Types of ovules, Biology

Assignment Help:

Types of Ovules

Anatropous

This is the most common type of ovule in angiosperms in which the ovule undergoes curvature such that the micropylar end comes to lie parallel to the funiculus.

Orthotropous

In this type of ovule no curvature occurs and the micropyle lies in a straight line with respect to the funiculus.

Hemi anatropous

The hemi anatropous condition results from the curvature of the ovule such that the micropyle comes to lie at right angles to the funiculus.

Campylotropous

In campylotropous type, the ovule is curved but the curvature is less than that in the anatropous condition.

Amphitropous

The amphitropous ovule looks like the campylotropous ovule at the first glance. But there is a point of distinction. In this type the nucellus and the embryo sac are curved like a horse shoe.

Circinotropous

Besides the above basic forms, another interesting type that you should know is the circinotropous ovule. In the early developmental stages of such ovules the .nucellar protuberance is more or less in line with the axis. In the further developmental stages, due to unilateral growth, it assumes anatropous form. The curvature does not stop at this, but continues until the ovule has turned over completely so that the micropylar end again points upwards. This kind of ovule is common in families Cactaceae and Plumbaginaceae.


Related Discussions:- Types of ovules

Describe briefly about vitamin B2, Vitamin B 2 (Riboflavin) Riboflavin...

Vitamin B 2 (Riboflavin) Riboflavin is a yellow to orange-yellow, crystalline powder of faint odour and intensely bitter taste. Its solubility in water is very slight and depe

What is fixism, What is fixism? Fixism is the theory about the diversit...

What is fixism? Fixism is the theory about the diversity of life on earth that affirms that the current existent species were identical to species of the past and came out alre

Explain about the serengeti ecosystem, Explain about the Serengeti Ecosyste...

Explain about the Serengeti Ecosystem? The Serengeti ecosystem, one of the most stunning biological communities in the world, was devastated by the introduction of rinderpest f

Define the herbals, Q. Define the Herbals? During the Middle Ages, foll...

Q. Define the Herbals? During the Middle Ages, following the decline of the Greek and Roman civilisations, little significant botanical progress was made. The early herbals (i.

Determine the interactions among the splicing machinery, Which of the follo...

Which of the following mediates the interactions among the splicing machinery and the mRNA transcript? A. Alpha helical structures within the RNA binding domain of the splicing

Zoology assignment, topics for zoology assignment for plus one

topics for zoology assignment for plus one

What is nucleotides, What is Nucleotides? Nucleotides are the basic b...

What is Nucleotides? Nucleotides are the basic building blocks of nucleic acids. Each nucleotide is composed of a nitrogen base, a 5-carbon sugar called a pentose, and an ass

Compute the amount of nacl need, A saline drip is to be prepared for a lab ...

A saline drip is to be prepared for a lab experiment that is looking at hydration in lab rats. Calculate the amount of NaCl need to make 4 liters of a 0.9% solution.

Define about the yeast - saccharomyces, Define about the Yeast - Saccharomy...

Define about the Yeast - Saccharomyces? Classification Kingdom - Mycetae Division - Amastigomycota Class - Ascomycetes Order - Endomycetales Family - Saccharomyc

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd