Germination and seedling growth of hory cress (Cardaria draba L.) and madwort (Alyssum hirsutum L.) weeds to salinity and drought stress

Weed in terms of the growth and the type of damage that cause and respond to different methods are different, you must first growth behaviors and response to environmental factors, the identification of various weed and then depending on the nature and behavior them the planning to manage the different species. One of the most important factors for successful weed seed germination that various environmental factors such as light, temperature, humidity, soil pH, salinity and drought stress is important, Response weeds varies is considerably in this respect. The competition started a weed that can be effective at an ecological niche. For being a weed able to compete for ecological niche germination is important.  

In order to assess the tolerance of this weed germination and seedling growth of weeds (Cardaria draba) and alyssum (Alyssum Hirsutum) ecotype Karaj to salinity and drought stress two separate trials in a completely randomized design with six treatments and four replications for each weed in weed Research Laboratory Bu-Ali Sina University Hamedan was conducted in 2015. On drought stress by solving a certain amount of polyethylene glycol 6000 for potential (-2, -4, -6, -8 and -10 Bar)  and Salinity by dissolving different amounts of sodium chloride in distilled water to create potential (-2, -4, -6, -8 and -10 Bar) and distilled water for each two experiments were used for without stress conditions. Seed disinfected with sodium hypochlorite (5%) for 2 minutes and then rinse with distilled water for 3 minutes, 25 seed inside diameter of 9 cm plate with two layers of filter paper were placed on the amount of 5 ml of distilled water or solvent with drought and salinity levels that were added to it. At the end of experiment characteristics of such as germination percentage, speed germination, seedling vigor index, seedling radicle and hypocotyl Length and weight were measured treatments.

The results showed that the drought and salinity from zero to -10 Bar decreased significantly (p<0.05) the percentage of germination, seedling vigor index, radicle and hypocotyl length, fresh and dry weight of seedling weeds. With increasing intensity of drought stress from zero to -10 Bar hoary cress and madwort seed germination was reduced 12 and 67 percent respectively compared to control. Madwort weed seed germination under drought stress was more than hoary cress plant. By capture both weed seed germination under salt stress and drought decreased madwort weed in germination was slow. Increased drought stress resulted in reduced seedling vigor in this weed. Highest (3.47) and the lowest (1.30) seedling vigor was observed at the controlled conditions and -6 Bar potential respectively and with increased the drought stress, there was no significant difference. Due to the loss of madwort weed seedlings at the above potential of -4 bars was not possible to measure seedling vigor. The salt stress caused to significant reduction in hoary cress and madwort seedling vigor. This index is a function of the germination percentage and seedling length and the fact that the stress seedling vanished, so the trait was not calculated. With increasing intensity of drought stress, the radicle and hypocotyl weight response in this weed was similar to alyssum. More decreased with increasing drought stress was observed in hory cress radicle. Highest hypocotyl and radicle growth in madwort weed was observed in control and drought stress had stopped growth radicle and hypocotyl seedling to stress and the destroyed after 15 days. According to the results seems to the germinated seeds of hory cress and madwort are highly sensitive to salinity and drought. However, the sensitivity to salt stress was higher the than drought stress in both weed. By comparing the two results show that madwort weed to drought and salinity stress this weed is more sensitive to stress as the minimum amount (-2 Bar) seedling growth processes were stopped.