Pollen stigma interaction - stigma, Biology

Assignment Help:

Pollen Stigma Interaction - Stigma

The Stigma After landing on the stigma pollen grain germinates, and produces a pollen tube that carries the male gametes. The stigma has been classified into two principal types depending on the presence or absence of stigmatic exudate at the time of pollination:

  1. The wet stigma is covered by a sticky secretion, e.g., Aegle marmelos and Petunia hybrida, and
  2. The dry stigma lacks any secretion, e.g., cotton.

EM observations indicate that the exudate is secreted by the ER and it is extruded by exocytosis. The diagrammatic representation of the mechanism involved is shown in Figure. In some plants such as Lilium, the stigma is non-secretory. The exudate which is present on stigma is, in fact, secreted by the stigmatic papillae and those present in the stylar canal emanate from the style.


Related Discussions:- Pollen stigma interaction - stigma

Parts of a seed , Parts of a Seed Seed is attached to the fruit by a ...

Parts of a Seed Seed is attached to the fruit by a stalk, the funiculus (funicle). The prolongation of the funiculus running along the seed and terminating at the chalaza is

Theory of epigenesis - pre-mendelian theory, Theor y of Epigenesis (i)...

Theor y of Epigenesis (i)          It was proposed by C.F. Wolff & supported by Von Baer. (ii)         Wolff proposed that germ cells contain definite but undifferentiated

Energy, Energy Contrary  to matter.  Energy neither occupies space, nor...

Energy Contrary  to matter.  Energy neither occupies space, nor possesses mass. Hence it is defined, not on   physical ,but on operational or functional basis as the force whic

Dna and rna, why uracil is present in rna and thymine in dna?

why uracil is present in rna and thymine in dna?

What is the absolute pressure at the bottom of the container, A container i...

A container is filled to a depth of 20.0 cm with water. On top of the water floats a 30.0-cm-thick layer of oil with specific gravity 0.700. What is the absolute pressure at the bo

Define the visual accommodation, Q. What is visual accommodation? Visua...

Q. What is visual accommodation? Visual accommodation is the phenomenon of varying the curvature of the crystalline lens to make possible the difference of its refractivity to

Structure of mitochondria, STRUCTURE Mitochondria is a double unit memb...

STRUCTURE Mitochondria is a double unit membranous structure. It consists of outer & inner membranes. Outer membrane is smooth & made up of lipoproteins. It bears m

Sectioned and formed meats, S e c t i o ned and Formed Meats Thes...

S e c t i o ned and Formed Meats These are technically speaking restructured products, since they are partially disassembled and then reassembled to form products resembl

What is nucleus where it is found, What is nucleus where it is found? ...

What is nucleus where it is found? Nucleus :  The nucleus is present only in eukaryotic cells. It is the control center and is generally found in the center of the cell. The

Describe the plasma homocysteine levels, Describe the Plasma Homocysteine l...

Describe the Plasma Homocysteine levels ? Several studies have investigated the contribution of homocysteine to CVD risk both among immigrant Indians and those living in India.

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