Effet du stress salin sur la germination des graines de deux especes cucurbitacees citrullus lanatus (thunb.)‎ Matsum & nakai et cucurbita pepo l

Abstract EN

The first purpose of this study is to determine the conditions that allow obtaining a better germination rates in a relatively short time in two species: Citrullus lanatus and Cucurbita pepo.

The germinating seeds in a peat/sand mixture (2/3, 1/3) enabled to obtain a germination rate of 0% in Cucurbita and 4.8% in watermelon.

Whereas, when the seeds are germinating in Petri dishes, on a filter paper soaked with water, the percentage of germination is 0% for Cucurbita and 57% for watermelon.

However when seeds coats are removed before setting germination, the percentage of germination increases to 100 % in Cucurbita.

The highest rate of germination is obtained where the seeds without coats are cultured in vitro in a sterile culture medium (8g/l agar).

The percentage of germination reached in this case 47.6% in Cucurbita and 100% in watermelon.

The plants obtained in vitro are a material of choice for micropropagation of different species of Cucurbitaceae.

The second aim of this study is to evaluate the effects of the salinity (sodium chloride) upon the capacity, the rate and the germination period of two Cucurbitaceae species, watermelon (Citrulus lanatus) and zucchini (Cucurbita pepo).

The seeds are irrigated with six NaCl solutions at different concentrations (0, 50, 100, 150, 200, and 400 mM).

Important differences are observed between the studied species for each criterion.

The result shows that the saline stress have a significant influence on the germination by decreasing the rate and the capacity.

The most important decrease is observed at the 200 and 400 mM concentrations mainly in the case of the watermelon.

However, the zucchini showes the highest tolerance to the saline stress with the lowest decrease percentage.