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Title: Morpho-Anatomical and Physiological Modifications for Salinity Tolerance in Differently Adapted Ecotypes of Cyperus alopecuroides Rottb
Authors: Iqbal, Mustansar
Keywords: Biological & Medical Sciences
Issue Date: 2018
Publisher: University of Sargodha, Sargodha.
Abstract: Morpho-anatomical and Physiological modifications for salinity tolerance were investigated in seven populations (Ecotypes) of Cyperus alopecuroides Rottb. Plants collected from Jhang site, Qadir Abad site, Nankana site and Sheikhupura site of Punjab, Pakistan were grown in aquatic conditions. All seven populations were subjected to four levels (0 mM, 100 mM, 200 mM, and 300 mM) of NaCl salt stress in non-aerated solution culture. Experiment was conducted in completely randomized design. All ecotypes had high degree of salt tolerance, therefore well adapted to hypersaline wetlands and salt marshes. Response of each ecotypes was different to increasing salt stress that was based on specific morpho-anatomical and physiological parameters. But some ecotypes showed better growth rate as compared to others. They showed stability in chlorophyll content, increased in CO2 assimilation rate at moderate salinity levels, decrease transpiration rate, hence markedly increased water use efficiency under salinity stress, high stomatal conductance, increased N%, high Na+ and Cl uptake in roots along with increased K+ , and low translocation of toxic ions in shoot. Anatomically, increase in root endodermis thickness, aerenchyma, decrease in metaxylem area, decrease in leaf, stem and bract epidermal cell area, metaxylem, decrease in stomatal density were clear indicators of salt tolerance which prevent water loss. Moreover, increase in succulence, restricted uptake of toxic ions, and osmotic adjustment enhance markedly degree of salt tolerance in this species. Aerenchyma is a characteristics feature of this species, which mainly involved in gaseous exchange under anaerobic condition, but also reported to be in bulk movement of salts from roots to external environment. The differently adapted ecotypes were evaluated in controlled environments and therefore, only genetically fixed characters expressed relating to their adaptive components. These genetic variations in different populations may be supposed to be fixed due to high selection pressure of adverse saline environment in view of their evolutionary history. Key words: Morpho-anatomical, Salinity, Pigments, Metaxylem, Ecotypes, Cyperus alopecuroides Rottb. Aerenchyma, Sclerenchyma.
Gov't Doc #: 25036
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

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