The International Journal of Plant Reproductive Biology
(Indexed by CABI)
ISSN Print : 0975-4296; ISSN Online : 2249-7390
 
Volume-2, Number-2, June  2010
 

Species Concepts and Definitions: Reproductive Isolation as a Tool to
Reveal Species Boundaries

Alberto Amato
ENS/CNRS UMR8197 IBENS, Génomique Environnementale et Evolutive, 46, rue d’Ulm 75230 Paris CEDEX05, France.
e-mail: amato@biologie.ens.fr

  ABSTRACT

Species are the smallest taxonomical units and the description and recognition of such entities has been long debated. For protists and especially for diatoms, species recognition has been historically based on morphology but thanks to the introduction of phylogeny in this group of organisms, it emerged that genetic difference was much higher than morphological variability. This led to the introduction of the concept of cryptic species. In the present paper I compare nine species concepts, their strength and weaknesses (with special emphasis on the biological species concept), and link it with species boundary recognition in protists.

Keywords : Cryptic diversity, diatoms, protists, species concept, species definition, species recognition

 

Biodiversity Analysis and Reproductive/Cultural Behaviour of Cyanobacteria of North
East Region of India having Acidic Properties

S. Deepa Devi, Thingujam Indrama and O.N. Tiwari*
Microbial Bioprospecting Laboratory, Microbial Resources Division, Institute of Bioresources and Sustainable
Development, Takyelpat, Imphal - 795 001, Manipur

*
e-mail: ontiwari1@rediffmail.com

  ABSTRACT

During the course of intensive survey made in different parts of North-East India four hundred fifty two acid tolerant (5.0 to 6.5 pH) accessions of cyanobacteria belonging to twenty eight genera have been collected from eight states (Manipur-285, Meghalaya-56, Tripura-20, Assam-26, Sikkim-23, Arunachal Pradesh-12, Mizoram-04 and Nagaland-26). They are being maintained as unialgal culture and deposited in freshwater cyanobacterial repository created by Department of Biotechnology, Government of India at Institute of Bioresources and Sustainable Development, Imphal, Manipur. One hundred isolates belonging to 15 genera and 50 species have been identified by conventional methods. Present paper deals with the morphological and reproductive behaviour of these.

Keywords : Acid tolerant cyanobacteria, cultural studies, North-East Region, India

 
 

Life Cycle of Rozella allomycis Foust an Obligate Parasite on Allomyces arbuscula Butler

S.K. Prabhuji* , Neetu Sharma , Ashutosh Tripathi , Richa Srivastava, Anurag Rai & Samarjeet Saini
Biotechnology and Molecular Biology Centre, M.G. Postgraduate College, Gorakhpur – 273 001, India
Department of Biotechnology, Bundelkhand University, Jhansi – 284 128, India
Department of Pathology, Pacific College of Physiotherapy, Gorakhpur – 273 015, India
Department of Biotechnology, AAI-Deemed University Allahabad – 211 007, India

*
e-mail : shaktiprabhuji@rediffmail.com

  ABSTRACT

Life cycle of Rozella allomycis Foust a Chytrid parasite, on the hyphal segments of Allomyces arbuscula Butler. Was studied. Rozella allomycis was found to trans-parasitize, in vitro, on an isolate of Allomyces sp. (Isolate B-1201).

Keywords : Chytrid, Rozella allomycis, Allomyces arbuscula, host specificity, trans-parasitize.

 

Effect of Some Physical Factors on Reproductive Behaviour of Selected Bryophytes

Vishal Awasthi, Virendra Nath* & A.K. Asthana
Bryology Laboratory, National Botanical Research Institute
(Council of Scientific & Industrial Research, New Delhi), Lucknow – 226 001, India
*e-mail : drvirendranath2001@rediffmail.com

  ABSTRACT

In vitro studies have been carried out on twelve bryophyte taxa: Funaria hygrometrica Hedw., Bryum coronatum Schwaegr., Bryum capillare L. ex Hedw., Bryum bicolor Dicks., Hyophila involuta (Hook.) Jaeg., Bryoerythrophyllum recurvirostrum (Hedw.) Chen., Hydrogonium arcuatum (Griff.) Wijk et Marg., Marchantia paleacea Bertol., Lunularia cruciata (L.) Dum., Plagiochasma appendiculatum Lehm. et Lindenb., Asterella angusta (St.) Kachroo, Cryptomitrium himalayense Kash. under controlled conditions. Funaria hygrometrica Hedw. and Bryum coronatum Schwaegr. could produce gametangia after maturity only at 18-200C, while remaining others produced asexual propagules like gemmae, protonemal gemmae, rhizoidal gemmae, brood cells after maturity and particularly in dry culture conditions, low humidity and warm temperature + 250C. This production of asexual propagules seems to be compensation for failure of sexual reproduction in varying environmental conditions.

Keywords : Asexual propagules, bryophytes, gemmae, reproduction.

 
 

Density Effect in the Gametophyte Development of a Xerophilous Fern Species,
Cheilanthes hispanica Mett.

Sara García-Gómez, Emilia Pangua and Santiago Pajarón
Departamento de Biología Vegetal I, Facultad de Biología, Universidad Complutense, E-28040 Madrid, Spain

*
e-mail : spajbot@bio.ucm.es

  ABSTRACT

The gametophyte or prothallium is the sexual phase of the leptosporangiate ferns. Potentially it can produce antheridia and archegonia, but there are several environmental factors that may influence the development of one or other of the gametangia, especially those that affect prothallium growth. One of these factors is population density. In this research we studied the effect of different densities over the development of Cheilanthes hispanica Mett., a xerophilous fern of the western Mediterranean basin. The experiment used densities varying from one prothallium per cm2 to eight prothalli per cm2. Samples were made at four, eight and twelve weeks. Density affected gametophyte growth only after 12 weeks. And sexual expression was only affected at the beginning of the experiment in the first sampling after only four weeks. Production of vegetative proliferations by the gametophytes was detected, and there was a relationship between them and the development of antheridia.

Keywords : Antheridia, archegonia, prothallium growth, sexual expression, Monilophytes

 
 

Heteromorphic Incompatibility and Disassortive Mating in a Distylous Critically Endangered Alpine Herb Arnebia benthamii (Wall ex G Don) I.M. Johnston (Boraginaceae)

Khursheed A Ganaie* & Shabana Aslamb
Department of Botany, Islamia College of Science and Commerce, Hawal Srinagar J&K India
Department of Botany, University of Kashmir, J&K India
*e-mail : khursheedtrali@yahoo.co.in

  ABSTRACT

Arnebia benthamii is a critically endangered perennial herb endemic to alpine regions of N.W.Himalaya. The species exhibits tremendous medicinal potential and is used by the locals and tribals of Jammu and Kashmir to cure many ailments. The reproductive biology and breeding system of the species was investigated in the wild and in an experimental population established in the Botanical Garden of Kashmir University. The pollen mother cell meiosis showed that the species is diploid having 2n=2x=14.This is the first report of chromosome enumeration for the species from Kashmir Himalayas. Field observations confirmed that the species is heterostylous with stigma and anthers exhibiting reciprocal positions in the two morphs. This reciprocal herkogamy is associated with ancillary polymorphism involving pollen size and stigma papillae length. Crossing experiments demonstrated that the syndrome of heterostyly is associated with heteromorphic sporophytic incompatibility. In pinpin intramorph crosses pollen tube progression is inhibited in the style; however, in thrum intramorph crosses stigma is the major site of tube inhibition. Only intermorph crosses result in normal tube progression, fertilization and seed set. This syndrome of heterostyly and incompatibility manifests in absolute xenogamy, disassortive mating and Isoplethy-1:1 morph ratio at equilibrium. The species shows negative frequency dependant reproductive success and bumble bees render the service of pollen transport with maximum legitimacy.

Keywords : Heterostyly, Isoplethy, Mating pattern, Xenogamy

 
 

Reproductive effort in two populations of Murdannia nudiflora (L.) Brenan.

Raman Kumar* and Veenu Kaul
Department of Botany, University of Jammu, Jammu - 180 006 (J&K)

*
e-mail : ramankumar1313@gmail.com

  ABSTRACT

Two populations of M. nudiflora (L.) Brenan identified were designated as undisturbed and disturbed because of stress they faced. Plants of both the populations showed lot of variation in their vegetative parameters as compared to the reproductive ones. Plants of undisturbed populations were tall and hardy, and those of disturbed, dwarf and stunted. Variation in plant height and leaf number led to differences in biomass allocation to these organs. These, in turn, reflect the variation in reproductive effort from plant to plant within each population. Overall, reproductive effort did not vary significantly among the populations and seemed to bear no relation with stress.

Keywords : Murdannia nudiflora, reproductive effort, stress, biomass allocation

 
 

Nectar Sugar Composition and Pollinators for the Naturalized Exotic Leonurus japonicus (Lamiaceae) in Central Argentina

Leonardo Galetto* & Carolina Torres
Instituto Multidisciplinario de Biologia Vegetal (UNC-CONICET), Casilla de Correo 495, 5000 Córdoba,
Argentina. Cátedra de Diversidad Vegetal II, Facultad de Ciencias Exactas, Físicas y Naturales,
Universidad Nacional de Córdoba, Argentina.

*
e-mail : leo@imbiv.unc.edu.ar

  ABSTRACT

Volumes of nectar and sugar concentration were measured in different populations of the naturalized exotic Leonurus japonicus Houtt. (Lamiacaea) in central Argentina. Qualitative and quantitative nectar sugar composition were determined and compared between populations. In general, nectar sugar concentration was high and volume per flower was very low for all populations. Nectar sugars were glucose, fructose and sucrose for all populations, but sucrose clearly predominates over hexoses. Honeybees and bumblebees were recorded as the main pollinators in this region. Bumblebees preferences for sucrose-high nectars can be indicating that this exotic species can attract these pollinators and assure seed production to expand their populations. On the other hand, honeybees can use this nectar resource because they are generalist and have enzymes to break the sucrose in hexoses. New interesting studies can be settled considering the invasion process as theoretical framework, and developing field experiments to link plant reproductive biology, nectar traits and pollinator preferences.

Keywords : Nectar sugar composition, bumblebees, honeybees, pollinator preferences

 
 

Microsporogenesis and Male Gametogenesis in Some Species of Jatropha L. (Euphorbiaceae)

Divya Sharma* and Anita Rana
Department of Botany, School of Life Sciences, Dr. B.R. Ambedkar University, Agra-282002, India

*
e-mail : divyasharma_agra@yahoo.co.in

  ABSTRACT

The anther development, microsporogenesis and male gametogenesis in four Jatropha species namely J. integerrima L., J. curcas L., J. gossypifolia L. and J. podagrica L. were studied. The development in all the species is more or less similar and the anther wall development is of the dicotyledonous type, and wall is composed of an epidermis, endothecium, middle layers and glandular tapetum. The cytokinesis following meiosis is simultaneous, producing tetrahedral tetrads. Mature pollen grains are two-celled at anthesis, with a spindle shaped generative cell. A few abnormal microspores were observed following the early stages of microgametophyte development.

Keywords : Jatropha, male gametogenesis, microsporogenesis.

 
 

Phenology and Reproductive Biology of Caesalpinia bonducella (L.) Flem. (Fabaceae)

Richa Singh & Seema Chauhan*
Department of Botany, School of Life Science, Dr. B.R. Ambedkar University, Agra – 282 002, India

*e-mail : carclubagra@gmail.com

  ABSTRACT

Caesalpinia bonducella (L.) Flem. (Fabaceae) is a vigorous scrambling bushy shrub with considerable medicinal importance worldwide. In this paper, we investigated the phenology and reproductive biology of this species. Observations were recorded from August/2009 to July/2010 in the gardens on five plants at each of five different sites of Agra district. Leaf–fall and leaf–renewal more or less occurs throughout the year. Flowering starts in mid August and continues till the second week of April. Maximum flowering takes place between last week of August to September, while it is moderate between January to mid April. During the period between last week of April to first week of August the plant is without flowers. Fruiting was initiated at the end of August and continues till the end of September. Flowers are yellow, hermaphrodite, zygomorphic, complete and polypetalous. Anthesis occurs between 0400–0530 hrs. There are ten stamens arranged in two whorls of five each, yellowish green, polyandrous and they dehisce longitudinally between 0700–1000 h. Pollen grains are spheroidal, tricolpate and tricolporate and 45±4 μm in diameter. Stigma becomes receptive between 0930–1100 h. The plants exhibited considerable variation in pollen fertility caused by the change in temperature. Large number of unicellular trichomes were observed on calyx, corolla, anther filament and style.There are 12480 pollen/flower and 2 ovules/flower. Pollen-ovule ratio is 6240: 1. Apis indica and Apis dorsata, butterflies (Pieris spp. and Limenistis sp.), bumble bee (Xylocopa sp.) were the effective pollinators. Wasps were occasional pollinator. Large black ants also visit flowers for steeling honey.Failure of fruit set after hand self-pollination indicated that C. bonducella is self-incompatible. Natural fruit set was low (16.5%) with two seeds/fruit (100%). The high pollen-ovule-ratio and hand pollination  experiments suggested that this species is obligate xenogamous.

Keywords : Caesalpinia bonducella (L.) Flem., floral biology and pollination biology, obligate xenogamy

 

 
 

Stigma surface manifestations of self-incompatibility in Kopsia fruticosa A.DC. (Apocynaceae)

P.M. Radhamany & Sheeja Purushothaman
Department of Botany, University of Kerala, Thiruvananthapuram, Kerala – 695581, India

e-mail : radhamany_m@rediffmail.com

  ABSTRACT

Kopsia fruticosa A.DC. belonging to the family Apocynaceae, is a perennial shrub producing large number of pink flowers throughout the year. It rarely produces fruits which are mostly without out viable seeds. In order to understand the causes of failure of seed -set in this plant, various aspects of pollen-pistil interactions were studied. Pollen viability was assessed by in vitro pollen germination in Brewbacker & Kwack’s medium supplemented with different concentrations of sucrose. In vegetatively propagated K. fruticosa, highest pollen germination percentage (50.2) was observed in medium supplemented with 20% sucrose. Flurochromatic reaction test showed 45% viable pollen grains. In vivo pollen germination was done using decolorized aniline blue staining method. There were no significant variation in the pollen germination between open and self-pollinated flowers after 24 and 48h of flower opening. None of the pollen tubes penetrated into the stigma and pollen tubes showed various abnormalities such as curling of tubes, multiple tubes, irregular callose deposition and bulging of pollen tube tip. It is concluded that in K. fruticosa incompatible pollination may cause some physiological or biochemical changes which leads to pollen tubegrowth inhibition on the surface of the stigma and lack of seed-set in this plant.

Keywords : Callose, FCR test, pollen germination, pollen-pistil interaction

 

 
  Floral Biology and Pollination Biology of Cannabis sativa L.

Anita Rana* and Namrta Choudhary
Department of Botany, School of Life Sciences, Khandari Campus, Dr. B.R. Ambedkar University,
Agra – 282 002, India

*e-mail : anita_rana21@rediffmial.com

  ABSTRACT

Cannabis sativa L. (Cannabiaceae) commonly known as marijuana is dioecious. Maximum floral density was observed in the month of April– une in male plants and May–June in female plants. Male flowers are borne on loose panicle and yellowish green in colour, while female flower are greenish white and arranged in axillary crowded spikes. The anthesis of male flower occurs between the 1000–1100 h in February–March and anthers dehisce between 1100–1140h, while during the months between April–October, anthesis take place between 0800–0845 h and anthers dehisce between 0845– 0915 h. The anthesis of female flowers occurs between the 1030–1100 h during February– March and stigma becomes receptive between 1100–1230 h. In months of April–November anthesis takes place between 0830–0900 h followed by stigmatic receptivity between 0900–1000 h. Pollen viability was highest in the month of April. Unicellular trichomes were seen on the dorsal and ventral surface of tepals and ovarian surface. Pollen grains are 30 μm in diameter and are triporate and suboblate. Number of pollen/flower 36,553 + 8.07 and number of pollen/anther is 7,256 + 9.86. There is one ovule per ovary and pollen ovule ratio is 36,553: 1. Pollination is anemophilous and fruit-set percentage is 16.6% and seed-set is 100%.

Keywords : Cannabis sativa L. floral biology, pollination biology.

 

 
  Pollen-Pistil Interaction in Two North-Eastern Himalayan Tree Species: Schima wallichii (DC.)
Korth. and Schima khasiana Dyer (Theaceae)
Sanjiban Goswami & Arun K. Pandey*
Department of Botany, St. Edmunds College, Shillong 793003, Meghalaya, India
Department of Botany, University of Delhi, Delhi 110007

e-mail :arunkpandey@hotmail.com
  ABSTRACT

Pollen-pistil interaction in Schima wallichii (DC.) Korth. and S. khasiana (Dyer) Bloemb. (family Theaceae) has been studied. In S. khasiana anthesis takes place at 0300 h whereas in S. wallichii it takes place at 0400 h.. Pollination is entomophilous. The stigma is of Wet type. The stigmatic exudates appear as a glistening drop on stigma surface. In S. wallichii and S. khasiana the stigmas become wet after 8 h and 10 h after anthesis respectively. In S. wallichii the pollen tubes emerge within 3 h after pollination whereas in S. khasiana pollen tubes emerge after 6 h after pollination. Callose plugs are formed at irregular intervals in the pollen tubes all along the length of style. The first few pollen tubes were observed to reach the embryo sacs 96 h after pollination. The fluorescence test shows that the receptive synergid fluoresces more brightly and fertilization occurs when the pollen tube tip fuses with the fluorescing synergid.

Keywords : Schima, Theaceae, pollen-pistil interaction

 

 
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