Effect of freezing stress on viola (Viola gracilis L.) under laboratory conditions

Document Type : Scientific - Research

Authors

Ahmad Nezami

Fatemeh Keykha Akhar

Mohammad Javad Mousavi

Ebrahim Izadi

Somayeh Nezami

Maryam Yousef Sani

Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran

10.22067/jag.v3i4.13571

Abstract

In order to evaluation of freezing tolerance in viola (Viola gracilis L.) under controlled conditions, a trial carried out in completely randomized design with six replications at college of agriculture, Ferdowsi University of Mashhad, Iran, during 2008-2009. Seeds were planted in bed and seedlings were acclimated during natural conditions in autumn and at 5-7 leaves stage plants transferred to the thermo-gradient freezer to apply 12 freezing temperatures (0, -2, -4, -6, -8, -10, -12, -14, -16, -18, -20 and -22°C). Leaf cell’s membrane integrity was measured through electrolyte leakage (EL) after the freezing and survival percentage and plant recovery (e.g. plant height and dry weight, number of branches and flowers and flower’s diameter) were determined after three weeks of plant re-growth in the cold frame. As temperature decreased, EL% increased significantly and reached to the maximum in -20oC. Survival percentage did not affected by temperatures between 0oC to -18oC but all plants killed in -22oC. LT50el and LT50su were -20.0°C and -19.4°C, respectively. Decreasing the temperature lower than -18 oC reduced plant dry matter severely and RDMT50 was -19.2°C.

Keywords

Cold acclimation

Dry matter

Electrolyte leakage

Survival percentage

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