Influences of wild crucifers on life history traits and flight ability of the diamondback moth,Plutella xylostella (Lepidoptera: Yponomeutidae)

The larvae ofPlutella xylostella were fed on five wild crucifers,Capsella bursa-pastoris, Lepidium virginicum, Cardamine flexuosa, Rorippa indica, R. islandica and a crop, cabbage. The developmental period of the immature stages, adult longevity, preoviposition period, fecundity and morphometrical characters of the adults were measured. The flight activity of the adults was also measured by the tethered flight method. All the wild plants except forR. islandica were less suitable host plants than cabbage, and larvae which were fed on these less suitable plants emerged as smaller adults with shorter wings. The smaller female adults had lower fecundity but a higher flight activity. Smaller adults measured in terms of their pupal weight among individuals fed on the same host plant had longer wings. These smaller adults with longer wing flew more actively.     

The diploidRorippa islandica discovered in Southern Europe

A revison of herbarium material ofRorippa, revealed the presence of the diploidRorippa islandica (Oeder exMurr.) Borb. (2n=16) in several localities in Jugoslavia (Bosnia-Hercegovina and Montenegro), and probably also in Italy (Etruria). All localities occur in altitudes above 1400 m a.s.l. and constitute an extension of the distribution area of this species to Appenine and Balkan Peninsula.     

Plant-derived smoke stimulates germination of four herbaceous species common in temperate regions of Europe

Germination responses to aerosol smoke and its aqueous solution (smoke–water) were studied in laboratory for six species common throughout temperate Europe: four annual weeds from the Brassicaceae family (Camelina microcarpa, Capsella bursa-pastoris, Descurainia sophia and Sisymbrium orientale), and two perennial Plantago species (P. lanceolata and P. media) inhabiting natural grasslands. It was hypothesized that smoke enhances germination for these species despite they are not fire-adapted. Both smoke treatments increased the final germination percentage for C. bursa-pastoris and D. sophia by fourfold to fivefold, for C. microcarpa by 73–224 % and for P. lanceolata by 26–41 % compared to the control. S. orientale and P. media showed high (>80 %) germination in the control with no significant response to smoke–water. These results confirm the occurrence of smoke-stimulated germination among species of the European natural flora inhabiting non-fire-prone habitats, suggest more successful seedling recruitment for smoke-responsive species with climate change-driven increase in fire frequency and can be used in the cultivation of the species or in weed control.     

Cytological evaluation of Apiaceae Lindl. from Western Himalayas

The present paper deals with cytological studies on 31 populations covering 17 species belonging to 10 genera of Apiaceae from Western Himalayas. The chromosome numbers in the two species as Chaerophyllum capnoides (n = 11) and Heracleum brunonis (n = 11), along with additional cytotypes for Pimpinella acuminata (n = 9) and Sium latijugum (n = 12) have been reported for the first time on world-wide basis. The genus Pleurospermum, although cytologically worked out earlier from outside India, its species densiflorum (n = 11) makes first representation of the genus from India. Besides, the chromosome number in Chaerophyllum aromaticum (n = 11) have been worked out for the first time from India. The course of meiosis varies from normal to abnormal in different populations of Chaerophyllum villosum, Pimpinella achilleifolia and Sium latijugum while abnormal meiotic course has been observed in all the studied populations of Chaerophyllum acuminatum, C. aromaticum, C. capnoides, Pimpinella acuminata, P. diversifolia, Pleurospermum densiflorum and Vicatia coniifolia. Such taxa are marked with meiotic abnormalities in the form of cytomixis, chromatin stickiness, formation of laggards and bridges resulting into abnormal microsporogenesis. The occurrence of structural heterozygosity has been recorded in the Chaerophyllum acuminatum and C. aromaticum. The effect of these abnormalities is clearly seen on the pollen size and fertility.     

Lipid content and fatty acid composition of seeds of Capsella species from different geographical locations

Seeds of natural populations of Capsella bursa-pastoris, collected from temperate regions, weighed less and had a higher lipid content than those from colder regions. The long-chain (16:0, 18:0, 18:1, 18:2 and 18:3) and very long-chain (20:0, 20:1, 20:2 and 20:3) fatty acid compositions were, however, quite similar in the lipids of all the seed samples which indicates a rigid genetic, rather than environmental, control of fatty acid biosynthesis. Characteristics of the seeds of the diploid species C. rubella and C. grandiflora were similar to those of the tetraploid C. bursa-pastoris, with the exception of the distinctly lower lipid content in C. grandiflora seeds.     

Molecular systematics ofCardamine and allied genera (Brassicaceae): Its and non-coding chloroplast DNA

Representatives of the generaCardamine, Dentaria, Nasturtium, Rorippa andArmoracia (Brassicaceae) were analyzed to elucidate their phylogenetic relationships based on nuclear (ITS) and non-coding chloroplast (cp) DNA sequences.Dentaria seems to be polyphyletic. The two studiedDentaria species group with differentCardamine clades, and it is argued thatD. bulbifera is an allopolyploid originating from a hybridization between aCardamine and aDentaria species. In the ITS tree,Nasturtium andRorippa form well supported clades but their relationship toCardamine andArmoracia remains unresolved. In the cpDNA tree,Nasturtium groups together withCardamine. Hybridization events apparently played a role in the evolution ofNasturtium. TheCardamine/Nasturtium clade is separated from a clade placingRorippa andArmoracia together.Armoracia is closely related toRorippa. Analyses of the 19Cardamine species studied revealed three main groupings, a northern hemispheric and two southern hemispheric groups. Within the northern hemisphere taxa theC. pratensis complex forms a well supported clade which seems to be closely related toC. amara, C. raphanifolia andC. flexuosa. The positions ofC. hirsuta andC. impatiens are uncertain. The two southern hemisphere clades consist of New Guinean species and south-eastern Australian/Tasmanian and subantarctic species, respectively. They may reflect migration routes from the northern to the southern hemisphere, but further studies are necessary to fully understand the evolution of the bihemispheric distribution pattern ofCardamine.     

On the origin of the widespread self-compatible allotetraploid Capsella bursa-pastoris (Brassicaceae)

Polyploidy, or whole-genome duplication, is a common speciation mechanism in plants. An important barrier to polyploid establishment is a lack of compatible mates. Because self-compatibility alleviates this problem, it has long been hypothesized that there should be an association between polyploidy and self-compatibility (SC), but empirical support for this prediction is mixed. Here, we investigate whether the molecular makeup of the Brassicaceae self-incompatibility (SI) system, and specifically dominance relationships among S-haplotypes mediated by small RNAs, could facilitate loss of SI in allopolyploid crucifers. We focus on the allotetraploid species Capsella bursa-pastoris, which formed ~300 kya by hybridization and whole-genome duplication involving progenitors from the lineages of Capsella orientalis and Capsella grandiflora. We conduct targeted long-read sequencing to assemble and analyze eight full-length S-locus haplotypes, representing both homeologous subgenomes of C. bursa-pastoris. We further analyze small RNA (sRNA) sequencing data from flower buds to identify candidate dominance modifiers. We find that C. orientalis-derived S-haplotypes of C. bursa-pastoris harbor truncated versions of the male SI specificity gene SCR and express a conserved sRNA-based candidate dominance modifier with a target in the C. grandiflora-derived S-haplotype. These results suggest that pollen-level dominance may have facilitated loss of SI in C. bursa-pastoris. Finally, we demonstrate that spontaneous somatic tetraploidization after a wide cross between C. orientalis and C. grandiflora can result in production of self-compatible tetraploid offspring. We discuss the implications of this finding on the mode of formation of this widespread weed.Subject terms: Evolution, Polyploidy in plants, Plant evolution, Haplotypes     

Host plant selection of the horse-radish flea beetle Phyllotreta armoraciae (Coleoptera: Chrysomelidae): Feeding responses to glucosinolates from several crucifers

Feeding responses of Phyllotreta armoraciae, a monophagous flea beetle feeding on horseradish, Armoracia rusticana, were evaluated by means of leaf disc tests. Semiquantitative determinations of the glucosinolate contents found in leaves of twelve species of Cruciferae, including horseradish, were performed. The responses of P. armoraciae to the twelve plant species were evaluated, as were the responses to pure glucosinolates and to glucosinolate mixtures occurring in the plants.The glucosinolate content of horseradish consisted of more than 99% allylglucosinolate together with traces of 2-butyl-and benzylglucosinolate. Nearly the same pattern occurred in Brassica nigra, Alliaria petiolata, Iberis umbellata, and Thlaspi arvense, but only the first-mentioned species was acceptable in laboratory bioassays. Nasturtium microphyllum, Sinapis alba, and Sisymbrium officinale did not contain allylglucosinolate as a major component, but nevertheless, these species were acceptable to P. armoraciae in the laboratory. The glucosinolate mixtures isolated from Nasturtium microphyllum, Sisymbrium officinale, Alyssum saxatile, and Cardamine amara were even more stimulating than glucosinolates from horseradish. The two latter species together with Iberis amara and Raphanus sativus were not eaten by P. armoraciae.All acceptable plants contained highly stimulatory mixtures of glucosinolates but several glucosinolates contributed to these mixtures and P. armoraciae did not prefer the glucosinolates of horseradish above those of most other investigated crucifers. Therefore, horseradish cannot be recognized by the beetles solely by its content of glucosinolates. Other feeding stimulants and(or) absence of feeding inhibitors seem to play a major role.

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Zusammenfassung Das Wirtswahlverhalten des monophagen Erdflohs, Phyllotreta armoraciae, der auf Meerrettich, Armoracia rusticana, lebt, wurde mittels Blattscheiben-Tests untersucht.Glukosinolate stimulieren die Futteraufnahme von vielen Insekten, die auf Cruciferen leben. Wahrscheinlich erkennt ein monophages Insekt seine Wirtspflanze durch Reaktionen auf Stoffe die dieser Pflanze eigen sind. Eine Untersuchung der Affinität zwischen P. armoraciae und den Glukosinolaten des Meerrettichs wurde deshalb unternommen.Glukosinolate aus zwölf Cruciferae wurden isoliert, und eine semiquantitative Bestimmung durchgeführt. Gleichzeitig wurden die isolierten Glukosinolat-Mischungen auf Erbsenblattscheiben überführt und die frassstimulierende Wirkung gemessen.Der Glukosinolatinhalt des Meerrettichs besteht aus 99% Allylglukosinolat und Spurmengen von 2-butyl-und Benzylglukosinolat. Fast derselbe Gehalt wurde in Brassica nigra, Alliaria petiolata, Iberis umbellata und Thlaspi arvense gefunden, aber nur die ersterwähnte Art wurde in Labor-Tests akzeptiert. Obwohl Allylglukosinolat keine Hauptkomponente in Nasturtium microphyllum, Sinapis alba und Sisymbrium officinale ist, werden diese Arten doch von P. armoraciae im Labor akzeptiert. Vier anderen Cruciferen werden nicht akzeptiert.Die aus N. microphyllum, S. officinale, Alyssum saxatile und Cardamine amara isolierten Glukosinolat-Mischungen stimulieren die Futteraufnahme mehr als die Glukosinolat-Mischung aus Meerrettich. Nur die Glukosinolat-Mischung aus Iberis amara wirkt weniger stimulierend als die Mischung aus Meerrettich.Pflanzenarten, die von P. armoraciae akzeptiert werden, enthalten Glukosinolat-Mischungen mit hoher frassstimulierende Wirkung. Diese Wirkung ist nicht an einzelne Glukosinolate oder Glukosinolat-Mischungen geknüpft, und P. armoraciae erkennt den Meerrettich unter anderen Cruciferen nicht am Gehalt an Glukosinolaten.Einige Pflanzenarten werden nicht akzeptiert, obwohl sie frassstimulierende Glukosinolate enthalten. Vielleicht fehlen bei diesen Arten andere notwendige frassstimulierende Stoffe, oder (und) sie enthalten vielleicht frasshemmende Stoffe.

     

Aspartate aminotransferase isozymes in the genusCapsella (Brassicaceae): Subcellular location,gene duplication,and polymorphism

The subcellular location of aspartate aminotransferase isozymes (EC 2.6.1.1) in the genusCapsella(Brassicaceae) was studied. The diploid speciesC. grandiflora andC. rubella have three AAT isozymes, including one located in the plastids. Each locus is duplicated in the tetraploidCapsella bursa-pastoris. Variation at the plastid-coding locus exceeded that at the other loci.C. bursa-pastoris had some unique alleles not detected in the diploid species. Segregation in open-pollinated families revealed thatCapsella grandiflora was outcrossing, whereasC. rubella was highly inbred, with most populations homozygous or uniform at all three loci. Inheritance in the tetraploid colonizerC. bursa-pastoris is disomic. This species was also predominantly selfing with outcrossing rates between 2% and 10%.Financial support by the German Research Foundation DFG is gratefully acknowledged.     

Cytology of five species of subfamily Papaveroideae from the Western Himalayas

During the present course, population-based meiotic studies were carried out on five species of subfamily Papaveroideae from selected localities of Kashmir and Himachal Pradesh in the Western Himalayas (India). Varied intraspecific chromosome counts were reported for the first time in Argemone mexicana and Meconopsis latifolia, both existing on 2n?=?2x?=?14. The x?=?7, confirmed for the first time from the newly found diploid cytotype, is suggested to be the primary chromosomal basic number for the Meconopsis. Furthermore, meiotic course was noted to be normal in Argemone ochroleuca, it varied from normal to abnormal in the populations of A. mexicana and Papaver dubium whereas it was invariably found to be abnormal in all the populations of Meconopsis aculeata and M. latifolia. These anomalous taxa were marked with meiotic abnormalities in the form of cytomixis, chromosomal stickiness, unoriented bivalents, formation of laggards and bridges resulting in abnormal microsporogenesis, and production of heterogeneous-sized fertile pollen grains along with reduced pollen fertility.     

Chromosome observations on some eastern North American Eleocharis (Cyperaceae)

Chromosome numbers are reported forEleocharis obtusa var.ellipsoidalis (2n = 10),E. obtusa var.peasei (2n =10),E. engelmannii (2n =10),E. olivacea f.olivacea (2n = 20),E. olivacea f.reductiseta (2n = 20),E. flavescens (2n = 30),E. tenuis var.verrucosa (2n = 20),E. tenuis var.tenuis (2n = 24),E. tenuis var.pseudoptera (2n = 39), a possible hybrid betweenE. tenuis var.pseudoptera and var.tenuis (2n = ca. 34 & 68),E. intermedia (2n = 22),E. tuberculosa (2n = 30),E. smallii (2n = 36), andE. ambigens (2n = 46). Noticeable chromosome size differences inE. tenuis, E. smallii, andE. ambigens are consistent with size differences previously reported by other authors. Variable meiotic pairing configurations were observed inE. flavescens, E. intermedia, andE. tenuis. Chromosome data help verify taxonomic relationships of some taxa and indicate the need for further investigation of others.     

Chromosome counts and chromosome morphology of some selected species

In the years 1976–1981 we studied chromosome counts and karyotypic formulae of the following 29 species of plants from 41 localities (of these 6 from Bohemia, 32 from Moravia, 3 from Slovakia):Batrachium baudotii (Godron) F. W. Schultz,Chenopodium rubrum L.,C. polyspermum L.,C. murale L.,C. ficifolium Sm.,C. opulifolium Schrader ex DC. inLam. et DC.,C. strictum Roth [subsp.strictum, subsp.glaucophyllum (Aellen)Aellen inJust etAellen, subsp.striatiforme Uotila],Arenaria grandiflora L.,Illecebrum verticillatum L.,Spergula morisonii Boreau inDuchartre,Spergularia marginata (DC. inLam. et DC.)Kittel S. marina (L.)Griseb.,S. rubra (L.) J. etC. Presl,Silene conica L.,Sisymbrium loeselii L.,S. volgense Bieb. exE. Fourn.,S. orientale L. [subsp. orientale, subsp.macroloma (A. Pomel)Dvo?ák],S. officinale (L.)Scop.,Descurainia sophia (L.)Webb exPrantl inEngler etPrantl,Nasturtium officinale R. Br. inAiton,Barbarea arcuata (Opiz inPresl J. et C.)Reichenb.,Lunaria annua L.,Soldanella montana Willd.,S. carpatica Vierh. inUrban etGraebner,Lotus tenuis Waldst. etKit. exWilld.,L. uliginosus Schkuhr,Trigonella monspeliaca L.,Geranium sibiricum L.,Lactuca tatarica (L.)C. A. Meyer.     

Characteristics of cadmium accumulation and tolerance in <Emphasis Type="Italic">Rorippa globosa</Emphasis> (Turcz.) Thell., a species with some characteristics of cadmium hyperaccumulation

Characteristics of cadmium (Cd) accumulation and tolerance in Rorippa globosa (Turcz.) Thell., a species with some characteristics of cadmium hyperaccumulation were further investigated and compared with a closely related species, Rorippa islandica. The results showed that there was no phytotoxicity for R. globosa leaves or reduction in biomass when treated with 25 μg Cd g⁻¹, although the concentration of Cd accumulated in the leaves was up to 218.9 μg Cd g⁻¹ dry weight (DW). On the contrary, Cd toxicity was observed in R. islandica leaves by way of determining changes in fresh weight (FW), malondialdehyde (MDA) level and chlorophyll content while treated with 25 μg Cd g⁻¹ DW. R. globosa had stronger self-protection ability than R. islandica to adapt to oxidative stress caused by Cd. Application of Cd significantly increased the activity of superoxide dismutase (SOD) in leaves, the activity of peroxidase (POD) in roots, and the activity of catalase (CAT) in leaves and roots of R. globosa. By contrast, in R. islandica, the activity of antioxidant enzymes was inhibited or unchanged by various Cd treatments. However, R. globosa leaves had higher activity of antioxidant enzymes such as SOD and POD than that of R. islandica. The antioxidative defense systems in R. globosa might play an important role in Cd tolerance. The Cd treatments significantly induced the synthesis of phytochelatins (PCs) in the two species. Leaf PCs and Cd accumulation by R. globosa were much greater than those by R. islandica, but root PCs and Cd accumulation by R. islandica were much greater than those by R. globosa, suggesting that PCs in leaves may be a biomarker of Cd hyperaccumulation, and the synthesis of PCs may be related to an increase in the uptake of Cd ions into the cytoplasm, not the primary mechanism for Cd tolerance.     

Evolutionary Processes Associated with Biological Invasions in the Brassicaceae

This review highlights evolutionary processes in the Brassicaceae which cause, accompany or are a consequence of biological invasions. Case studies in Capsella and Diplotaxis address the genetics of colonising species. The greatest colonising ability in Capsella bursa-pastoris is associated with polyploidy, predominant selfing, and high genetic diversity. Success of colonial populations seems to be due to the introduction of preadapted genotypes. Colonising species in Diplotaxis reveal contrasting evolutionary patterns. Genetic attributes in D. muralis include annuality, polyploidy, and predominant selfing. Very different from Capsella, D. muralis is nearly devoid of genetic diversity as revealed by molecular markers. In contrast to D. muralis, the colonising D. tenuifolia is perennial, diploid, self-incompatible, and displays high genetic diversity. Hybrid speciation, establishment of the hybrids in man-made habitats, stabilisation of their reproductive system, and reproductive isolation from the parent populations were analysed in Cardamine. The Nasturtium example highlights the importance of hybridisation for the evolution of invasiveness. The last case study concentrates on the evolutionary consequences of hybridisation between native and invading Rorippa species. Introgressive hybridisation between the invasive Rorippa austriaca and native Rorippa species is common and widespread in central Europe, and interspecific gene transfer has led to the formation of a new invasive genotype. Each successful invasion presents new aspects and sound case studies are needed in order to understand the ecology and evolution of the colonisation process and to enable us to assess the evolutionary consequences of biological invasions. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cytology of the genus Artemisia (Anthemidae,Asteraceae) in the Western Himalayas

The present study revealed the varied frequency of natural chromosomal abnormalities in 13 populations pertaining to 9 species of the genus Artemisia L. from different localities of Himachal Pradesh (Western Himalaya). Intraspecific chromosome variability has been reported for the first time on worldwide basis in Artemisia vestita (2n = 2x = 36) and from India in A. macrocephala (2n = 2x = 18) and A. scoparia (2n = 2x = 36). Besides, B-chromosomes have been reported here for the first time in A. nilagirica and A. roxburghiana. Most of the populations show anomalous meiotic behaviour resulting in cytomixis, chromosomal stickiness, unoriented bivalents, formation of laggards and bridges which leads to abnormal microsporogenesis, and production of heterogeneous-sized fertile pollen grains along with reduced pollen fertility.     

Enzymatic Relationships and Evolution in the Genus Meloidogyne (Nematoda: Tylenchida)

Thirty populations of Meloidogyne of diverse geographic origin representing 10 nominal species and various reproductive, cytological, and physiological forms known to exist in the genus were examined to determine their enzymatic relationships. The 184 bands resolved in the study of 27 enzymes were considered as independent characters. Pair-wise comparisons of populations were performed in all possible combinations to estimate the enzymatic distances (ED) and coefficients of similarity (S). A phylogenetic tree was constructed. The apomictic species M. arenaria, M. microcephala, M. javanica, and M. incognita shared a common lineage. M. arenaria was highly polytypic, whereas conspecific populations of M. javanica and M. incognita were largely monomorphic. The mitotic and meiotic forms of M. hapla were very similar (S = 0.93), suggesting that the apomictic race B evolved only recently from the meiotic race A. The five remaining meiotic species (M. chitwoodi, M. graminicola, M. graminis, M. microtyla, and M. naasi - each represented by a single population) were not closely related to each other or to the mitotic species.     

The More the Merrier: Recent Hybridization and Polyploidy in Cardamine

This article describes the use of cytogenomic and molecular approaches to explore the origin and evolution of Cardamine schulzii, a textbook example of a recent allopolyploid, in its ∼110-year history of human-induced hybridization and allopolyploidy in the Swiss Alps. Triploids are typically viewed as bridges between diploids and tetraploids but rarely as parental genomes of high-level hybrids and polyploids. The genome of the triploid semifertile hybrid Cardamine × insueta (2n = 24, RRA) was shown to combine the parental genomes of two diploid (2n = 2x = 16) species, Cardamine amara (AA) and Cardamine rivularis (RR). These parental genomes have remained structurally stable within the triploid genome over the >100 years since its origin. Furthermore, we provide compelling evidence that the alleged recent polyploid C. schulzii is not an autohexaploid derivative of C. × insueta. Instead, at least two hybridization events involving C. × insueta and the hypotetraploid Cardamine pratensis (PPPP, 2n = 4x−2 = 30) have resulted in the origin of the trigenomic hypopentaploid (2n = 5x−2 = 38, PPRRA) and hypohexaploid (2n = 6x−2 = 46, PPPPRA). These data show that the semifertile triploid hybrid can promote a merger of three different genomes and demonstrate how important it is to reexamine the routinely repeated textbook examples using modern techniques.     

Chromosome number, male meiosis and pollen fertility in selected angiosperms of the cold deserts of Lahaul-Spiti and adjoining areas (Himachal Pradesh, India)

In this study the exact chromosome number, detailed meiotic behavior in pollen mother cells and pollen viability were investigated, which can contribute to a better understanding of the cytological evolution of the species growing in the cold deserts of Lahaul-Spiti (Himachal Pradesh, India). This study is the first such comprehensive attempt to explore the region chromosomally. Chromosome number, meiotic behavior and pollen fertility were analyzed in 301 accessions of 140 species of Polypetalae. Chromosome counts in 14 species are the first ever records, viz., Aquilegia pubiflora (n?=?7), Corydalis govaniana (n?=?8), C. thyrsiflora (n?=?8), Hedysarum astragaloides (n?=?7), H. microcalyx (n?=?7), Oxytropis thomsoni (n?=?8), Rhodiola tibetica (n?=?10), R. wallichianum (n?=?16), Rosularia alpestris (n?=?14), Epilobium chitralense (n?=?18), E. leiospermum (n?=?18), Heracleum brunonis (2n?=?33), H. thomsonii (n?=?11) and Pleurospermum govanianum (n?=?9). New intraspecific diploid or polyploid cytotypes have been recorded in 13 species. The species of these cold deserts are quite active in evolution, depicting heterogeneity in chromosome number involving polyploidy, 51 species (36.43%) and/or aneuploidy (37 species). Various meiotic abnormalities were observed in the majority of the species, causing pollen sterility and pollen grains of variable sizes. We are of the opinion that harsh climatic conditions have caused various meiotic abnormalities in the majority of the plants, which has affected the genetic constitution and viability of male gametes.     

Chromosome number and secondary chromosomal associations in wild populations of Geranium pratense L. from the cold deserts of Lahaul-Spiti (India)

In this work we studied the meiotic chromosome number and details of secondary chromosomal associations recorded for the first time in Geranium pratense L. from the alpine environments in the cold deserts of Lahaul-Spiti (India). All the presently studied individuals of the species existed at 4x level (x = 14). The present chromosome count of n = 28 in the species adds a new cytotype to the already existing diploid chromosome count of 2n = 28 from the Eastern Himalayas and outside of India. Out of the six accessions scored presently four showed normal meiotic course. However, two accessions investigated from Mud, 3800 m and Koksar, 3140 m depicted abnormal meiotic course due to the presence of multivalents and univalents, and secondary associations of bivalents/chromosomes. The secondary chromosomal associations in the species existed among bivalents/chromosomes were noticed in the PMCs at prophase-I (diakinesis) and persisted till the separation of sister chromatids at M-II. The variation in the number of bivalents/chromosomes involved in the secondary associations at M-I (2–8) and A-I/M-II (2–12) has also been recorded. The occurrence of such secondary associations of bivalents/chromosomes in G. pratense which existed at 4x level indicated the secondary polyploid nature of the species.     

Cytomorphological diversity in some selected members of Poaceae from Parvati Valley in Kullu district of Himachal Pradesh,India

The present work includes detailed male meiotic studies on 46 species of grasses falling into 59 accessions from different localities of Parvati Valley in Kullu district of Himachal Pradesh in the altitudinal range of 1,100 to 2,750 m. All the species have been studied cytologically for the first time from the study area. The meiotic chromosome count of n = 14 for Calamagrostis emodensis is the first ever chromosome report. Three species, namely Agrostis alba (n = 21), Avena byzantina (n = 21) and Bromus inermis (n = 14) have been studied cytologically for the first time from India. New intraspecific diploid/polyploid cytotypes have been reported for Arthraxon serrulatus (2n = 4x = 32), Iseilema laxum (2n = 12x = 60), Digitaria albudens (2n = 8x = 72), Festuca kashmiriana (2n = 2x = 14) and Stipa orientalis (2n = 2x = 20). The existence of variable number of B-chromosomes (2n = 60 + 0-5B) has been reported for the first time in the 12x cytotype of Iseilema laxum. Secondary associations of chromosomes in the tetraploid cytotype of Cymbopogon martini (n = 20) indicated its secondary polyploid nature. As many as 18 species showed various meiotic anomalies such as the phenomenon of cytomixis involving inter PMC migration of chromatin material, chromatin stickiness, interbivalent connections, abnormal spindle activity, presence of bridges and laggards during anaphases and telophases and abnormal sporads. These meiotic abnormalities consequently yielded sterile and heterogeneous-sized fertile pollen grains. The polyploidy and aneuploidy have played an active role in the evolution of grasses.