Introduction

The relation between man and plants originated with the prehistoric human civilization to modern human civilization. The plants are used not only for maintaining the basic life sustaining needs like food, fuel, shelter, but also for making clothes and natural dye to fabric clothes (Das and Mondal, 2012). Natural dyes occupy an important place in human culture and dye yielding plants were probably discovered early through human curiosity, use, reuse and trials (Cannon and Cannon, 2003; Dogan et al., 2008). Indigenous traditional knowledge on dye yielding plants is very essential for community-based development, future bioprospecting and eco-friendly products. India has a great opportunity for export of natural dyes due to its vast plant wealth and rich traditional knowledge of using natural colorants as dye. Probably the earlier known dyes were indigo (blue dye) and alizarin (red dye) obtained from plants (Bechtold and Mussak, 2009).

In recent times, most of the natural dyes have been replaced by synthetic ones which are used in large scale for coloring the foodstuffs and fabrics. It results in the release of pollutants from the textile and fast-food units. This is one of the major causes for serious health hazards and environmental pollution. There has been an alarming outbreak of a number of diseases and disorders due to over use of synthetic dyes in the industries of food, textile, drug, etc.  Therefore, the need of the hour is to screen natural dyes from the plant sources and select the biodegradable and environment friendly ones for use in the industries.                                                                

In this context, the present study has been carried out to provide the significant information regarding the diversity of dye yielding plant resources of Birbhum and Burdwan districts, West Bengal which will enrich data bank of the existing inventory of Indian dye yielding plants. 

Materials and Methods

The district Birbhum is quite rich in natural resources. It extends over about 4528.61 sq km and is situated between 87°10^' and 88°2^' East longitude and between 23°33^' and 24°35^' North latitude. The district is triangular in shape. The western part of the district is bounded by the forest area of Jharkhand where many tribal people reside. The district Burdwan extends over about 7024 sq km and it is situated between 87°54^' and 87°90^' East longitude and between 23°04^' and 23°06^' North latitude (Figure 1).

Figure 1: Map of the study area

It is bounded on the north by Birbhum and Murshidabad districts, on the east by Nadia District, on the southeast by Hooghly District and  on the southwest by Bankura and Purulia districts. The northwest part of the district is bounded by Dhanbad district of Jharkhand. The tribal people of these two districts are to some extent dependent upon the forest flora for their livelihood and use the plant resources in various ways like for their primary health care, food, fibres, shelter, dye, household implements, etc.

Field investigations were conducted for documentation of dye yielding plants in different villages and adjacent forest areas of Birbhum and Burdwan districts, West Bengal following the methods of Jain (1987) and Jain and Mudgal (1999). To confirm the authenticity of the collected data it has always been crosschecked by interviewing other persons of the same and different localities. The specimens were collected from the adjacent forest area with the help of local informant. The collected plant species have been carefully identified with the help of different Floras (Guha Bakshi, 1984; Maheshwari, 2000; Manilal and Sivarajan, 1982; Panigrahi and Murthy, 1989; Saldanha and Nicolson, 1976; Sanyal, 1994; Varma, 1981). The collected plant specimens have been preserved as herbarium specimen following the method of Jain and Rao (1977).

Perusal of literature reveals that many plants grown in the districts may be of the promising sources of dyes (Agarwala, 1986; Ambasta et al., 2000; Anonymous, 1992; 1997; Das and Rahaman, 2014; Uphof, 2001; Watt, 1889−1893). Those plants have also been included here in this investigation.

Results and Discussion

Total 32 plants were recorded from the Birbhum and Burdwan districts of West Bengal used by tribal and rural people in the preparation of 8 different types of dyes which are of great importance as promising resources of natural colorants. These 32 recorded plant taxa spread over 30 species, 29 genera and 22 families of dicotyledons and 2 species, 2 genera and 2 families of monocotyledons (Table 1).

Table 1: Percentage composition of the recorded plant species and their groups

Among recorded plant species, 26 plants (81.25%) are found in wild and 6 plants (18.75%) are grown as cultivated crops and as garden plants (Figure 2). Considering the habit, the investigated taxa are grouped into – climbers in 2 cases (6.25%), herbs in 3 cases (9.37%), shrubs in 7 cases (21.87%) and trees in 20 cases (62.50%) (Figure 3).

Figure 2: Percentage composition of sources of the recorded plants

Figure 3: Incidence of plants based on habit

The different plant parts like barks (18.75%), flowers (28.12%), fruits (28.12%), latex (3.12%), leaves (9.37%), rhizome (3.12%), seeds (6.25%) and wood (3.12%) are in preparation of 8 different types of dye (Table 2).

Table 2: Percentage composition of plant parts used in dye preparation

Various natural dye obtained from the investigated plants like black from 5 plants, blue from 1 plant, brown from 4 plants, grey from 1 plant, purple from 1 plant, red from 5 plants, violet from 1 plant and yellow from 14 plants (Table 3). The investigated plants have been enumerated alphabetically depending upon their botanical names, along with their local and tribal names, parts used, names of the dyes, their uses and frequency of occurrence (Table  4).

Table 3: Percentage composition of colour obtained from the investigated plants

Table 4: Enumeration of the recorded taxa

Table 4: Continue...

Table 4: Continue...

Twenty plant species, 20 plant genera, 19 plant family were identified as dye yielding   plants by Pathania et al. (2021). A total of 17 species of dye yielding plants belonging to 13 families and 17 genera were recorded. These species are used for dyeing clothes and other items. Different plant parts were utilized, of which fruit (07 spp.) was used in the majority, followed by flowers (05 spp.); bark (04 spp.) and leaves (03 spp.) (Kumari et al., 2019). 

Conclusion

Natural dye yielding plants have immense significance in the socio-economic and socio-cultural life of indigenous ethnic people. The data documented in this study will be helpful to prepare the district as well as state level inventory on dye yielding plant resources. It will help in exploring the promising new sources of natural dyes from the district which may be brought under large scale cultivation for commercial purposes.

Acknowledgement

We are grateful to the tribal and rural people of the Birbhum and Burdwan districts, West Bengal who help us by giving the valuable information of their traditional herbal wisdom.