American-Eurasian Journal of Scientific Research 5 (4): 249-256, 2010 ISSN 1818-6785 © IDOSI Publications, 2010

An Assessment of Phytotoxic Potential of Promising Agroforestry Trees on Germination and Growth Pattern of Traditional Field Crops of Sikkim Himalaya,

A.K. Uniyal and Sachin Chhetri

Doon (P.G.) College of agriculture Science and Technology, Dehradun, UA, India

Abstract: An experiment was undertaken to evaluate the phytotoxic potential of promising agroforestry trees on germination and growth pattern of traditional field crops of Sikkim Himalaya and the investigation revealed the considerable effect of three agroforestry tree species on germination and radical-plumule growth of all the test crops. Among the tested species, Ficus nemoralisa was found least effective with stimulatory to germination and radical-plumule growth in all the test crops except for . Macaranga pustulata significantly inhibited germination and radical-plumule growth of all the test crops except in mungo. Leaf extracts of Alnus nepalensis were found depressive for all the test crops except for Zea mays and least for Vigna mungo, while its bark extracts were less effective for all the test crops with respect to germination and radical-plumule growth. Zea mays was found most resistant, while Brassica nigra was most sensitive test crops. Results of present investigation have shown that these tree species have allelopathic potential and contain water-soluble substances, their effect might be dependent on their concentration in water. They have inhibitory effects at higher concentration but at low concentrations have stimulatory effects. These agriculture crops may be cultivated under Ficus nemoralisa without/or least harm. The importance indexes of agroforestry tree species are followed in order: Ficus nemoralisa > Macaranga pustulata > Alnus nepalensis and the order of agriculture field crops indexes are: Zea mays > Vigna mungo > Triticun aestivum > Pisum sativum > Brassica nigra > Elusin coracana.

Key words: Allelopathy Leaf and bark extract Seed germination Radical-plumule growth Alnus nepalensis Macaranga pustulata Ficus nemoralisa and traditional field crops

INRTODUCTION weed-free zones and other related changes in patterns of vegetation. Allelopathy refers to the beneficial or harmful effects Interactions between trees and crops in agroforestry of one on another plant, both crop and weed may have significant bearing on crop production under species, by the release of several bio-chemicals from integrated land use systems rather than mono agriculture. different plant parts by leaching, root exudation, There may also be competition for light, soil moisture and volatilization, residue decomposition and other processes nutrients between trees and agricultural crops. Therefore, in both natural and agricultural systems. First widely utilization pattern of growth resources and biochemical studied in forestry systems, allelopathy can affect many influence (allelopathy) are equally responsible for poor aspects of plant ecology including occurrence, growth germination and growth of understory vegetation [22]. and plant succession, the structure of plant communities, Commonly cited effects of allelopathy include dominance, diversity and plant productivity. Initially, reduced seed germination and seedling growth, many of the forestry species evaluated had, negative furthermore, physiological and environmental stresses, allelopathic effects on food and fodder crops, but in the pests and diseases, solar radiation, herbicides and less 1980s research was begun to identify forestry species that than optimal nutrient, moisture and temperature levels can had beneficial, neutral, or selective effects on companion also affect allelopathic suppression [9]. Different plant crop . Early research grew out of observations of parts, including flowers, leaves, leaf litter and leaf mulch, poor regeneration of forest species, crop damage, yield stems, bark, roots, soil and soil leachates and their derived reductions, replant problems for tree crops, occurrence of compounds, can have allelopathic activity that varies over

Corresponding Author: A.K. Uniyal Doon (P.G.) College of agriculture Science and Technology, Dehradun, UA, India, E-mail: [email protected]. 249 Am-Euras. J. Sci. Res., 5 (4): 249-256, 2010 a growing season. Allelopathic chemicals can also Alnus nepalensis D. Don commonly called as persist in soil, affecting both neighboring plants as Nepalese alder (utis in ) of family Betulaceae, grown well as those planted in succession. Although in wet temperate regions of Pakistan through Nepal, derived from plants, allelochemicals may be more Northern India, Bhutan, Indo-China and South west China biodegradable than traditional herbicides but may also at an elevation of 4000 to 8000 feet. Utis is a deciduous or have undesirable effects on non-target species, semi deciduous tree with a straight trunk that reaches up necessitating ecological studies before widespread use. to 30 m in height, at lower altitudes, it occurs on moist Selective activity of tree allelochemicals on crops and sites, such as near rivers and in ravines, but it colonize other plants has also been reported. Leachates of the rocky sites exposed by landslips, or lands abandoned chaste tree or box elder can retard the growth of pangola following cultivation. This species has extensively used grass but stimulate growth of bluestem, another as shade bearer in and around cardamom field. Beside pasture grass [18]. Allelochemical concentrations in this, other uses are fuel, fodder and small timber by local the producer plant may also vary over time and in the people. [26, 7]. plant tissue produced. Foliar and leaf litter leachates of Present investigation is therefore, undertaken in view Eucalyptus species, for example, are more toxic than bark to evaluate the allelopathic potential of three Agroforestry leachates to some food crops. [6]. tree species viz: Ficus nemoralisa, Macaranga pustulata Under traditional agro forestry systems in Sikkim and Alnus nepalensis on traditional field crops under Himalayas, several tree species are grown in and around existing agroforestry system of Sikkim Himalayas. The the agriculture fields. Ficus nemoralisa Wall, Macaranga information is expected to encourage the farmers to select pustulata King and Alnus nepalensis D. Don are promising tree and food crop combination to develop a promising tree crops in the agroforestry system of productive, sustainable and ecologically stable Sikkim Himalayas, due to their multiple uses such as agroforestry system in Himalayas of Sikkim. fodder, fuel wood, small timber and shade bearing. These tree species add organic matter through leaf litter, improve MATERIALS AND METHODS physiochemical properties of the soil and ultimately increases the farm income. However, leaf litter of tree The experiments was conducted at Department of species have variable chemical composition and exert Forestry, Doon (PG) College of Agriculture, Science and diverse effects in the soil. Agricultural losses experienced Technology, Dehradun (Uttrakhand, India) situated at by farmers have been ascribed several effects of farm 53’24” (N) latitude and 34’27” (E) longitude. The study trees on traditional field crops [21-23]. consisted of three components viz:-three tree species (a) Ficus nemoralisa Wall commonly called as Dudhilo Ficus nemoralisa, Macaranga pustulata and Alnus in nepali belonging to Moraceae family which is found at nepalensis (b) two extract types (leaf and bark), (c) local an elevation of 1400 to 2200 feet, a small, partly varieties of five traditional food crops (i) Triticum deciduous, glabrous tree that grows up to 50 feet in the aestivum, (ii) Eleusine coracana, (iii) Brassica nigra, (iv) wild but cropped trees are kept close to the ground. In Zea mays, (v) Vigna mungo and (vi) Pisum sativum areas of small farms on marginal lands, F. nemoralisa is planted close to fields and frequently lopped to produce Bioassay: For bioassay study, leaf and bark were numerous leafy branches (nemoralisa) [17]. collected separately from young trees (15 to 20 years) of Macaranga pustulata King ex. Hook.f. commonly Ficus nemoralisa, Macaranga pustulata and Alnus called as Malata in Nepali belonging to Euphorbiaceae nepalensis from their natural occurrence in the Sikkim family. A small or moderate-sized evergreen trees found in Himalayas. the Himalayas from Kumaon eastwards, Northern India, The sun dried leaves and bark sample of each tree Nepal, China (South), Indonesia (Sumatra, Java), Malay species was grind in a mechanical grinder. The powder of Peninsula, Thailand. It is. It is found at an elevation of leaf and bark was taken at the quantity of 2, 5, 10gram 3000 to 6000 feet and the maximum height reaches up to 30 separately from each species and then dissolved in 100ml feet. [17]. The tree regenerates abundantly on landslides, double distilled water in beaker and left for 24 hours at open ground and are also grown on the sides of room temperature (25 2°C). The resulting extract was agriculture fields for small timber, fuel wood and filtered through Whatman no. 1 filter paper and stored in somewhere as fodder by local people to feed their farm conical flasks at 6-10 °C. Thereafter, 2%, 3% animals [26]. and 5% extracts was made for each component.

250 Am-Euras. J. Sci. Res., 5 (4): 249-256, 2010

The effect of extracts on seed germination, radical and All the data were statistically analyzed; findings are plumule growth was tested by placing 100 seeds (five discussed agroforestry tree wise here under. replication of 20 seeds each) of each test crop in petri dishes (9cm diameter) containing two layer of Whatman Germination no.1 filter paper saturated with particular extract at room Alnus Nepalensis: Percent germination was significantly temperature (25 ). A separate control series was placed up reduced under all the leaf extracts in all test crops as using double distilled water. Moisture in the petri dishes compared to control. Maximum percent germination was maintained by adding about one ml of extract or (100%) was found in Zea mays and minimum (10 to 15%) distilled water as required. The numbers of germinated in Brassica nigra in which germination was found seeds was counted daily up to 10 days. Final germination reduced greatly (89.63%) under 5% leaf extracts and radical-plumule length was recorded with the help of respectively, as compared to control. Maximum percent metered scale for 10 randomly selected seedlings for each germination (100.0%) was found in Triticum aestivum replicate. Statistical analysis was done to compare the (3%), while the minimum (51.5%) percent germination with mean values using least significant difference ((LSD) maximum reduction (43.71%) under bark extracts was test (P<0.05) [24]. found in Eleusine corcana (2%). On the other hand, maximum (2.07%) stimulation was found in Pisum sativum RESULTS (2%) and Brassica nigra (3%) over control (Table 1 and Figure 1). After completion of 10 days of experiment, final germination was recorded in percentage under all the Macaranga Pustulata: Percent germination was found treatments. Similarly, radical and plumule length was also significantly reduced under all the aqueous extracts in all measured of minimum 10 germinated seeds (seedlings) on the test crops as compared to control. Maximum percent the same day under each treatments including control. germination (81.5%) was recorded in Vigna mungo (2%),

Table 1: Effect of leaf/bark extract of three agroforestry trees on germination percentage of traditional food crops at 10 days Test Crops Extract ------Leaf Triticum aestivum Eleusine coracana Brassica nigra Vigna mungo Zea mays Pisum sativum Alnus nepalensis 2% 31.50b15.00 b 15.10b60.00 b100.00 ab28.50 (-67.85) (-83.60) (-84.45) (-35.82) — (-70.46) 3% 26.50b 13.50b 11.50b 78.50ab 100.00a 46.50b (-72.95) (-85.24) (-88.08) (-16.04) — (-51.81) 5% 25.10b11.50 b 10.00b83.50 a100.00 ab36.50 (-74.48) (-87.43) (-89.63) (-10.69) — (-62.17) Control 98a 91.50 a 96.50 a93.50 a100.00 a96.50 a Bark 2% 98.50a 51.50b 90.00ab 91.50ab 88.50ab 98.50a (+0.51) (-43.71) (-6.73) (-2.13) (-11.5) (+2.07) 3% 100.00a 65.00ab 98.50a 83.50b 75.00b 96.50b (+2.04) (-28.96) (+2.07) (-10.69) (-25) — 5% 95.00a60.00 b86.50 b95.00 a91.50 ab96.50 (-3.06) (-34.42) (-10.36) (+1.60) (-8.5) — Control 98 ab 91.50 a 96.50 a 93.50 a 100.00 a 96.50 b Leaf Macaranga pustulata 2% 13.50b 20.00b 0.0 81.50ab 35.00b 38.50b (-86.22) (-78.14) (-100) (-12.83) (-65) (-60.4) 3% 11.50b13.50 b 0.0 68.50b38.50 bb55.00 (-88.26) (-85.24) (-100) (-26.73) (-61.5) (-43) 5% 11.50b11.50 b 0.0 60.00b23.50 bb38.50 (-88.26) (-87.43) (-100) (-35.82) (-76.5) (-60.01) Control 98 a 91.50 a 96.50 a93.50 a100.00 a96.50 a Bark 2% 48.50b 11.50b 0.0 90.00ab 30.00b 38.50b (-50.51) (-87.43) (-100) (-3.74) (-70) (-60.4) 3% 33.50b35.00 b 0.0 80.00b21.50 bb41.50 (-65.81) (-61.74) (-100) (-14.43) (-78.5) (-56.99) 5% 33.50b25.00 b 0.0 81.50b18.50 bb31.50 (-65.81) (-72.67) (-100) (-12.83) (-81.5) (-67.35) Control 98 a 91.50 a 96.50 93.50 a100.00 a96.50 a

251 Am-Euras. J. Sci. Res., 5 (4): 249-256, 2010

Table 1: Continued Leaf Ficus nemoralisa 2% 98.50ab 50.00b 96.50a 91.50ab 100.00a 85.00b (+0.51) (-43.51) — (-2.13) — (-11.91) 3% 100.00a 43.50b 91.50ab 85.00b 100.00a 93.50ab (+2.04) (-52.45) (-5.18) (-9.09) — (-3.10) 5% 100.00a48.50 b 88.50b95.00 a100.00 ab83.50 (+2.04) (-46.94) (-8.29) (+1.60) — (-13.47) Control 98 b 91.50 a 96.50 a93.50 a100.00 a96.50 a Bark 2% 100.00a46.50 b 95.00a91.50 b100.00 aa96.50 (+2.04) (-49.18) (-1.55) (-2.13) — — 3% 98.50b45.00 b 91.50b91.50 b100.00 ab85.00 (+0.51) (-50.81) (-5.18) (-2.13) — (-11.91) 5% 98.50b 38.50b 95.00a 95.00a 100.00a 93.50ab (+0.51) (-57.92) (-1.55) (+1.60) — (-3.10) Control 98.00b 91.50a 96.50a 93.50ab 100.00a 96.50a (Value in parenthesis indicate % stimulation (+) and % reduction (-) in percent germination over control). Different letters in column indicate significant difference among treatments at P<0.05).

10 Leaf Bark 5 0 -5 -10 -15 -20 T. aestivum E. coracana B. nigra V. mungo Z. mays P. sativum -25 -30 -35 -40 -45 -50 -55 -60 Reduction/ Stimulation % -65 -70 -75 -80 -85 -90 Test crops Fig. 1: Effect of leaf and bark extract of Alnus nepalensis on germination of test crops

120 Leaf Bark 100

80

60

Reduction % 40

20

0 T. aestivum E. coracana B. nigra V. mungo Z. mays P. sativum

Test crops Fig. 2: Effect of leaf and bark extract of Macaranga pustulata on germination of test crops whereas no germination (0.00%) was recorded in Brassica (2%), whereas no germination (0.00%) was recorded in nigra with maximum (100%) percent reduction under all Brassica nigra with maximum (100%) percent reduction the extracts when compared to control. Similarly, maximum under all the bark extracts when compared to control percent germination (90%) was recorded in Vigna mungo (Table 1 and Figure 2).

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Table 2: Effect of leaf/bark extract of three agroforestry trees on radicle and plumule growth of traditional food crops Test crop ------Triticum aestivum Eleusine coracana Brassica nigra Vigna mungo Zea mays Pisum sativum ------Extract Radical Plumule Radical Plumule Radical Plumule Radical Plumule Radical Plumule Radical Plumule Alnus nepalensis Leaf 2% 0.83b 0.81b 0.69b 0.64b 0.71b 0.87b 0.76b 0.72b 7.96ab 3.58ab 0.62b 0.35b (-92.01) (-89.95) (-88.78) (-81.34) (-77.81) (-65.47) (-79.12) (-91.67) (+5.29) (+8.15) (-87.84) (-82.5) 3% 0.57b 0.62 b 0.57b 0.63b0.88 b0.98 b0.42 b 0.48 b 8.52 a 4.11 a 0.94 bb 0.63 (-91.51) (-92.30) (-90.73) (-81.63) (-72.5) (-61.11) (-88.46) (-94.45) (+12.86) (+24.16) (-81.56) (-68.5) 5% 0.45b 0.42 b 0.33b 0.39b0.78 b0.90 b0.34 b 0.46 b 7.65 b 2.89 b 0.45 bb 0.46 (-95.67) (-94.78) (-94.63) (-88.62) (-75.62) (-64.28) (-90.65) (-94.68) (+1.19) (-12.68) (-91.17) (-77.00) Control 10.4a 8.06 a 6.15 a 3.43 a3.2 a2.52 a3.64 a 8.65 a 7.56 a 3.31 abbb 5.10 2.00 Bark 2% 3.44b 2.12b 2.03b 2.76ab 2.06ab 2.36ab 3.48a 4.58ab 5.87b 3.07a 4.26ab 2.23a (-66.92) (-73.69) (-66.99) (-19.53) (-35.62) (-6.34) (-4.39) (-47.05) (-22.35) (-7.25) (-16.47) (+11.50) 3% 3.02b 2.82b 2.09b 2.61b 2.07ab 2.59a 3.14ab 2.64b 6.21b 3.39a 4.57a 2.13ab (-70.96) (-72.88) (-66.01) (-23.90) (-35.31) (+2.77) (-13.73) (-69.47) (-17.85) (+2.41) (-10.39) (+6.50) 5% 2.39bb 3.10 2.06 bb 2.44 1.39 b2.07 b1.96 bb 2.58 4.92 b 2.32 b 3.51 ba 2.23 (-77.01) (-61.53) (-66.50) (-28.86) (-56.56) (-17.85) (-25.30) (-70.17) (-34.92) (-29.90) (-31.17) (+11.50) Control 10.40aaaa 8.06 6.15 3.43 3.20 a2.52 a3.64 aa 8.65 7.56 a 3.31 a 5.10 ab 2.00 Leaf 2% 0.74b 0.88b 0.80b 0.90b (-) (-) 1.40b 4.68ab 1.44b 1.92ab 1.72b 0.74b (-92.88) (-89.08) (-86.99) (-73.76) (-100) (-100) (-61.53) (-45.89) (-80.95) (-41.99) (-66.27) (-6.30) 3% 0.79bb 0.95 0.76 bb 0.97 (-) (-) 1.30bb 3.40 1.11 b 1.11 b 1.92 bb 0.77 (-92.40) (-88.21) (-87.64) (-71.72) (-100) (-100) (-64.28) (-60.69) (-85.31) (-66.46) (-62.35) (-61.50) 5% 0.64bb 0.88 0.62 bb 0.87 (-) (-) 1.06bb 2.66 0.96 b 0.59 b 1.70 bb 0.49 (-93.84) (-89.08) (-89.91) (-74.63) (-100) (-100) (-70.87) (-69.24) (-87.30) (-82.17) (-66.66) (-75.50) Control 10.4a 8.06 a 6.15 a 3.43 a3.2 2.52 a3.64 a 8.65 a 7.56 a 3.31 ab 5.10 bb 2.00 Bark 2% 2.57bb 2.89 1.11 bb 1.77 (-) (-) 1.43ba 6.90b 2.20 b 2.11 b 1.44 bb 0.63 (-72.28) (-61.14) (-81.95) (-48.39) (-100) (-100) (-60.71) (-20.23) (-70.89) (-36.25) (-71.76) (-68.50) 3% 1.98bb 1.51 1.02 bb 1.59 (-) (-) 1.50bb 5.20 2.13 b 2.13 b 0.98 bb 0.55 (-80.96) (-81.26) (-83.41) (-53.64) (-100) (-100) (-58.79) (-39.88) (-71.82) (-35.64) (-80.78) (-72.50) 5% 1.90bb 2.55 1.05 bb 1.44 (-) (-) 1.81bb 5.67 2.04 b 2.25 b 1.92 bb 0.58 (-81.73) (-68.36) (-82.92) (-58.01) (-100) (-100) (-50.27) (-34.45) (-73.01) (-32.02) (-62.35) (-71.00) Control 10.4a 8.06 a 6.15 a 3.43 a3.2 2.52 3.64 a 8.65 a 7.56 a 3.31 ab 5.10 bb 2.00 Ficus nemoralisa Leaf 2% 11.90a 10.80a 6.01ab 2.97b 1.66b 4.49a 4.23a 9.45a 7.89a 3.99a 5.03a 1.91b (+14.42) (+33.99) (-2.27) (-13.41) (-48.12) (+78.17) (+16.20) (+9.24) (+4.36) (+20.54) (-1.37) (-4.50) 3% 10.40ab 10.80ab 5.30ab 4.03a 2.16ab 5.07a 3.80a 10.94a 7.16ab 3.93ab 3.54b 2.09a (-) (+33.99) (-13.82) (+17.49) (-32.50) (+101.10) (+4.39) (+20.23) (-5.29) (+18.73) (-30.58) (+4.50) 5% 6.36bb 8.21 4.51 bb 2.74 1.73 b3.86 ab2.77 bb 4.04 6.19 b 3.36 b 3.69 ba 2.06 (-38.84) (+1.86) (-26.66) (-20.11) (-45.93) (+53.17) (-23.90) (-53.29) (-18.12) (+1.51) (-27.64) (+3.00) Control 10.4ab 8.06 b 6.15 a 3.43 ab 3.2 a 2.52 a 3.64 ab 8.65 ab 7.56 a 3.31 b 5.10 b 2.00b Bark 2% 10.50b 9.91ab 6.25a 3.91a 3.07b 4.31ab 4.06ab 9.76ab 10.38ab 5.43a 7.19a 2.41ab (+0.96) (+22.95) (+1.62) (+13.99) (-4.06) (+71.03) (+11.53) (+12.83) (+37.30) (+64.04) (+40.98) (+20.50) 3% 13.40a 11.70a 5.82b 3.85a 3.11ab 4.73a 4.16a 11.93a 12.41a 5.65a 5.52ab 2.83a (+28.24) (+45.16) (-5.36) (+12.24) (-2.81) (+87.69) (-14.28) (+37.91) (+64.15) (+70.69) (+8.23) (+41.40) 5% 12.10ab 12.50a 5.95ab 3.43b 3.09b 4.96a 4.36a 10.45ab 11.09a 6.26a 7.33a 3.09a (+16.34) (+55.08) (-9.10) (-) (-3.43) (+96.82) (+19.78) (+20.80) (+46.69) (+89.12) (+43.72) (+54.50) Control 10.40bb 8.06 6.15 a 3.43 b3.20 a2.52 b3.64 b 8.65 b 7.56 b 3.31 b 5.10 b 2.00 b (Value in parenthesis indicate % stimulation (+) and % reduction (-) in percent germination over control). Different letters in column indicate significant differences among different treatments at P<0.05).

Ficus Nemoralisa: Germination percent was significantly recorded in Eleusine coracana, which obviously. has reduced when compared to control, maximum (100%) maximum (57.92 %) reduction under 2 5% extracts. As far percent germination was recorded in Zea mays and as stimulation in germination is concerned, it was Triticum aestivum, whereas the minimum (43.5%) calculated maximum (2.04%) in Triticum aestivum (2%) as germination was recorded in Eleusine coracana, which compared to control (Table 1 and Figure 1). obviously has great (52.45%) reduction under 3% leaf extract, on the other hand, maximum (2.04%) stimulation in Radical and Plumule Growth: Significant effect of leaf germination was recorded in Triticum aestivum under all and bark extract was also experienced in radical and the extracts, over control. Under bark extracts, percent plumule growth of all the test crops under different tree germination was recorded maximum (100%) in Triticum species. Mean values for radical and plumule growth are aestivum and Zea mays and the minimum (38.5%) was discussed here under.

253 Am-Euras. J. Sci. Res., 5 (4): 249-256, 2010

Alnus Nepalensis: Maximum radical (7.96cm) and plumule the minimum radical (3.07cm) in Vigna mungo (2%) length (4.11cm) was found in Zea mays, respectively plumule length (2.41cm) was found in Pisum sativum under 2 and 3 leaf extracts, which was significantly at par under 2% bark extract. A slight reduction was observed with control value for the same species. Minimum radical for radical length (14.28%) in Vigna mungo (3%) while, (0.33cm) length in Eleusine coracana (5%) and plumule there was no reduction in plumule length under all the length (0.35cm) was found in Pisum sativum (2%), radical treatments. Maximum stimulation in radical (64.15%) in length was severely reduced (95.67%) in Triticum Zea mays (5%) and plumule length was enhanced upto aestivum (5%) and plumule length (94.78%) in Triticum 96.82% in Brassica nigra, 5% bark extract when compared aestivum (5%). On the other hand, maximum stimulation in to control (Table 2). radical (12.86%) and plumule growth (24.16%) was recorded in Zea mays under 3% leaf extracts, over control. DISCUSSION Under different bark extracts, maximum radical length (6.21cm) was recorded in Zea mays (3%) and plumule For better agroforestry management, it is necessary length (4.58cm) was found in Vigna mungo (2%), while to identify local tree crops with minimum accumulation of the minimum radical (1.39cm) and plumule length (2.07cm) toxins in the soil. Phytotoxic responses of leaf and bark was observed in Brassica nigra (5%). Great reduction in extracts of various agroforestry tree crops of Garhwal hills radical (77.01%) and plumule growth (73.69%) was on germination and radical and plumule extension of field calculated in Triticum aestivum (2 and 5% respectively). crops have also been reported earlier [3, 27,15, 14]. [21] Plumule length was stimulated up to 11.5% (2%) and 6.5% found Ficus auriculata, the most toxic for germination (3%) in Pisum sativum when compared to control while Ficus palmate inhibit the radical and plumule (Table 2). growth of all the tested crops. Similarly our findings has clearly reveled that leaf extracts of Alnus nepalensis and Macaranga Pustulata: Maximum radical (1.92cm) in Pisum Macaranga pustulata were found most toxic for sativum (3%) and plumule length (4.68cm) was found in germination as well as radical-plumule growth, irrespective Vigna mungo (2%) and the minimum radical (0.62cm) in of different concentrations. Under bark extracts of Alnus Elusin coracana (5%) and plumule length (0.49cm) was nepalensis (Figure 1), the all test crops were found less recorded in Pisum sativum under 5% leaf extracts. Radical affected except for Eleusine coracana with respect to and plumule growth (both-100%) was greatly reduced in germination however, radical and plumule growth was Brassica nigra under all the leaf extracts over control. significantly reduced as compared to control. Bark Bark extract of Macaranga pustulata produced maximum extracts of Macaranga pustulata significantly inhibited radical length (2.20cm) in Zea mays and plumule length the percent germination in all the test crops except in (6.90cm) in Vigna mungo (2%), minimum values for radical Vigna mungo, irrespective of different concentrations. (0.98cm) and plumule length (0.55cm) was calculated in Similarly, radical and plumule growth was severely Pisum sativum under 2% bark extract over control affected under all the concentrations of bark extracts as (Table 2). compared to control (Figure 2). Leaf and bark extracts of Ficus nemoralisa were found less/non effective in Ficus Nemoralisa: Among all the test crops, maximum germination and radical-plumule for all the test crops radical (11.90cm) and plumule length (10.8cm) was except for Eleusine coracana, irrespective of all recorded in Triticum aestivum (2%), while minimum radical concentrations, as compared to control (Figure 3). length (1.66cm) in Brassica nigra and plumule length Among all the test crops, Zea mays was found non (1.91cm) was found in Pisum sativum under 2% leaf effective under different leaf extracts of Alnus nepalensis extract. Great reduction in radical length (48.12%) in but was less effective under bark extracts of this species Brassica nigra (2%) and 53.29% in plumule length was with respect to germination and radical-plumule growth, found in Vigna mungo (5%). On the other hand, maximum leaf extracts were found stimulatory in terms of stimulation for radical length (+16.20%) in Brassica nigra germination and radical-plumule growth as compared to (2%) and plumule length was enhanced upto +78.17% in bark extracts. Eleusine coracana and Brassica nigra Brassica nigra under 2 % leaf extracts when compared to were found sensitive particularly under leaf extracts of control. Maximum radical (12.10cm) and plumule length Alnus nepalensis (Figure 1). Brassica nigra was found (12.50cm) was recorded in Triticum aestivum (5%), while severely affected under the leaf and bark extracts of

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Fig. 3: Effect of leaf and bark extract of Ficus nemoralisa on germination of test crops

Macaranga pustulata, it was followed by Eleusine moderate in soil. However, whatever phytotoxin is coracana (Figure 2). Ficus nemoralisa was found least accumulated in the soil under tree species comes from effective but stimulatory with respect to germination and bark which would be less in amount. Thus the present radical-plumule growth in all the test crops (Figure 3). Our investigation has suggests that these tree species have experience with Ficus nemoralisa with respect to allelopathic potential and contain water-soluble germination and growth of all the test crops are in line substances, their effect might be dependent on their with the earlier findings of Singh et al. [21-23]. Similar concentration in water. They have inhibitory effects at experience with Alnus nepalensis is in agreement with the higher concentration but at low concentrations have findings of Kumar et al. [10]. stimulatory effects. These agriculture crops may be The phytotoxic influences of agroforestry tree cultivated under Ficus nemoralisa without/or least harm. crops might be due to the presence of tannins, phenolics The importance indexes of agroforestry tree species are and other secondary metabolites found in various plant followed in order: Ficus nemoralisa > Macaranga parts [11]. Previous reports indicate that foliage leachates pustulata > Alnus nepalensis and the order of agriculture are potent sources of toxic metabolites and the toxic field crops indexes are: Zea mays > Vigna mungo > effects are species specific [12]. In this investigation, we Triticun aestivum > Pisum sativum > Brassica nigra > also found that leaf extracts were very effective in Elusin coracana. suppressing germination as compared to bark but both leaf and bark extracts were equally effective in ACKNOWLEDGEMENTS suppressing radicle and plumule extension, which is at par with the earlier findings [4, 8, 28, 25, 2, 13, 19, 20, 23]. Authors are thankful to all the earlier researchers Certain allelochemicals may reduce cell division, resulting involve in allelopathy studies, for creating interest to in reduction of shoot-root systems. In addition, an undertake more work in this discipline. indirect association between lower germination and allelopathic inhibition may be the consequence of the REFERENCES inhibition of water uptake [5]. In the context of the present investigation, it is 1. Ai-Ping Wu, Hua Yu, Shu-Qin Gao, Zhen-Ying pertinent to mention here that all the investigated tree Huang, Wei-Ming He, Shi-Li Miao and Ming Dong, crops are used extensively as multipurpose farm trees in 2009. Differential belowground allelopathic effects of Sikkim Himalaya. The allelopathic influence of genus leaf and root of Mikania micrantha. Trees, 23: 11-17. Ficus might be due to high alkaloid contents in them. 2. Ahmed, R., A.T.M., Hoque and M.K. Hossain, 2008. Differential inhibitory effects of various parts of the Allelopathic effects of Leucaena leucocephala leaf same plants are likely due to variability in the amount litter on some forest and agricultural crops grown in of phytotoxic compounds in different plant tissues [16]. nursery. J. Forest Res., 19(4): 298-302 It would be worth to mention here that leaves of these 3. Bhatt, B.P. and D.S. Chauhan, 2000. species are generally used as fodder; therefore, Allelopathic effects of Quercus spp. on crops of phytotoxic accumulation through leaves would be low to Garhwal Himalaya. Allelopathy J., 7: 265-272.

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