Supervisors:
Dr. Uppeandra Dhar GBPIHED, Kosi Katarmal Almora 263643, Uttaranchal, India.
Prof. A.R. Nautiyal High-Altitude Plant Physiology Research Centre
Dr. R.S. Rawal GBPIHED, Kosi
Katarmal Almora 263643, Uttaranchal, India.
Summary: Issues related to conservation of rare and endangered plants are receiving considerable attention worldwide. In order to address these issues, it is imperative to develop authentic data base on various aspects of life cycle and biology of such species. The present study is a step in this direction wherein attempt has been made to generate data base on Arnebia benthamii – a critically endangered Himalayan medicinal plant. Over 10,000 species of vascular plants are reported from the Himalayan region, of these nearly 3500 are endemic and 200 are critically endangered.
Arnebia (family Boraginaceae) is a genus of hispid herbs, mostly confined to Asia with a few species occurring in the drier parts of North Africa. Seven species of Arnebia are known to occur in India. These include, A. benthamii, A. euchroma, A. guttata, A. hispidissima and A. nobilis. Arnebia species constitute important herbal drugs of indigenous systems of medicine. Besides medicinal uses they are also popular in Asia for imparting a pleasing red colour to foodstuffs, oils, fats and various galencials. A variety of compounds, such as, naphthaquinones, benzoquinones, alkaloids, triterpenoids, steroids and flavonoids have been isolated and characterized from Arnebia. The naphthaquinones are the major constituents reported from Arnebia.
In the Indian Himalayan Region (IHR), due to over exploitation of A. benthamii for medicinal purposes, the species is classified as critically endangered (Ved and Tandon, 1990). In the present study various aspects, such as, (i) distribution and mapping, (ii) assessment, (iii) variability studies, (iv) reproductive biology and (v) development of propagation techniques were undertaken for understanding biology and designing conservation strategy for successful recovery of A. benthamii.
Assessment of the populations revealed that A. benthamii is distributed from 3000 to 3900 m asl in the region. Valley of Flowers population was found at the lowest altitude (3320 m asl) and Sainikharak-1 at the highest altitude (3875 m asl). Species density was relatively lower in subalpine populations. Garpag population in subalpine zone recorded lowest density (0.78 individuals/m2) and Sainikharak-2 population in alpine zone recorded highest density (3.2 individuals/m2). Relative density of the species varied between 6.8 to 30.1 % in subalpine and between 13.6 to 28.2 % in alpine zones. Frequency of occurrence of the species varied between 40.0 to 56.7 % in subalpine and 51.7 to 70.0 % in alpine zone.
The analysis of demographic patterns revealed progressive population structure at Himtoli, Jelam and Malari; stable structure at Valley of Flowers and Sainikharak-2; degenerative structure at Kathalia, Latakharak and Sainikharak-1, and inconsistent structure at Phurkia, Garpak, Neelkanth and Mana.
Considering the morphological variability of different age states, significant variations were observed among populations. However, variation were non significant within population in all age states. Results of morphological variability were in consonance with the results of genetic variability. Protein profile and isozyme pattern showed considerable variation among populations.
Morphology of the below ground parts revealed that A. benthamii possess tap root system which may or may not be branched at distal end. As the age advances root diameter increases. Scars are formed in the root, which deepen with advancement of age and finally disintegrate. The total biomass increases with age, but root length showed no significant relationship with age.
Studies on reproductive biology showed that species emergence starts in May, flower bud is formed during the same month, anthesis occurs in June second week, flowers are in full bloom by end of June to first week of July, seed formation starts from July last week and seeds are mature by August end to September first week. Senescence starts from September and the plants dry by October at the onset of winter. The species exhibit distyly, pin and thrum type of individuals were present in all the populations studied. However the ratio of pin and thrum never approached the ideal (1:1) state. There was no consistency in superiority of one morph over the other with respect to seed set per inflorescence.
The findings of distribution, assessment, variability and reproductive biology of A. benthamii were supplemented with the propagation studies. Seed germination studies of different populations from alpine and subalpine zone under laboratory and nursery conditions were conducted. Populations from both alpine and subalpine zone exhibited high viability (>90%). Among various pretreatments (KNO3, Thiourea, BAP, NAA, GA3, chilling and chilling +GA3) Thiourea and chilling (14 d) were effective and improved seed germination. In alpine population, seeds treated with thiourea responded better than chilling. However in subalpine seeds prechilling was most effective. The increase in percent germination was greater in alpine as compared to subalpine.
The flowering individuals after seed set were used for vegetative propagation; pooled samples from different populations were considered. The terminal growing points were used for experimental work. Various pretreatments (chilling 10, 20 and 40d) were given to increase rooting percentage. Chilling (40d) gave best response and resulted in 70% rooting as compared to 42% under control.
Development of conventional propagation protocols was supplemented by in vitro methods. Explants were drawn from mature individuals of A. benthamii. Flowering shoots after seed set were brought to the institute nursery and planted in earthen pots until utilized for experiment. Various sterilants (Bavistin, HgCl2, Streptomycin) were used to control infestation. Bavistin 0.25 % for 60 min along with 0.1% HgCl2 for 30 min was effective in explant establishment (85.3%). Streptomycin (1g/L) was effective in controlling bacterial infestation. Various antioxidants (PVP and Pholoroglucinol) along with serial transfer (24, 48, 96h) at different durations were employed for controlling explant browning. Serial transfer after 24 h was found most effective in explant establishment (91.7 %). Different concentrations of BAP with 1 µM of IBA were used for multiplication. Maximum multiplication rate (3.1 individuals/explant) was achieved in combination of 1µM IBA and 4µM BAP. Different concentrations (0, 1, 2, 4 µM) of IBA were used for rooting. 4 µM IBA was found most effective in rooting (77.7%). The plantlets were transferred in sterile sand and soil (1:1) in growth chamber. After 4 weeks, the plantlets were transferred to shade house. The survival of the plantlets ex vitro was 35 % in shade house.
Species revegetation in degraded habitat and prospects of cultivation at different altitudes were investigated. At the end of a growing season 20 % of the transplanted individuals survived in natural population (3700 m asl); 60 % of the individuals survived at Katarmal (nursery conditions 1240 m asl) and 66.7% survived at Lata (2220 m asl).
The study provides comprehensive datasets for various investigated parameters, which can effectively be integrated for developing a suitable conservation strategy for A. benthamii. This strategy in turn can serve as a model study for other high value threatened medicinal plants.
Sumit Manjkhola
Subject : ENVIRONMENTAL PLANT PHYSIOLOGY
Ph. D - Environmental Plant Physiology, HNB Garhwal University, Srinagar
Correspondence Address:
Sumit Manjkhola, CBD/GBPIHED, Kosi-Katarmal, Almora,Uttaranchal-263 643
Work Title
Biology and Conservation of Arnebia benthamii – an endemic medicinal herb of high altitude Himalaya