Allelopathic Effects of Invasive Alien Plant Tithonia diversifolia (Hemsl.) A. Gray on Pisum sativum L.

Abstract

The essential factors for the success of invasive alien plants are considered to be the presence of allelochemicals, which are considered “novel weapons”. The allelochemicals released by invasive plants interact differently with each other, especially native and endemic diversity, and also serve as a biological defense against plant diseases and pathogens. To this end, Tithonia diversifolia (Hemsl.) A. Gray, an emerging invasive alien plant in the northeastern (NE) Himalayas, is scantly investigated in terms of exhibiting allelopathy, despite being an aggressive weed in Mizoram, NE India. Especially, their effects on widely edible crops need to be studied because of their inextricable linkage with food productivity and rural livelihood. Thus, the present investigation was carried out on the allelopathic effects of T. diversifolia, based on the physical parameters such as SH, RL, SL, B, GPe, GPo, GI, GRI and VI on the selected common crop Pisum sativum L. through a pot bioassay experiment. In this respect, two highly invaded sites of T. diversifolia were selected for the collection of soil samples based on the variable disturbance factors. The present result concluded that T. diversifolia has strong stimulatory allelopathic effects on the growth parameters of P. sativum at the initial stage of the seed germination; however, it tends to normalize at the later stage of germination. The infested soil of T. diversifolia was observed to be suitable for growing food crops, although it may take longer to germinate due to the allelopathic effect of T. diversifolia. Nevertheless, wise utilization of the leaf leachates may enhance soil fertility for better production of food crops and facilitate sustainable agriculture.