title: Changes in hydraulic conductance cause the difference in growth response to short-term salt stress between salt-tolerant and -sensitive black gram (Vigna mungo) varieties.
abstract: Black gram (Vigna mungo) is an important crop in Asia, However, most black gram varieties are salt-sensitive. The causes of varietal differences in salt-induced growth reduction between two black gram varieties, 'U-Taung-2' (salt-tolerant; BT) and 'Mut Pe Khaing To' (salt-sensitive; BS), were examined the potential for the first step toward the genetic improvement of salt tolerance. Seedlings grown in vermiculite irrigated with full-strength Hoagland solution were treated with 0mM NaCl (control) or 225 mM NaCl for up to 10 days. In the 225 mM NaCl treatment, plant growth rate, net assimilation rate, mean leaf area, leaf water potential, and leaf photosynthesis were reduced more in BS than in BT plants. Leaf water potential was closely related to leaf photosynthesis, net assimilation rate, and increase in leaf area. In response to salinity stress, hydraulic conductance of the root, stem, and petiole decreased more strongly in BS than in BT plants. The reduction in stem and petiole hydraulic conductance was caused by cavitation, whereas the reduction in root hydraulic conductance in BS plants was caused by a reduction in root surface area and hydraulic conductivity. We conclude that the different reduction in hydraulic conductance is a cause of the differences in the growth response between the two black gram varieties under short-term salt stress.
authors.affiliation: Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan. Electronic address: khinthuzarwin@gmail.com.
authors.forename: Khin Thuzar
authors.initials: KT
authors.lastname: Win
authors.affiliation: Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Aung Zaw
authors.initials: AZ
authors.lastname: Oo
authors.affiliation: Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Taiichiro
authors.initials: T
authors.lastname: Ookawa
authors.affiliation: Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Kanekatsu
authors.affiliation: Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Saiwaicho 3-5-8, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Tadashii
authors.initials: T
authors.lastname: Hirasawa
mesh_terms: D000818:Animals; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000502:physiology; D018547:Plant Stems / Q000187:drug effects / Q000502:physiology; D018526:Plant Transpiration / Q000187:drug effects*; D054712:Salinity; D055049:Salt Tolerance; D012965:Sodium Chloride / Q000494:pharmacology*; D013997:Time Factors; D000070658:Vigna / Q000187:drug effects / Q000502:physiology*; D014867:Water / Q000502:physiology
chemical_list: D014867:Water; D012965:Sodium Chloride
keywords: Black gram; Cavitation; Hydraulic conductance; Photosynthesis; Salt stress; Water potential