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Pak. J. Bot., 48(4): 1353-1360, 2016.

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SALT STRESS RESPONSES OF PIGEON PEA (CAJANUS CAJAN) ON GROWTH,

YIELD AND SOME BIOCHEMICAL ATTRIBUTES

TAYYAB^1,2*, MUHAMMAD AZEEM¹, MUHAMMAD QASIM³,

NAEEM AHMED¹ AND RAFIQ AHMAD¹

¹ Biosaline Research Laboratory, Department of Botany, University of Karachi, Karachi-75270, Pakistan

²Department of Botany, Government Islamia Science College Karachi, Karachi. Pakistan

³Institute of Sustainable Halophyte Utilization (ISHU), University of Karachi, Karachi-75270, Pakistan

*Corresponding author, email: tayyabhanif1@hotmail.com; Tel. +92321-2193971

Abstract

Growth responses of leguminous plants to salinity vary considerably among species. Pigeon pea (Cajanus cajan (L.) Millsp.) is a sub-tropical crop, grown worldwide particularly in South Asia for edible and fodder purposes, while little is known about its salinity tolerance. In order to investigate the effect of salinity, plants were established at six different levels of sea salt concentrations i.e. 0.5, 1.6, 2.8, 3.5, 3.8 and 4.3 (EC_e dS.m^-1). Plant growth was measured using vegetative [height, fresh and dry biomass, moisture, relative growth rate (RGR) and specific shoot length (SSL)], reproductive (number of flowers, pods, seeds and seed weight) and some biochemical parameters (chlorophylls, carotenoids, sugars and proteins). Pigeon pea showed a salt sensitive growth response, however, it survived up to 3.5 (EC_e dS.m^-1) sea salt salinity. Plant height, biomass, SSL and RGR linearly decreased under saline conditions. Leaf pigments increased (chlorophylls) or maintained (carotenoids) at 1.6 dS.m^-1 and subsequently decreased in higher salinity. Low moisture content and succulence along with more accumulation of soluble sugars and proteins may be attributed to leaf osmotic adjustments at low salinity. Salinity adversely affect reproductive growth of C. cajan where production of flowers, pods, number of seeds and seed weight were significantly reduced. Present study provides basic information related to plant growth, seed yield and some biochemical attributes, which suggest C. cajan as a salt sensitive leguminous crop. However, detailed information is required to understand the eco-physiological responses of this plant under field and green house conditions.

Keywords: Edible, Fodder, Marginal lands, Saline agriculture, Salt tolerance.