• S S Bir

      Articles written in Proceedings – Plant Sciences

    • Cytological studies on certain Acanthaceae from Central India

      M I S Saggoo S S Bir

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      Cytological studies have been made on 19 species of Acanthaceae from Pachmarhi hills in Central India. Present studies reveal the first count of chromosome numbers for four species, namely,Dyschoriste depressa Nees,n=30;Lepidagathis fasciculata Nees,n=10;L. hyalina Nees,n=10 andJusticia diffusa Willd. var.prostrata Roxb.,n=9. New cytotypes have been located in three species asHemigraphis latebrosa Nees,n=28 (4x);Rungia parviflora Nees,n=13 (2x) andR. pectinata Nees,n=13 (2x). Diploid cytotypes of three species,viz., Blepharis maderaspatensis (Linn.) Roth,n=15;Justicia betonica Linn.,n=17 andThunbergia alata Bojer ex. Sims,n=9 have been detected for the first time from India. An analysis of the worked out species reveals the existence of only 10·53% polyploid species.

    • Cytopalynology of some members of Rutaceae

      V K Singhal B S Gill S S Bir

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      Cytopalynology of 13 species of the family Rutaceae from North and Central India do not reveal any correlation between polyploidy and pollen size. Partial pollen malformation in certain species does not seem to be due to detectable cytological reasons. Multivalent formation in some trees ofCitrus jambhiri (2n=18) is due to reciprocal translocations. The newly counted species,C. jambhiri (2n=18) and the monotypic genusLimonia (L. crenulata,n=9) and all other species except forZanthoxylum armatum (n=33) are based onx=9. Though the family is polybasic,x=9 appear to be its original based number. The chromosomal heterogeneity in the family (2n=14–162) coupled with dysploid series of base numbers (x=7–19) confirm that polyploidy and aneuploidy have played a considerable role in speciation.

    • Cytology of woody species

      V K Singhal B S Gill S S Bir

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      Cytological studies have been made on 59 woody species of Polypetalae. Two genera (Gynocardia odorata,n=23;Pahudia martabanica,n=12) and 9 species (Talauma candollei,n=19;Cratoxylon polyanthum,n=11;Sterculia villosa,n=20;Grewia hirsuta,n=9;Millettia brandisiana, 2n=22+0−2B;Phanera glauca,n=14;Terminalia oliveri,n=12;Psidium coriaceum, 2n=77;P. pumilum,n=11) are counted for the first time. Additional and/or varied chromosome numbers are recorded for 8 species. Presence ofB-Chromosomes has been detected inCrataeva nurvala (n=13+0−3B),Erythrina caffra (n=21+0−3B) andMillettia brandisiana (2n=22+0−2B). Existence of some multivalents in the tetraploid taxa ofEugenia jambolana (2n=44) andHydnocarpus laurifolia (2n=48) indicates their segmental alloploid nature. But the presence of cent per cent trivalents (11III) in the triploid cytotype ofEugenia uniflora (2n=33) reveals the autotriploid nature. Presence of some univalents in diploid taxa ofMillettia brandisiana (2n=22) may be due to asynapsis and/or desynapsis. Variation in chromosome number inPMCs and some pollen sterility inHydnocarpus kurzii seems to be the consequence of cytomixis. Abnormalities in microsporogenesis in one of the cultivated trees ofFirmiana pallens (2n=40) are due to spindle irregularities.

    • Cytological studies on members of family Labiatae from Kodaikanal and adjoining areas (South India)

      S S Bir M I S Saggoo

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      Chromosomal analysis of 33 species of Labiatae from South India have indicated that 23·53% are polyploids. Several taxa are investigated for the first time. Analysis of results in totality for the region indicates that shrubby and perennial species have higher incidence of polyploidy. Polybasic nature of the family as well as the investigated taxa is quite apparent and this indicates the role of eu- and aneuploidy in evolution of various taxa in the family.

    • Cytology and distribution pattern of woody species of Verbenaceae in Palni hills

      G S Chatha S S Bir

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      Studies on the cytology and distribution pattern of 16 woody species of Verbenaceae from Palni hills have shown that: (i) in case ofLantana, the chromosome size is not influenced by increase or decrease in chromosome numbers, (ii) there is no correlation of chromosome size with the habits of different species ofVitex, (iii) transmigration of chromatin material inGmelina arborea, Lantana aculeata andSymphorema polyandrum results in encoutering of abnormal chromosome numbers, (iv) inLantana camara loose or compact association of various groups of chromosomes indicates that genomic constitution of the species is made up of intermingling of different genomes, (v)L.camara (4x) andL. indica (6x) do show the presence of multiple associations in some pollen mother cells which indicate their autoalloploid nature, and (vi) inNyctanthes arbortristis, the correct recorded number is 18 bivalents and the earlier reports of n=22 and n=24 cannot be explained easily.

      The distribution pattern of various species in Palni hills as worked out here shows that in case of theLantana, tetraploid species have widers range of distribution as compared to 2x and 6x ones. The maximum representation of the presently studied species is between 900–1400 m altitudinal zone illustrating that each species is represented in more than one type of forests while overlapping of distribution in different forests is not a rare phenomenon of the investigated taxa.

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