Rahima Khatoon; Md. Mokter Hossain; Limu Akter
Abstract
Sweet gourd (Cucurbita moschata Duch ex Poir) has a high production volume in Bangladesh and holds third rank next to eggplant and radish. Salinity affects almost all growth and physiological aspects of the plant development and eventually reduces yield. Identifying salt tolerance among genetic resources ...
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Sweet gourd (Cucurbita moschata Duch ex Poir) has a high production volume in Bangladesh and holds third rank next to eggplant and radish. Salinity affects almost all growth and physiological aspects of the plant development and eventually reduces yield. Identifying salt tolerance among genetic resources and breeding populations is a valuable study for solving salinity problems. This research aimed to find sweet gourd hybrids tolerant to salinity. Sixteen sweet gourd hybrids (F1) were used for testing salt stress tolerance levels. Salinity stress was induced in pot soil by adding NaCl solutions (4, 8, 12, 16, and control 0.35 dS m-1). The experiment was conducted from October 2019 to March 2020 in a randomized complete block design with three replications. The research was conducted at the Horticulture Research Centre, Bangladesh Agricultural Research Institute (BARI), Gazipur. The measurements included changes in gas exchange parameters against photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (E), quantum yield (Fv/Fm), and relative water content (RWC). Results showed that the gas exchange traits and RWC in all hybrids decreased under stress compared to the control. Photosynthetic parameters in sweet gourd hybrids responded susceptibly to salt stress, thus suppressing overall growth under salinity stress. The reduction of gaseous exchange traits and RWC were minimal in P11 × P12 and P6 × P14. The highest Fv/Fm and RWC occurred in P11 × P12 at 8 dS m-1 salinity stress. The highest Fv/Fm and RWC appeared in P6 × P14 and P11 × P12 hybrids at 12 and 16 dS m-1 salinity stress, so the hybrid P11 × P12 appeared salt tolerant.
Fariba Bagheri; Abdolhosein Rezaei Nejad; Mohammad Reza Raji
Abstract
Waterlogging may be imposed by intense rainfall, excessive irrigation, or poor drainage. In Iran, besides the northern parts of the country with high precipitation, waterlogging may occur due to over-irrigation, or inadequate drainage especially for landscape use of ornamentals. In this study, the joint ...
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Waterlogging may be imposed by intense rainfall, excessive irrigation, or poor drainage. In Iran, besides the northern parts of the country with high precipitation, waterlogging may occur due to over-irrigation, or inadequate drainage especially for landscape use of ornamentals. In this study, the joint effects of growth stage (four-leaf stage, full growth and start flowering), at which waterlogging is encountered, and the duration of the episode (0, 6, 12, and 24 h) on flowering induction, plant growth, and external quality were investigated in zinnia (Zinnia elegans Jacq.). Waterlogging generally downgraded visually-perceived quality (stem length, flower size, leaf coloration), increased the risk of buckling (lower stem strength) and shortened flower bud longevity. Waterlogging adversely affected biomass accumulation, through decreases in both light capture (leaf area), and photosynthesis. Besides disturbed water relations, waterlogged plants underwent oxidative damage as indicated by reduced chlorophyll content, and elevated lipid peroxidation level. Waterlogging was further associated with increased activity of antioxidant enzymes (ascorbate peroxidase, peroxidase). The waterlogging-induced effects were generally more prominent as waterlogging duration increased, and the growth stage of application was less advanced, so that the plants waterlogged in four-leaf stage for 24 h showed the most negative effects and their plant dry weight reduced to 75 percent of that in controls. In conclusion, the obtained results offer a quantitative analysis of how both growth stage and duration determine the waterlogging-induced injury in zinnia.
