The sculpturing of the pollen grain is the ornamentation of the exine surface which can be psilate, foveolate, areolate (frustillate), gemmate, clavate, verrucate, baculate, echinate, rugulate, striate or reticulate.

What is tectum in pollen grain?

Tectum is a term used to describe a structure resembling a roof. Tectum is also used to refer to the roof-like protrusions on the outer surface of a pollen or a spore. When a pollen grain has tecta on its outermost layer, it is described as tectate. When there are no tecta, the pollen is described as intectate.

What is Tectate exine?

Exine: Tectate. Perforate. Surface having small holes or depressions less. than 1μm in diameter.

What are the different types of pollen grains?

On the basis of aperture types pollen grains of most families are grouped under three distinct types, namely colporate, colpate and porate. On the other hand, pollen grains of some families e.g. Cyperaceae, Juncaceae, Potamogetonaceae and Ruppiaceae are inaperturate.

What is Sexine and Nexine?

In angiosperms, the pollen exine is divided into sexine and nexine. The non-sculptured nexine is distinguished as a distinct layer between the sculptured sexine and an inner intine, which appears to be strongly conserved in seed plants13,14,15.

What is the ploidy of Microspores?

haploid
MMC may be a diploid cell that undergoes meiosis to make four haploid microspores which are arranged during a tetrad. This process is understood as microsporogenesis. Each of those four microspores are found to be developed into a pollen grain. This tells us that the ploidy of microspore tetrad cells is haploid.

What does the word tectum mean?

Definition of tectum : a bodily structure resembling or serving as a roof especially : the dorsal part of the midbrain. Other Words from tectum Example Sentences Learn More About tectum.

Is sperm a pollen?

Pollen is technically a male gametophyte, meaning an organism that makes “gametes”, which in this case is sperm. In its simplest form, pollen has three cells: one vegetative cell enclosing two sperm cells. So we’re all covered in plant sperm.

What is the function of exine of pollen?

In addition to the purely mechanical function of the exine in protecting the reproductive cells from environmental injury, exine sculpturing plays an important role in attachment to insect pollinators and adhesion to the stigmatic surfaces; while wind pollinated species including many grasses and tree species often …

Where is exine located?

5 Exine Architecture Exine is commonly divided into the outer sculptured sexine and the sim- pler inner nexine, located just above the intine (Figure 2a,d).

What are pollen grains 7?

POLLEN GRAINS:- the granular microspores that occur in pollen and give rise to the male gametophyte of a seed plant.

Which layer of pollen wall is divided into two layers namely Sexine and Nexine?