Development of the Anther and Ovule in Capsicum L

Abstract

The structure of the anther and ovule and the development of the male and female gametophytes have been studied in seven cultivated varieties of Capsicum-C. annuum L. var. acuminatum Fingerh. (long red cayenne), C. annuum L. cv. Floral Gem, C. annuum L, var. grossum (L.) Sendt. (giant bell), C. annuum var. longum (DC.) Sendt. (long sweet yellow), C. baccatum L. var. pendulum (Willd.) Eshbaugh, C. frutescens L, var. baccatum (L.) Irish and C. frutescens L, cv. Tabasco. Marked differences in the development were observed between flower buds formed in summer and in winter. In the anthers of winter flower buds of C. annuum var, acuminatum the pollen grains show nuclear multiplication and pollens with all nuclear numbers between two and eight are represented. However, 'pollen embryo sacs' as such are not formed. The normal viable pollen grains are binucleate. The pollen fertility in summer is 93.6% while in winter, on the same plants, it is only 31.3 %. In the development of the ovule there are no marked differences amongst the varieties except in size. Coexistence of mono-, bi- and tetrasporic embryo sac developments has been found in C. annuum var. acuminatum in which monospory is dominant in summer but bispory in winter. Monosporic and bisporic embryo sacs coexist in C. baccatum var. pendulum and C. frutescens var. baccatum. The other varieties show only monosporic development.

Reproductive development and nuclear DNA content in angiosperms

“…(2) Variation in megasporogenesis has been related to growth under uncertain environmental conditions (e.g., Donoghue and Scheiner, 1992). Wall formation during megasporogenesis is affected by temperature and environmental variation (e.g., Hjelmqvist andGrazi, 1964, 1965;Dharmadhaj and Prakash, 1978). Correspondingly, the microtubular system of the reproductive plant cell is relatively sensitive to temperature and other environmental conditions (Sax, 1937;Brown and Lemmon, 1991;Zaki and Dickinson, 1991).…”

Meiotic irregularities in Capsicum L. species

“…In C. chinense, PV percentages were between 84 to 87 %, being 60 % from unviable PG, type T1, however, multivalents were observed during the chromosome pairing (Lanteri and Pickersgill 1993). Dharamadhaj and Prakash (1978) attributed the variation found in the PV percentage in Capsicum species to environmental influence and observed pollen fertility above 90 % in the summer, while in the winter the same accessions presented a maximum pollen fertility of 31 %.…”

Development of the gametophytes, flower, and floral vasculature in Dichorisandra thyrsiflora (Commelinaceae)

“…Attributing taxonomic significance to the variation between monosporic, bisporic, and tetrasporic types known within the family should be cautioned. The findings of Hjelmqvist and Grazi (1965) and Dharamadhaj and Prakash (1978) in certain non-commelinaceous taxa indicate that environmental factors such as temperature may influence modes of development.…”

“…The Allium type (Davis, 1966) and Adoxa type (McCollum, 1939;Stevenson and Owens, 1978) have also been reported in the family. The findings of Hjelmqvist and Grazi (1965) and Dharamadhaj and Prakash (1978) in certain non-commelinaceous taxa indicate that environmental factors such as temperature may influence modes of development. This is indicative of a master control over final megagametophyte structure that is to some degree independent of the number of megaspores contributing to its formation.…”