Namrata Sharma

Pattern of Resource Allocation of Six Plantago Species with Different Breeding Systems

Plantago exhibit great deal of differences in the breeding system. The reproductive effort calculated on the basis of, (i) dry biomass of foliar and floral parts and (ii) seed output-weight (mg) per unit leaf area (cm2), exhibits relation with breeding system. The predominantly inbreeding taxa invest higher reproductive effort compared to their outbreeding allies. In terms of sex allocation strategies, the outbreeding species like P. lanceolata, P. lagopus invest more to the development of floral features and to male functions. On the contrary, inbreeding species such as P. patagonica, P. drummondii, and P. ovata invest greater resources to the female function.

Genetic systems of six species ofPlantago (Plantaginaceae)

Investigation of the genetic system of six species ofPlantago has revealed striking differences in their breeding and meiotic systems.Plantago patagonica is an inbreeder on account of preanthesis cleistogamy, whereasP. lanceolata is an obligate outbreeder, as it is self-incompatible.Plantago drummondii, P. lagopus, P. ovata, andP. major show mixed mating but in varying proportions. In terms of their energy budgets, outbreeding species invest more in floral advertisement and male function, while inbreeders invest more in female function. The contribution of the meiotic system to genetic variability, as revealed through recombination index, is more important in the inbreeding species.

Cytology as an Important Tool for Solving Evolutionary Problems in Angiosperms

The usefulness and reliability of cytological methods for studying evolutionary problems has been recognized for a long time. Cytological characters used for determining similarities/differences between various taxa include chromosome number, their form and behaviour. While information on chromosome number pinpoints the role of numerical variations, karyotypic studies help in understanding the role of structural changes in the evolutionary process. Important karyotypic aspects used to evaluate relationships between different taxa include absolute/relative size of chromosomes, position of primary constrictions and number of chromosomes with nucleolus-organizing regions. While chromosomes of different size/form can be studied by simple squashing and solid staining techniques, for establishing relationship between taxa having uniform karyotypes, chromosome banding and fluorescence in situ hybridization techniques are employed. Putative grouping of chromosomes and their behaviour during reduction division has been used in many cases for determining base number, ploidy level, type of ploidy and also for detecting structural chromosomal changes that a taxon might have undergone during evolution. Information on chromosome pairing in allopolyploid crop plants also assist in elucidating the evolutionary phenomenon involved in their production. Despite the advantages conferred by chromosomal information, it has rarely been used as an independent indicator of relationships between different groups. It is because the phenotypic aspects of the chromosomes cannot be more informative than the expression of genes as seen in the morphology of a plant. For determining with great certainty the relationship between various taxa, chromosomes need to be viewed in conjunction with other aspects of an organism as breeding system, habit, morphology, distribution and biochemistry.

Molecular and functional characterization of two isoforms of chalcone synthase and their expression analysis in relation to flavonoid constituents in Grewia asiatica L

Chalcone synthase constitutes a functionally diverse gene family producing wide range of flavonoids by catalyzing the initial step of the phenylpropanoid pathway. There is a pivotal role of flavonoids in pollen function as they are imperative for pollen maturation and pollen tube growth during sexual reproduction in flowering plants. Here we focused on medicinally important fruit-bearing shrub Grewia asiatica. It is a rich repository of flavonoids. The fruits are highly acclaimed for various putative health benefits. Despite its importance, full commercial exploitation is hampered due to two drawbacks which include short shelf life of its fruits and larger seed volume. To circumvent these constraints, seed abortion is one of the viable options. Molecular interventions tested in a number of economic crops have been to impair male reproductive function by disrupting the chalcone synthase (CHS) gene activity. Against this backdrop the aim of the present study included cloning and characterization of two full-length cDNA clones of GaCHS isoforms from the CHS multigene family. These included GaCHS1 (NCBI acc. KX129910) and GaCHS2 (NCBI acc. KX129911) with an ORF of 1176 and 1170 bp, respectively. GaCHSs were heterologously expressed and purified in E. coli to validate their functionality. Functionality of CHS isoforms was also characterized via enzyme kinetic studies using five different substrates. We observed differential substrate specificities in terms of their Km and Vmax values. Accumulation of flavonoid constituents naringenin and quercetin were also quantified and their relative concentrations corroborated well with the expression levels of GaCHSs. Further, our results demonstrate that GaCHS isoforms show differential expression patterns at different reproductive phenological stages. Transcript levels of GaCHS2 were more than its isoform GaCHS1 at the anthesis stage of flower development pointing towards its probable role in male reproductive maturity.

Inter-population chromosome variation in Artemisia nilagirica L.

Artemisia nilagirica L. (fam. Asteraceae), a widely distributed economically important plant exhibits lot of morphological variability and forms populations at different altitudes in the Jammu Province of J and K State, India. Present communication puts on record variability in chromosome counts in two populations of this species. The chromosome counts of the two populations varied in the way that a common base number could not be applied to them. One population named as Rajouri population shows 2n = 54, while the other named Jammu population revealed 2n = 34. The two populations when compared for their pollen viability and seed set show considerable differences. The Rajouri population was quite stable with high pollen viability and good, healthy seed set on open pollination, but Jammu population showed low pollen viability and seed set. Both these populations however showed a drastic reduction in seed set on unassisted selfing.

Genetic systems in chillies II. Meiotic system of three cultivars of Capsicum annuum L.

Abstract Three varieties of chillies, namely, Pusa Sadabahar (PSB), Pusa Jawala (PJ) and Kashmir Long-1(KL-1), commonly cultivated in the area of study i.e. Jammu, J&K state (India) were analysed for details of their meiotic system. These three matched in their diploid chromosome number (2n=24) and resembled each other closely in details of karyotype, meiotic behaviour and recombination index. Some leaks were observed in the variety Kashmir Long-1 in the form of a desynaptic and a trisomic individual. Later, showed trisomy for the longest pair in the chromosome complement. Desynaptic individual showed irregular meiotic behaviour and low pollen viability. It was unable to set any fruit.

Reproductive biology ofPlantago L. III. Floral adaptation to wind pollination inPlantago lagopus L.

Plantago lagopus L., a weed belonging to family Plantaginaceae, has several features that allow its pollen to be easily drifted by wind. The syndrome of anemophily sensu Faegri and van der Pijl is represented in this species. In addition, some individuals in all populations are male sterile, and all plants contain dimorphic pollen within their pollen sacs. Pollen dimorphy ensures the dual requirement of dispersal over long distances and easy trapping by the plumose stigma.

Efficient In Vitro Regeneration, Analysis of Molecular Fidelity and Agrobacterium tumifaciens - Mediated Genetic Transformation of Grewia asiatica L.

Grewia asiatica is a dietotheraphtically important fruit bearing shrub, indigenous to India. It is a rich resource of triterpinoids and flavonoids and possesses many putative health benefits. Two of the drawbacks which include short shelf life of its fruits and larger seed volume impedes its full exploitation. Seed abortion for developing seedless cultivars through biotechnological interventions is a viable option. One of the prerequisites for such strategy is to develop an efficient plant regeneration and transformation protocols in G. asiatica. Against this backdrop multiple shoot induction was achieved from nodal explants with axillary buds, on culturing in Woody Plant medium (WM) fortified with 3% (w/v) sucrose, 2 × 10-5M Kinetin (Kn) and 1 × 10-5M indole-3-butyric acid (IBA) giving rise to an average of 4.25 ± 0.71 microshoots per explant. More than 90% of the explants formed micro-shoots with mean shoot length of 10.5 ± 1.96 cm leading to whole plant regeneration. Healthy regenerated shoots showed prolific rooting of more than 95% on WM supplemented with 4.8 × 10-6M indole-3-butyric acid (IBA). Following simple hardening procedures, rooted plantlets, were transferred to soil-sand (1:1; v/v) with about 92% success. Genetic fidelity was assessed using random amplified polymorphic DNA (RAPD). Additionally, Agrobacterium-mediated genetic transformation protocol was developed using A. tumefaciens strain GV2260 harboring binary vector p35SGUSINT containing hygromycin phosphotransferase gene (hpt). Transformation was verified by GUS assay and detection of the hygromycin phosphotransferase (hpt) by polymerase chain reaction. In vitro regeneration and ensuing molecular fidelity of regenerated plants and transformation studies are hitherto unreported for G. asiatica.

Interpopulation variability in Artemisia glauca Pall. ex Willd.- studies on three distinct cytotypes

Three wild populations of Artemisia glauca Pall. ex Willd. occurring in the Pir Panjal mountain ranges and in the Kishtwar Himalayas of Jammu and Kashmir State, India, have been analysed for their meiotic systems and reproductive output. Of the three, two namely Poonch and Rajouri populations have a chromosome count of 2n = 18, while the third population named as Kishtwar population has 2n = 36. These are in all probability diploid and tetraploid cytotypes. While the tetraploid Kishtwar population shows stunted growth, diploid ones show little variation at the morphological level but display prominent interpopulation differences in detail of chromosome size and chiasmata frequency. Meiotically Poonch population is more stable than Rajouri. The differences in ploidy level and chromosome constitution affect the reproductive output in these species. Although all of them show high degree of inbreeding depression (revealed by total absence of healthy seeds on forced selfing), seed and fruit set on open pollination also is extremely low. Of the three, Poonch population sets the highest percentage of healthy seeds.

Resource allocation in relation to meiotic system in two species of Artemisia from North-West Himalayas

Artemisia scoparia Waldst & Kit and Artemisia nilagirica (C. B. Clarke) Pamp. are two economically important species of Artemisia L. (F: Asteraceae) forming distinct populations in subtropical to subtemperate regions of Jammu division in Jammu and Kashmir state, India. Both these species have perennial root stocks through which they produce aerial offshoots each year and spread vegetatively. Species differ in their sex expression as well as in reproductive output through sexual reproduction. A probe into their genetic system revealed them to be matching in breeding system as both were predominantly outcrossed. However they differ markedly in their meiotic system and reproductive effort (both sexual and vegetative). The differences were both inter as well as intraspecific. Fruit set in plants of Artemisia scoparia is high and plants are perfect diploids with 2n = 16 (n = 8). Fruit set in A. nilagirica is comparatively low. It also exhibits interpopulation chromosomal variability in the form of polyploid and aneuploid races. In A. nilagirica, two different chromosome numbers which were predominant are 2n = 34 and 2n = 54. Species are also variable in their reproductive effort. The population with lower reproductive output through sexual reproduction has a higher investment in rootstock and vice versa. This paper tries to elaborate the variability in chromosome complement, reproductive output and reproductive effort of these species.