Wet stigma - category of stigma, Biology

Assignment Help:

Wet Stigma - Category of Stigma

Petunia shows several randomly distributed 2-celled papillae on its surface. In a developing stigma, the epidermis is covered by a continuous, thin cuticle and the subepidermal cells are densely cytoplasmic, without any intercellular spaces. In a mature stigma, the cells of the subepidermal zone elongate to form a secretory zone with large schizogenous cavities filled with a lipoidal secretion. The secretory zone is delimited from the basal part of the stigma by a storage zone.

The cells of the stigma contain numerous amyloplasts and a large amount of lipid globules which gradually coalesce and migrate to the peripheral part of the cytoplasm and eventually out of the cell. The lipoidal exudate accumulates between the cell wall and the cuticle. In the secretory zone the exudate fills the large intercellular, schizogenous cavities. At the time of anthesis, the epidermis becomes disorganized, the cuticle is discarded in the form of flakes and the accumulated exudate spreads over the entire surface of stigma. A very thin layer of water is also trapped.


Related Discussions:- Wet stigma - category of stigma

Virus, assignment order

assignment order

Rheumatic heart disease, Rheumatic heart disease was the predisposing cardi...

Rheumatic heart disease was the predisposing cardiac lesion for IE in 20 to 25 per cent. In patients with rheumatic heart disease, endocarditis occurs most frequently on the mitral

Sea, sea divisions

sea divisions

Determine the functional brain activity, Determine the functional brain act...

Determine the functional brain activity PET is powerful means of assessing functional brain activity, although it does not directly measures neuronal events. Rather it indicate

Nervous system - spinal cord, SPINAL CORD (MYELON) It is part of CNS. 4...

SPINAL CORD (MYELON) It is part of CNS. 45 cm long (in woman 43 cm) & weight 35 gms. Origi n from lower part of medulla oblongeta. Shape - Long cylindrical,

Spreading mechanisms of the disease, Talk about briefly three  of the commo...

Talk about briefly three  of the common enteric diseases caused by inadequate clean water supply and insufficient sanitation facilities. Your talk should contain the source and spr

Breeding of crops with high levels of minerals is called, Breeding of crops...

Breeding of crops with high levels of minerals, vitamins and proteins is called: 1. Somatic hybridisation 2. Biofortification 3. Biomagnification 4. Micropropagation

What is the mechanism described by darwin, What is the mechanism described ...

What is the mechanism described by Darwin that eliminates species less adapted to environmental conditions? The mentioned mechanism is the natural selection.

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