Variegation in Four O’clock Plant

-




 In Mirabilis jalapa (four o’clock plant), the leaves on certain branches of a plant may be fully green; other branches have patchy leaves in which green tissue is interspersed with pale- green to white tissue in a variegated pattern; and other branches bear fully pale leaves.


Microscopic examination of the green leaves and the green areas of the variegated leaves reveals that the cells contain normal chloroplas­tids and chlorophyll pigment, whereas the pale- leaves and pale patches lack normal chloroplas­tids and pigment. When the inheritance of these pigment traits is examined, it is found that the phenotype of the progeny will depend upon phenotype of the female parent (Figs. 10.2, 10.3).



Ovules derived from fully green portions of the plant, regardless of the source of pollen, will result only fully green plants and variegated character will not reappear in the subsequent generations.

When ovules are derived from variegated branches, three types of seeds are produced in variable numbers, again regardless of the male parent; some give rise to (sure green, some to pure white, and the majority to variegated offspring’s. Ovules derived from pale branches, will result only pale plants.



Comments

Post a Comment

Popular posts from this blog

MODE OF REPRODUCTION IN FUNGI (PART-2) Asexual Reproduction

-
Image
 1. Asexual Reproduction The reproduction by spores, is called asexual reproduction . The spores are minute cells that serve as reproductive propagules. Spore production is the most common method of reproduction in fungi. There are four types of asexual spores. They are: 1. Conidia 2. Sporangiospores (Endospores) 3. Chlamydospores 4. Arthospores 1. Conidia (singular-Conidium) a. Conidium is a spore formed freely at the tip or side of hypha.  b. Specialized hyphae having such spores are called conidiophores .  c. The tip of conidiophore swells out and produces a spe-cial cell called sterigma (Plural., Sterigmata).  d. The tip of sterigmata cuts off rounded cells called conidia one by one.  e. The conidia germinate and give rise to new mycelia 2. Sporangiospore a. Sp orangiospore or endospore is a spore formed within a sporangium (plural.,sporangia).  b . A sporangium is a sac-like structure within which asexual spores are produced Specialized hyphae havi...
Read more

MODE OF REPRODUCTION IN FUNGI (Part-3) Sexual Reproduction

-
Image
1. Sexual Reproduction a. The sexual reproduction involves the union of male and female gametes or two gametangia  b. It has three distinct phases. They are plasmogamy, karyogamy and meiosis. c. The plasmogamy refers to the fusion of two protoplasts that brings two haploid nucle together. d. As a result of plasmogamy a cell containing two haploid nuclei is formed.  e. This cell is known as binucleate cell or dikaryotic cell.  f. The two nuclei residing in that cell are known as a dikaryon.  g. Plasmogamy may be carried out either by gametic union or gametangial contact. h. The next phase is the karyogamy . During karyogamy the two haploid nuclei in a dikaryotic cell fuse together and form diploid nucleus (2N).  I. This nucleus is called a synkaryon . This phase lasts for a short time. It is also known as diplophase. j. Meiosis is the third phase in the sexual reproduction. The diploid nucleus undergoes re-duction division and gives rise to four haploid nucl...
Read more

Oedogonium Structure and Reproduction // Detailed Notes By Rohit Jirobe //

-
Image
Oedogonium Class : Chlorophyceae Order : Odogoniales Family : Odogoniaceae Genus : Oedogonium Oedogonium is a green alga. It is placed in the class Chlorophyceae. This genus was named by Link . Occurrence Oedogonium is widely distributed in freshwater habitats such as ponds, lakes, tanks, mers , etc. The mature filaments are free-floating but the younger ones are attached. They are found attached to stones, woods and to large algae and aquatic angiosperms . There are about 285 species in Oedogonium. Of these, 144 species are found in India . The common Indian species are: Oedogonium nodulosum ,  Oedogonium fragile ,  Oedogonium aquaticum ,  Oedogonium gracilius . Structure Oedogonium is a unbranched filamentous green alga. It is included in the class Chlorophyceae.  It is cosmopolitan in distribution. The plant is a haploid gametophyte . It is a freshwater alga. It is an attached form. It is a filamentous alga. The thallus consists of a long filament and a holdfast...
Read more