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How stigma helps in the wind pollination?
Depending on the type of pollinators, the pollen grains may be sticky or light. Exine present on the pollen grains as the outermost covering layer is contributed by the tapetum cells. Reaching on the stigma after pollination, the stigmatic cells interact with the material of exine to determine the compatibility of the pollen to allow its germination for fertilization.
Is there pollen grain inside the pollen cell?
A single pollen grain contains the generative material that forms the male gametes. It also contains the material that will form the pollen tube when the pollen lands on the pistil. These are covered by a thin layer called the intine or endospore as well as a thick protective wall called the exine or exospore.
What is the Outer layer of grain?
The outer covering of the grain is called Husk. :) - HAO -
The continuous part of the plasma membrane is the?
The continuous part of the plasma membrane is the outer layer.
What is the vascular layer of the eyeball that is continuous with the iris?
uveitis
What are exine seeds?
In botany 'exine' is the outer coat, or the outer layer, of the wall of a pollen grain. It is composed of a durable organic polymer
What is sporoderm?
Sporoderm is the outermost protective wall around the pollen grain or microspore. It is made up of many layers. The two main layers are Exine and Intine. Exine is outer while Intine is inner layer of sporoderm.
How stigma helps in the wind pollination?
Depending on the type of pollinators, the pollen grains may be sticky or light. Exine present on the pollen grains as the outermost covering layer is contributed by the tapetum cells. Reaching on the stigma after pollination, the stigmatic cells interact with the material of exine to determine the compatibility of the pollen to allow its germination for fertilization.
Is there pollen grain inside the pollen cell?
A single pollen grain contains the generative material that forms the male gametes. It also contains the material that will form the pollen tube when the pollen lands on the pistil. These are covered by a thin layer called the intine or endospore as well as a thick protective wall called the exine or exospore.
What is the pollen case?
What is usually meant by pollen case is the outer protective coat of the pollen grain. It is a highly modified cell wall, with two layers. The interior layer is largely pectocellulose (a combination of pectin and cellulose) with a bit of callose, and the exterior is made of sporopollenin. Sporopollenin is so tough that its exact chemical structure has not been figured out. Atop the sporopollenin layer is a deposit of sticky goo made of pollenkitt and/or tryphine.
What is the Outer layer of grain?
The outer covering of the grain is called Husk. :) - HAO -
The continuous part of the plasma membrane is the?
The continuous part of the plasma membrane is the outer layer.
Is it true that the earths surface is covered by a continuous layer of soild rock?
s it true that the earths surface is covered by a continuous layer of solid rock?
What is the vascular layer of the eyeball that is continuous with the iris?
uveitis
The tunica interna is continuous with this layer of the heart?
Endocardium
The internal layer of the tissue in the heart is the epicardium?
Epicardium is the outer layer of heart tissue. When considered as part of the pericardium, it is the inner layer, continuous with the serial layer.
What is significance of evolution shown by he flagellated Cycas sperm?
Cycads and other gymnosperms do not have true flowers and their seeds are borne naked. All species of cycads are dioecious. The male reproductive structure, androstrobilus, consists of microsporophylls. Each microsporophyll produces a large quantity of pollen grains on its dorsal surface. The pollen is dispersed by wind or by insects to the gynostrobilus, the female reproductive structure. When a pollen grain lands on the gynostrobilus, it germinates and grows a pollen tube that extends to deep within the multicellular, female haploid gametophyte. Then a sperm cell of the pollen grain swims through the pollen tube using its whip-like tail, or flagella, and fertilizes the egg to form a zygote. The zygote eventually develops into an embryo, and then a seed. Cycad seeds are rich in starch and have a pigmented, fleshy outer layer known as the sarcotesta. The seeds are often dispersed by birds or mammals, which eat them for the nutritious sarcotesta, and later defecate the still-viable seed.
