Salt-induced modulation in some key gas exchange characteristics and ionic relations in pea (Pisum sativum L.) and their use as selection criteria

A glasshouse experiment was conducted to assess the influence of salt stress on some key physiological attributes of nine genetically diverse cultivars of a potential vegetable crop, pea (Pisum sativum L.). The nine pea cultivars (2001-20, 2001-35, 2001-40, 2001-55, 9800-5, 9800-10, 9200, Tere-2 and Climax) were exposed to four levels (0, 40, 80, and 120mM) of NaCl in sand culture. Salt stress reduced the shoot and root dry weights, chlorophyll concentration, gas exchange and water relation parameters, leaf and root K, Ca and K: Na ratio, while it enhanced concentrations of proline, leaf and root Na and Cl contents. Of all cultivars, 9800-10, 2001-20, 2001-55 and 2001-35 were higher in plant dry biomass, chlorophyll concentrations as well as in photosynthetic rate than the other cultivars at the highest salt regime whereas cvv. 2001-40, 9800-5 and 9200 were the lowest in these attributes. Overall, the genetically diverse cultivars of pea showed varying degree of salt tolerance. As the expression of different biochemical and physiological attributes differed in different cultivars under saline conditions, most of the attributes could be used as selection criteria for salt tolerance of pea. Thus, chlorophyll a, b and photosynthetic rate have great practical importance as effective physiological selection criteria for the selection of salt-tolerant pea cultivars.