omega-3 fatty acids and the relative proportion of omega-3 to omega-6 fatty acids(Table 6).63 Significant reduction in grain protein, by 1.4%, was noted in soybean at elevated [CO 2 ] 134. Under elevated [CO 2 ], soluble protein and reducing sugar contents declined while total soluble sugars and starch increased in mung bean 135.…”

Impacts of abiotic stresses on the physiology and metabolism of cool‐season grasses: A review

“…Apart from carbon metabolism, changes in CO 2 atmospheric levels have been reported to have a positive impact on plant defense mechanisms against oxidative damage by increasing antioxidant capacity (Mishra & Agrawal, ; Zinta et al., ). Farfan‐Vignolo and Asard () reported in perennial ryegrass exposed to elevated CO 2 concentrations that both pronounced increases and decreases were observed in the components of the ascorbate/glutathione cycle.…”