Effect of Vermicompost on Membrane Lipid Peroxidation and some Morphophysiological Characteristics of Fennel (Foeniculum vulgare Mill.) Landraces under Salt Stress

In order to investigate the interaction effect of vermicompost and sodium chloride on some characteristics of fennel as a medicinal plant, a factorial experiment was conducted in a randomized complete block design in the greenhouse conditions. Experimental treatments consisted of four levels of salinity (0, 40, 80 and 120mM sodium chloride) and two levels of vermicompost (0 and 5% volumetric), which were applied to four fennel landraces of Urmia, Shiraz, Bushehr and Mashhad. Plants were harvested five weeks after planting and then some of their traits were measured. According to the results of this experiment, vermicompost application induced a significant increase in the dry weight of shoot, chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, magnesium, iron, phosphate, nitrate, membrane stability index, relative water content, and a decrease in the malondialdehyde and other aldehydes of shoot in most studied fennel landraces. In contrast, under salt stress condition (without vermicompost), reverse results were obtained. The highest and the lowest effects of 120 mM sodium chloride on shoot dry weight in the studied fennel landraces were observed in Mashhad (more than two fold) and Shiraz (about 58 percent) landraces, respectively. Nevertheless, the results of interaction between vermicompost and salinity showed that dry weight of shoot, photosynthetic pigments, mineral elements, membrane stability index and relative water content of fennel were significantly increased in the presence of some salinity levels under vermicompost treatment. Malondialdehyde and other aldehydes were also reduced in these conditions. Under combined application of vermicompost and 120 mM sodium chloride, shoot dry weight of Shiraz landrace was increased more than two fold, the highest increase of this trait among the fennel landraces.