Pawan Kumar Rana

Persistent occurrence of meiotic abnormalities in a new hexaploid cytotype of Thalictrum foetidum from Indian cold deserts

Thalictrum foetidum L. (Ranunculaceae), a morphologically variable and widely distributed species of temperate and alpine Himalayas is worked out cytologically for the first time from India. Earlier studies from outside India were restricted to chromosome counts and karyotypic analysis. We studied the male meiosis, microsporogenesis and pollen viability in the wild accessions from the cold deserts of Lahaul-Spiti, Kinnaur and Pangi Valley of Himachal Pradesh. Present cytomorphological surveys in the species record the existence of two distinct morphotypes involving plant size; colour and size of leaf/leaflet; dentation of leaflet lobes; and degree of leaf pubescence. All the accessions in the two morphovariants share the same meiotic chromosome number (n = 21) and adds a new intraspecific hexaploid cytotype. The accessions show the phenomenon of cytomixis involving transfer of chromatin material among proximate pollen mother cells (PMCs) and associated meiotic abnormalities like, out of plate bivalents, interchromosomal connections, and laggards, bridges and micronuclei at anaphases/telophases. Microsporogenesis results into abnormal sporads (tetrads with micronuclei, dyads, triads and polyads). The products of such sporads resulted into some pollen sterility and pollen grains of heterogeneous sizes. The persistent occurrence of phenomenon of cytomixis and associated meiotic abnormalities and consequently pollen sterility and pollen grains of heterogeneous sizes in the hexaploid cytotype of T. foetidum seems to be under some genetic factors associated with the genome.

Syncytes during male meiosis resulting in 2n pollen grain formation in Lindelofia longiflora var. falconeri

Abstract  Lindelofia longiflora (Royle ex Benth.) Baill. var. falconeri (Cl.) Brand (Family: Boraginaceae) is investigated cytologically (n= 12) for the first time from the cold deserts of Pangi Valley, Chamba District (Himachal Pradesh) in India. We report the formation of syncytes and 2n pollen grains in the species. During meiosis, the majority of the pollen mother cells (PMCs) exhibited 12 bivalents, equal segregation of chromosomes during anaphases, regular tetrads, and normal‐sized pollen grain formation. Occasionally, two proximate PMCs fused during the early stages of prophase‐I and resulted in the formation of syncytes. The frequency of syncytes in the accession is rather low, at 25 out of 1866 (1.33%). Such syncyte PMCs are detectable during meiosis due to their larger size compared to typical PMCs. The syncytes or polyploid cells showed normal 24 bivalents and depicted perfectly regular meiotic course. But the products of such PMCs yield 2n or larger sized pollen grains that are almost double the size of typical normal or n pollen grains. The origin of syncytes as a consequence of the fusion of meiocytes during the early stages of meiosis‐I could be attributed to low temperature stress conditions prevailing in the Pangi Valley, where temperature during May and June dip to below freezing, the time the plants enters the reproductive/flowering bud stage. It is possible that such apparently fertile 2n pollen grains originating from syncytes might play a role in the origin of intraspecific polyploids in the species.

Structural heterozygosity and cytomixis driven pollen sterility in Anemone rivularis Buch.-Ham. ex DC. from Western Himalaya (India)

Meiotic studies have been carried out on 12 accessions of Anemone rivularis from different regions of Western Himalaya. The accessions from Chamba, Kullu and Kinnaur districts of Himachal Pradesh and Uttarkashi district of Uttarakhand showed a normal meiotic course leading to high pollen fertility (87–100%). However, the accession scored from Saat Tal, Uttarakhand showed structural heterozygosity for reciprocal translocations. This is the first report of occurrence of structural heterozygosity in the species. Out of the 604 analysed pollen mother cells (PMCs), 38.41% (232) showed quadrivalent formation at diakinesis and metaphase-I. Comparison of chiasma frequency was also performed among selected populations using one-way analysis of variance (ANOVA), which showed significant differences. The occurrence of cytomixis involving inter PMC transfer of chromatin material among neighbouring meiocytes (45.68%) was also observed. PMCs at anaphases/telophases showed laggards (31.25%) and chromatin bridges at A-I/T-I and A-II/T-II (21.02%) leading to abnormal microsporogenesis. Consequently, abnormal sporads such as triads (66.67%), polyads (3.33%) and triads with micronuclei (0.83%) were formed. Structural heterozygosity and inter PMC chromatin material transfer in the individuals of the species seem to be responsible for the reduction in pollen fertility (67.8%) and formation of pollen grains of heterogeneous sizes.

Uses of Local Plant Biodiversity among the Tribal Communities of Pangi Valley of District Chamba in Cold Desert Himalaya, India

Pangi Valley is the interior most tribal area in Himachal Pradesh of Northwest Himalaya. An ethnobotanical investigation is attempted to highlight the traditional knowledge of medicinal plants being used by the tribes of Pangi Valley. Various localities visited in the valley 2-3 times in a year and ethnobotanical information was collected through interviews with elderly people, women, shepherds, and local vaids during May 2009 to September 2013. This paper documented 67 plant species from 59 genera and 36 families along with their botanical name, local name, family name, habit, medicinal parts used, and traditional usage, including the use of 35 plants with new ethnomedicinal and other use from the study area for the first time. Wild plants represent an important part of their medicinal, dietary, handicraft, fuel wood, veterinary, and fodder components. These tribal inhabitants and migrants depend on the wild plant resources for food, medicines, fuel, fibre, timber, and household articles for their livelihood security. The present study documents and contributes significant ethnobotanical information from the remote high altitude and difficult region of the world, which remains cut off from rest of the world for 6-7 months due to heavy snowfall.

A profile of male meiosis, chromosomal variation and status in species of Impatiens from North-West Himalaya in India

Abstract Impatiens (Balsaminaceae), a genus of over 1000 species, is represented by 209 species in India, particularly in South India and Himalayas. In spite of attempts made by several Indian cytologists, the chromosome counts are available for only 95 species, through karyological studies, or pollen mitosis or meiotic preparations. The investigated species revealed a considerable amount of dysploid chromosomal variation. We have studied male meiosis in 53 accessions from 14 species collected from unexplored regions of North-West Himalaya in India. Chromosome numbers were confirmed for nine species and numbers different from earlier records were found in five species. Four species were documented for chromosome counts for the first time. Out of the 14 species covered presently, nine species possessed dysploid cytotypes with different diploid chromosome counts. Five species possessed more than one diploid chromosome counts. Dysploidy seems to be quite favourable for causing chromosomal variation in the genus. Based on compiled chromosomal data, it is apparent that there is a lot of variation in base numbers. Among the different basic numbers prevalent in the genus, we are of the opinion that x = 7, x = 8, x = 9 and x = 10 seem to be the most common. In addition, a list of North-West Himalayan species of the genus which are yet to be worked out chromosomally and those depicting chromosomal variation has also been included.

Chromosome count, meiotic abnormalities and pollen sterility in Lahaul sweetvetch (Hedysarum astragaloides Benth. ex Baker, Fabaceae), an endemic and threatened species from India

Abstract Male meiotic studies were carried out on eight different accessions of Hedysarum astragaloides Benth. ex Baker (Fabaceae), an endemic and threatened species of northwest Himalaya, India. Although genetic factors such as meiosis, chromosome number, and ploidy level may be causative for the evolution, endemism, rare distribution or even extinction of the species, no detailed information exists. Keeping this in mind H. astragaloides has been studied cytologically. Male meiotic investigations revealed diploid level (2n=2x=14) for species and normal meiotic course in the accessions from the Manali Hills resulting in nearly 100% pollen fertility. However, the accessions scored from the Manimahesh Hills and Pangi Valley depicted inter-pollen mother cell transfer of chromatin material and structural heterozygosity for reciprocal translocations. Consequent upon these meiotic anomalies, some pollen sterility (21%) resulted. On account of this sweeping genetic outcome, the incidence of anomalies such as this in an endemic and threatened species warrants grave consideration. It is sensible to conclude that conservation measures should include the collection of germplasm from the localities where plants are meiotically stable with high gametic fertility, to ensure good germination and healthy plants for future use. Seeds from meiotically normal individuals should be given priority for inclusion in seed banks.