تاثير پتانسيل آب و ماده ايجادكننده آن بر جوانه زني سه گياه زراعي گندم ، چغندرقند و نخود

Effects of water potential and type of Gsmoticum on seed germination of three crop species of wheat, sugarbeet, and chikpea

Crop seed germination and seedling growth are exposed to drought and salinity in some areas specially in arid and semi-arid regions and combined effect of these stresses on germination and emergence is ofʹ considerable interest. A growth chamber study was conducted to investigate seed germination of wheat (Triticum aestivurn), sugarbeet (Beta vulgaris) and chickpea (Cicer arietinum) in reduced water potential (distilled water as control, 0.32, 0.56, and 0.80 MPa). Negative potentials were simulated by using concentrated macronutrient solution (NPK), NaCl, CaC12 and polyethylene glycol (PEG-6000). Treatments were arranged in a completely randomised design using a 4*4*3 factorial experiment with four replications (4 levels of water potential, three species, and four types of osmoticum]. In each treatment 50 seeds were planted in a 11 cm diameter petri dish. Parameters examined in germinating seeds were rate of imbibition per day, rate and duration of emergence and elongation and weight of radicle and plumule. For all three species duration and rate of germination increased with increasing negative water potenital, but the sensitivity of species were quite different, wheat seeds were emerged fastest at all water potenitials and osmoticums, followed by chickpea and then sugarbeet. Although sugarbeet is a salt resistant cropʹits seed germination and dry matter build up in radicle and plumule reduced more than other two crops by water potential. Different osmoticums in the same water potential showed significant differences in rate and duration of germination as well as radicle and plumule length and weight particularly in sugarbeet and chickpea. At all three species concentrated macronutrient NPK showed better performance than others and PEG-6000 had the most inhibitory effect on seed germination. Differences between NaCl and CaCl2 generally became less pronounced. These results suggest that PEG-6000 may exert specific effect and concentrated NPK could be a suitable alternative for PEG.