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

Survival of the saddleback, The North Island saddleback or tieke, Philestur...

The North Island saddleback or tieke, Philesturnus rufusater, is an endemic New Zealand bird. Saddlebacks inhabit the middle or lower layers of the forest, and eat small invertebra

Heat exchangers, Normal 0 false false false EN-IN X-N...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Explain about the proteins, Explain about the Proteins? Proteins, as yo...

Explain about the Proteins? Proteins, as you may already know, are made up of carbon, hydrogen, nitrogen, oxygen and usually sulphur. Proteins are built up of a large number of

Explain thermal decomposition heating of food, Explain Thermal Decompositio...

Explain Thermal Decomposition Heating of food Thermal Decomposition Heating of food produces various chemical changes, some of which can be important to flavour, appearance, nu

Define heart rate (hr) method - aerobic capacity, Define Heart Rate (HR) M...

Define Heart Rate (HR) Method -  aerobic capacity? An alternative method for determining aerobic capacity involves the measurement of heart rate. Heart rate is linearly associa

Define the dietary management for underweight, Define the Dietary Managemen...

Define the Dietary Management for Underweight? We just read about the etiological factors that may lead to undernutritioin and weight loss. Whatever may be the cause, all under

Define measuring direct aerobic fitness, Define Measuring Direct Aerobic Fi...

Define Measuring Direct Aerobic Fitness (VO 2 max) For direct measurement of VO, max, the subject is asked to perform exercise for 12 to 15 minutes. A stationary bicycle or a

Oxaloacetate to malate, Oxaloacetate to Malate Oxaloacetate to Malate:...

Oxaloacetate to Malate Oxaloacetate to Malate: Oxaloacetate cannot  permeate mitochondria 1 membrane well and it must be transported across the membrane in the form of malate

Illustrate the metabolism of cornea, Illustrate the metabolism of cornea? ...

Illustrate the metabolism of cornea? Metabolism of Cornea: The corneal epithelium plays several roles in the process of image formation. Its apical cell border interacts

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