RESUMO
Tropospheric ozone (O3) is a pervasive greenhouse gas and air pollutant known for its detrimental effects on human health and vegetation. In the recent years, tropospheric ozone has been rising steadily on the account of rapid urbanization and globalization. Hence, a study to investigate the impact of elevated ozone levels on cabbage cultivars have been initiated. The cultivars Tekila and Primero, which are extensively grown in the high-altitude region of the Western Ghats, India were used as test crop, where ozone levels are a growing concern. The study employed a comprehensive experimental design, encompassing ozone stress (200 ppb), cabbage varieties (Tekila and Primero), and different growth stages of the cabbage plants. Ozone fumigation at 200 ppb was used to simulate elevated ozone conditions, reflecting potential future scenarios. To assess the extent of impact both physiological and biochemical parameters were extensively analyzed. The results revealed that elevated ozone concentrations had a significant negative impact on both cabbage cultivars. Photosynthetic rate, stomatal conductance, and chlorophyll content declined progressively as ozone exposure continued, leading to maximum reductions of 71.2, 81.03 and 32.98% respectively. However, protective mechanisms were activated in response to ozone stress, including increased proline by 32.24%, ascorbic acid by 64.75%, catalase by 3.58%, and peroxidase activities by 56%, suggesting the cabbage plants' efforts to mitigate oxidative damage. Overall, this study highlights the vulnerability of cabbage cultivars to elevated ozone levels and emphasizes the need for effective mitigation strategies to safeguard crop productivity and ensure sustainable agriculture in regions facing escalating ozone pollution. Further research is essential to develop and implement solutions that can protect vital crops like cabbage from the adverse effects of tropospheric ozone.
RESUMO
Rapid and precise identification of three sex types (male, hermaphrodite and female flowers) is the key in achieving good returns in papaya (Carica papaya L.) cultivation. This study presents a simple, reliable, fast and cost-efficient DNA isolation protocol and a rapid and precise method of sex determination in papaya. Three DNA isolation protocols viz., CTAB method, Modified Dellaporta method and BioBasic DNA isolation kit were comparatively evaluated for their simplicity, economic, DNA quantity and purity. Among them, CTAB method was regarded as relatively economic, with a cost of Rs. 11.80943 per sample with higher amount of DNA (4667.4 µg/ µl). However, it was noticed that DNA isolation with the BioBasic kit was fastest method, which took only 6 hours 7 minutes. On the other hand, relatively better DNA purity was noticed with the Modified Dellaporta method (average ratio of absorbance at 260 nm and 280 nm range between 1.8-2.0) and yielded clear, intact and distinct DNA bands. Hence, Modified Dellaporta method is suggested as an ideal DNA isolation protocol for papaya. Molecular markers (such as SCAR derived from RAPD T12, W11, NAPF-2 and PKBT-4) were employed in this study to identify the sex type and they have successfully distinguished between male and hermaphrodite plants in both dioecious and gynodioecious varieties; especially, NAPF-2 has successfully distinguished male in dioecious varieties. Evaluation of different kinds of molecular markers has shown that the SCAR marker T12 can be used as reliable marker for rapid and precise identification of papaya sex type.