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 (ECe 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 (ECe 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.
