The effects of methionine and cobalt ions on sex expression and development of Anemia phyllitidis gametophytes

Background: The metal ions play a vital role in a large number of widely differing biological processes. Some of these processes are quite specific in their metal ion requirements. In that only certain metal ions, in specific oxidation states, can full fill the necessary catalytic or structural requirement, while other processes are much less specific. Objective: In this paper we report the binding of Mn (II), Ni (II) and Co (II) with albumin are reported employing spectrophotometric and pH metric method. In order to distinguish between ionic and colloidal linking, the binding of metal by using pH metric and viscometric methods and the result are discussed in terms of electrovalent and coordinate bonding. Methods: The binding of Ni+2, Co+2 and Mn+2 ions have been studied with egg protein at different pH values and temperatures by the spectrometric technique. Results: The binding data were found to be pH and temperature dependent. The intrinsic association constants (k) and the number of binding sites (n) were calculated from Scatchard plots and found to be at the maximum at lower pH and at lower temperatures. Therefore, a lower temperature and lower pH offered more sites in the protein molecule for interaction with these metal ions. Statistical effects seem to be more significant at lower Ni+2, Co+2 and Mn+2 ions concentrations, while at higher concentrations electrostatic effects and heterogeneity of sites are more significant. Conclusion: The pH metric as well as viscometric data provided sufficient evidence about the linking of cobalt, nickel and manganese ions with the nitrogen groups of albumin. From the nature and height of curves in the three cases it may be concluded that nickel ions bound strongly while the cobalt ions bound weakly.

Download Full-text

Architecture and Gender Allocation: Floral Sex Expression Along Branches of the Monoecious cucurbit, Apodanthera undulata

International Journal of Plant Sciences ◽

10.1086/297012 ◽

1992 ◽

Vol 153 (1) ◽

pp. 108-116 ◽

Cited By ~ 11

Author(s):

Veronique A. Delesalle

Keyword(s):

Sex Expression ◽

And Gender

Download Full-text

A Quantitative Genetic Analysis of Nuclear-Cytoplasmic Male Sterility in Structured Populations of Silene vulgaris

Genetics ◽

10.1093/genetics/158.2.833 ◽

2001 ◽

Vol 158 (2) ◽

pp. 833-841 ◽

Cited By ~ 2

Author(s):

Douglas R Taylor ◽

Matthew S Olson ◽

David E McCauley

Keyword(s):

Population Structure ◽

Sex Ratio ◽

Genetic Analysis ◽

Cytoplasmic Male Sterility ◽

Male Sterility ◽

Sex Expression ◽

Silene Vulgaris ◽

Population Variance ◽

Quantitative Genetic ◽

Quantitative Genetic Analysis

Abstract Gynodioecy, the coexistence of functionally female and hermaphroditic morphs within plant populations, often has a complicated genetic basis involving several cytoplasmic male-sterility factors and nuclear restorers. This complexity has made it difficult to study the genetics and evolution of gynodioecy in natural populations. We use a quantitative genetic analysis of crosses within and among populations of Silene vulgaris to partition genetic variance for sex expression into nuclear and cytoplasmic components. We also use mitochondrial markers to determine whether cytoplasmic effects on sex expression can be traced to mitochondrial variance. Cytoplasmic variation and epistatic interactions between nuclear and cytoplasmic loci accounted for a significant portion of the variation in sex expression among the crosses. Source population also accounted for a significant portion of the sex ratio variation. Crosses among populations greatly enhanced the dam (cytoplasmic) effect, indicating that most among-population variance was at cytoplasmic loci. This is supported by the large among-population variance in the frequency of mitochondrial haplotypes, which also accounted for a significant portion of the sex ratio variance in our data. We discuss the similarities between the population structure we observed at loci that influence sex expression and previous work on putatively neutral loci, as well as the implications this has for what mechanisms may create and maintain population structure at loci that are influenced by natural selection.

Download Full-text

Probing the floral developmental stages, bisexuality and sex reversions in castor (Ricinus communis L.)

Scientific Reports ◽

10.1038/s41598-021-81781-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sujatha Thankeswaran Parvathy ◽

Amala Joseph Prabakaran ◽

Thadakamalla Jayakrishna

Keyword(s):

Developmental Stages ◽

Ricinus Communis ◽

Sex Expression ◽

Pistil Abortion ◽

Ricinus Communis L ◽

Sex Reversion ◽

Stage 4 ◽

Meristem Development ◽

Male Specific ◽

First Time

AbstractCastor (Ricinus communis L) is an ideal model species for sex mechanism studies in monoecious angiosperms, due to wide variations in sex expression. Sex reversion to monoecy in pistillate lines, along with labile sex expression, negatively influences hybrid seed purity. The study focuses on understanding the mechanisms of unisexual flower development, sex reversions and sex variations in castor, using various genotypes with distinct sex expression pattern. Male and female flowers had 8 and 12 developmental stages respectively, were morphologically similar till stage 4, with an intermediate bisexual state and were intermediate between type 1 and type 2 flowers. Pistil abortion was earlier than stamen inhibition. Sex alterations occurred at floral and inflorescence level. While sex-reversion was unidirectional towards maleness via bisexual stage, at high day temperatures (Tmax > 38 °C), femaleness was restored with subsequent drop in temperatures. Temperature existing for 2–3 weeks during floral meristem development, influences sexuality of the flower. We report for first time that unisexuality is preceded by bisexuality in castor flowers which alters with genotype and temperature, and sex reversions as well as high sexual polymorphisms in castor are due to alterations in floral developmental pathways. Differentially expressed (male-abundant or male-specific) genes Short chain dehydrogenase reductase 2a (SDR) and WUSCHEL are possibly involved in sex determination of castor.

Download Full-text