Allelopathic effects of selected leaf extracts on germination and seedling vigour of medicinal crop Kevatch (Mucuna pruriens L.)

Research Note - Pankaj Oudhia
© 2001,2002,2003 Pankaj Oudhia - All Rights Reserved

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Allelopathic effects of selected leaf extracts on germination and seedling vigour of medicinal crop Kevatch (Mucuna pruriens) were investigated. Fresh samples of leaves of selected plants were collected. To prepare extracts, the crushed leaves were allowed to decay in water in the ratio of 1:10 w/v. Mucuna seeds were soaked in these extracts and observations on germination and seedling vigour were taken. Different selected extracts produced significant allelopathic effects on Mucuna. Calotropis leaf extract was identified as most promising extract whereas Blumea leaf extract was noted as most harmful extract.

Key-words : Allelopathic; Mucuna; Medicinal crop; Jatropha; Acorus; Ipomoea; Blumea; Calotropis; Psoralea; Germination; seedling vigour
Introduction

Mucuna pruriens, locally known as Kevatch or Kevanch, is one of the popular medicinal crops of Chhattisgarh. It is grown as kharif crop. Mucuna has long been known and valued in Indian systems of medicine( Oudhia, 2002; Oudhia and Tripathi, 2002). The allelopathic studies on Mucuna have yet not been done. Allelopathy is relatively a new branch of science. The term ' Allelopathy' includes all biochemical interactions ( inhibitory and stimulatory) among plants, including microorganisms. Different plants have different allelopathic effects on other plants. Negative (stimulatory) allelopathic effects of any plant on germination, seedling vigour, growth etc. of other plants can be utilized to develop bio-stimulators. Similarly, the positive (inhibitory ) allelopathic effects of any plant on other plants can be used to develop ecofriendly, cheap and effective plant killers ( Oudhia, 1999). In order to study the allelopathic effects of water extracts prepared from common medicinal plants viz. Ipomoea carnea, Jatropha curcas, Ipomoea reniformis, Acorus calamus, Blumea lacera, Psoralea corylifolia, Mucuna pruriens (for studing Autotoxicity), Acacia arabica, and Calotropis gigantea (Table-1) on germination and seedling vigour of Mucuna pruriens, a pot experiment was conducted at Research Farm, Srishti Herbal Academy and Research Institute (SHARI) situated at Doomar (Durg). India during 2001-2002.
Materials & Methods

Fresh samples of leaves of selected plants were collected at random at the vegetative stage. To prepare extracts, the crushed leaves were allowed to decay for 24 h in distilled water in the ratio of 1:10 w/v (plant material : water). The extracts were allowed to decay at room temperature (28±2oC ) following which the extract was taken using a sieve (2mm mesh). The bioassay experiment was done in earthen pots filled with neutral clay loam soil. Mucuna seeds were soaked in different extracts for 24 h. As a control, Mucuna seeds were also soaked in distilled water for the same duration. After soaking, 10 seeds of Mucuna were sown in each pot. The experiment was laid out in a randomized block design with four replications; the experiment was repeated twice. Germination was recorded at 5, 7, 9, 11 and 13 days after sowing (DAS) and root and shoot lengths were noted at 13 DAS.
Results and Discussion

Different leaf extracts produced significant effects on germination and seedling vigour of Mucuna seeds. At 5 DAS, Acorus and Ipomoea leaf extracts, at 7 DAS, Acorus leaf extract. at 9 DAS, Jatropha leaf extract, at 11 DAS, Ipomoea carnea, Acorus and Mucuna leaf extracts and at 13 DAS Ipomoea carnea, Acorus, Mucuna and Calotropis leaf extracts resulted in maximum germination whereas at 7 DAS, Psoralea leaf extract and at 13 DAS, Control (water) lowered the germination to the minimum. All extracts produced stimulatory allelopathic effects on germination of Mucuna as compared to control (water) and resulted in higher germination. Lethal effects on germination were not observed. In case of root elongation, significantly superior root elongation was noted in case of Calotropis leaf extract that was at par with elongation produced by Jatropha, Mucuna leaf extracts and control (water) whereas Ipomoea leaf extract resulted in lowest elongation. In case of shoot elongation, maximum elongation was found under control that was at par with elongation produced by all the extracts except Blumea leaf extracts. Blumea leaf extract lowered the elongation to the minimum. In the experiment, different interesting observation were noted. Calotropis leaf extracts has been identified as promising extract having stimulatory allelopathic effects on germination, root and shoot elongation.

Stimulatory allelopathic effects of different parts of Calotropis on several agricultural crops have been reported (Oudhia and Tripathi, 1997, Oudhia, 2001). Blumea leaf extract has been identified as most harmful extracts as it resulted in lowest root elongation. In Mucuna fields of Chhattisgarh, Blumea is a common weed. Although stimulatory allelopathic effects of Blumea on different agricultural crops have been reported (Oudhia et al 1997) but in case of Mucuna it resulted in inhibitory allelopathic effects specially in case of root elongation. This observation confirms the hypothesis advanced by Ashraf and Sen (1978) that same allelochemicals acts differently in response of different crops. The autotoxicity effects of Mucuna leaf exrtract on Mucuna have not been observed. Mucuna leaf extract produced more stimulatory allelopathic effect on germination as compared to control, Jatropha, Ipomoea reniformis, Blumea, Psoralea and Acacia leaf extracts. It has produced comparable root and shoot elongation as compared to maximum elongations. Furthermore , repetition of this experiment under field conditions would provide better understanding of allelopathic phenomenon of these extracts on germination and seedling vigour of Mucuna.
Acknowledgement

The author is thankful to Mr. Umakant Tiwari, Mr. Dhanraj Sahu and Mr. SantRam for their co-operation during this experiment .

References :

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