Allelopathic Effects of Weed Extracts on

Germination of some Vegetable Seeds (in Vitro)

[57]

Abdallah, M.M.F¹.; Z.S. Lasheene¹; H.M. Gomaa¹ and N.A.I. Abu-ElAzm¹

ABSTRACT

Filtered water extract of dried shoots of common lambsquarters (Chenopodium album), cocklebur (Xanthium stramarium) and purple nutsedge (Cyperus rotundus) were tested for their potential allelopathic effect on seed germination and seedling growth  of  onion, carrot, cabbage, watermelon, eggplant, and Jew’s mallow. The undiluted extracts (at 1% level) significantly reduced seed germination percentages by 25% in onion,  7%  in  carrot, 9%  in  cabbage,  14 % in eggplant and 20% in watermelon as an average of both experiments. Germination percentage of Jew’s mallow seed was not significantly affected by weed extracts. The undiluted and the one-tenth   diluted   extracts  (1% and 0.1% level) significantly   delayed   seed   germination of all studied   vegetable   crops.   The   effects   on   vegetable seed germination percentage and rate were not only affected by extracting concentration but also by weed species and their interactions. However, the effect on germination percentage was more pronounced at the higher extract concentration of common lambsquarters and the effect on seedling growth depended on the extract source and extract concentration. The hypocotyl length was inhibited (33% onion, 26% carrot, 29% cabbage 54% eggplant, 28% watermelon and 22% Jew’s mallow) compared to the undiluted extracts. The root length of studied vegetable seedlings was inhibited by the undiluted and ten-fold diluted extracts, but was stimulated by 8% at (0.001%) diluted level in watermelon seedling. Seedling fresh weight was also inhibited by all undiluted  extracts  and  by  ten-fold  dilution in some vegetables, i.e., onion and watermelon. Inhibition of vegetable seedling growth by extracts from nutsedge was lower than that caused by cocklebur and lambsquarters weeds.  The strong inhibitory effect by extract from the studied common weeds suggested that weed tissue may contain water- soluble compounds that have  allelopathic effect on the growth of onion, carrot, cabbage, eggplant, watermelon and Jew’s mellow seedlings under controlled environment condition. However, more research is needed to identify these possible allelopathic compounds and demonstrate their potential under field conditions.