Allelopathy Potential of Weeds Belonging to the Family

Abstract

Asteraceae consists of 8–10% of angiosperm species, around 1600–1700 genera with 24,000 species (Funk, Susanna, Steussy, & Robinson, 2009). Several plants in the Asteraceae family, especially chromolaena odorata, Helianthus annuus, and Tithonia diversifolia (of which remnants of Ageratum conyzoides, Vernonia amygdalina, and Artemisia annua) are revealed to contain huge amounts of allelochemicals, especially in their leaves, reducing the growth of various plants (Eze & Gill, 1992). Parthenium (Parthenium hysterophorus L.), commonly known as congress grass, carrot weed, ragweed Parthenium, is an invasive poisonous herbaceous annual weed of this family. It decreases pasture productivity, affects livestock health, human health and activities, alters ecology and biodiversity, and competes with crop plants for available environmental resources thereby causing enormous yield loss. Parthenin is revealed to be the principal constituent of this plant which accounts for its allelopathy (Mawal, Shahnawaz, Sangale, & Ade, 2015). Netsere (2015) noticed the allelopathic effect of the whole plant of Parthenium on germination and growth of maize and sorghum. Similarly, the powder extract of Parthenium hysterophorus reduced the germination rate and growth of wheat plants (Anwar et al., 2016). Sorecha and Bayissa (2017) showed the allelopathic effects of different doses of aqueous extracts of leaf, stem, and root aqueous extracts of Parthenium on germination and vegetative growth of peanut and soybean. The allelopathic impact of Parthenium hysterophorus extract on the onion meristematic cell influenced mitotic depression leading to chromosomal deformity such as fragments, stickiness nuclear vacuolation, bridge, laggards, and micronuclei. The reduction of DNA content by Parthenium leads to alteration of normal metabolic activity which is a potential threat to genomic balance (Sinha, 2009). Leaf extract of Parthenium hysterophorus was reported to inhibit the germination rate and root length of Cicer arietinum (Shikha & Jha, 2016). Reported that Parthenium hysterophorus aqueous extract induced pollen sterility in Vicia faba. Observed that the acetone leaf extract of Parthenium hysterophorus inhibited germination and decreased root and shoot length of Cyamopsis tetragonoloba. Siyar et al. (2018) reported that the aqueous extract of leaves, stems, and roots of two weeds of Asteraceae (Artemisia annua and Taraxicum officinalis) had an inhibitory effect on seed germination of wheat and maize, where Artemisia annua proved more phytotoxic than Taraxicum officinalis. Kamal (2011) observed that the allelochemicals released by sunflower hampered germination and decreased the shoot length, root length, fresh weight, dry weight, chlorophyll contents and also reduced the level of hormones, GA, IAA in wheat. Leachate of Achillea biebersteinii was observed to negatively affect percentage and rate of germination and radical and shoot length of pepper. Decreased content of chlorophyll carotenoids and protein was also noticed due to allelochemical stress (Abu-Romman, 2011). Arora, Batish, Singh, and Kohli (2015) showed that Tagetes minuta oil retarded seed germination and suppressed seedling growth of invasive weeds—Chenopodium murale L., Phalaris minor Retz., and Amaranthus viridis L by promoting physiological changes that altered chlorophyll content in these plants. Barroso Aragão et al. (2017) spotted the allelopathic effect of Lepidaploa rufogrisea extracts through reduction of the root growth and germination speed index in Lactuca sativa. Similarly aqueous and methanolic extract of Tithonia diversifolia significantly reduced seed germination, seedling growth, and the biochemical parameters and growth of Vigna unguiculata (Oyeniyi, Odekanyin, Kuku, & Otusanya, 2016).