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Everyday connection

Incompatibility genes in flowers

In recent decades, incompatibility genes—which prevent pollen from germinating or growing into the stigma of a flower—have been discovered in many angiosperm species. If plants do not have compatible genes, the pollen tube stops growing. Self-incompatibility is controlled by the S (sterility) locus. Pollen tubes have to grow through the tissue of the stigma and style before they can enter the ovule. The carpel is selective in the type of pollen it allows to grow inside. The interaction is primarily between the pollen and the stigma epidermal cells. In some plants, like cabbage, the pollen is rejected at the surface of the stigma, and the unwanted pollen does not germinate. In other plants, pollen tube germination is arrested after growing one-third the length of the style, leading to pollen tube death. Pollen tube death is due either to apoptosis (programmed cell death) or to degradation of pollen tube RNA. The degradation results from the activity of a ribonuclease encoded by the S locus. The ribonuclease is secreted from the cells of the style in the extracellular matrix, which lies alongside the growing pollen tube.

In summary, self-incompatibility is a mechanism that prevents self-fertilization in many flowering plant species. The working of this self-incompatibility mechanism has important consequences for plant breeders because it inhibits the production of inbred and hybrid plants.

Pollination by insects

Bees are perhaps the most important pollinator of many garden plants and most commercial fruit trees ( [link] ). The most common species of bees are bumblebees and honeybees. Since bees cannot see the color red, bee-pollinated flowers usually have shades of blue, yellow, or other colors. Bees collect energy-rich pollen or nectar for their survival and energy needs. They visit flowers that are open during the day, are brightly colored, have a strong aroma or scent, and have a tubular shape, typically with the presence of a nectar guide. A nectar guide    includes regions on the flower petals that are visible only to bees, and not to humans; it helps to guide bees to the center of the flower, thus making the pollination process more efficient. The pollen sticks to the bees’ fuzzy hair, and when the bee visits another flower, some of the pollen is transferred to the second flower. Recently, there have been many reports about the declining population of honeybees. Many flowers will remain unpollinated and not bear seed if honeybees disappear. The impact on commercial fruit growers could be devastating.

 Photo depicts a bee covered in dusty yellow pollen.
Insects, such as bees, are important agents of pollination. (credit: modification of work by Jon Sullivan)

Many flies are attracted to flowers that have a decaying smell or an odor of rotting flesh. These flowers, which produce nectar, usually have dull colors, such as brown or purple. They are found on the corpse flower or voodoo lily ( Amorphophallus ), dragon arum ( Dracunculus ), and carrion flower ( Stapleia , Rafflesia ). The nectar provides energy, whereas the pollen provides protein. Wasps are also important insect pollinators, and pollinate many species of figs.

Questions & Answers

The different between animal cells and plant cells
Bridget Reply
plant cells have a cell wall and chloroplast but animal cells don't. vacuoles of plant cells are much larger than that of an animal cell.
Yazi
explain pyramids of numbers
Saanui Reply
a structure of the nerve cell
Ntale Reply
how many types of viruses do we have
amofa Reply
12
angelina
we Ave 21 families rna and dna viruses
Opeyemi
14 virus
Peter
what is the difference between gems and virus?🙄
Peter
What is nucleoprotein particles
Zanga Reply
nucleoprotein particles could be , tiny micro organizims regenerated and conducted matter.? 'is the least scary idea.'
Heidi
state the factors that determine energy requirements in human body?
Samson Reply
Name and explain 2 nutrients that do not require digestion before they are absorbed
Samson
Name and explain 2 nutrients that do not require digestion before they are absorbed
Samson
Name and explain 2 nutrients that do not require digestion before they are absorbed
Samson
Name and explain 2 nutrients that do not require digestion before they are absorbed
Samson
Name and explain 2 nutrients that do not require digestion before they are absorbed
Samson
Name and explain 2 nutrients that do not require digestion before they are absorbed
Samson
Name and explain 2 nutrients that do not require digestion before they are absorbed
Samson
water : it's a nutrient which helps in d proper digestion of nutrients, it doesn't require digestion because it's not affected by any factor in d mouth, and digestion start from the buccal cavity.
aweda
What are the relationship between Biology and Agriculture
Chisco Reply
what are the relationship between biology and chemistry
Abel
Hooliganism the study of living things(plants and animals) and chemistry focuses on chemical composition of matter.😊
Ronke
biology is the study of all life whereas agriculture is the science of cultivating the land including harvesting of crops, rearing and management of animals and tillage
angelina
biology is the study of life
Elizabeth
biology is the study of livingthing and non livingthing
Fahamia
boilogy is the study of life whilst agriculture is the study of crops etc...
Amoah
which cell organelle is found in abundance in skeletal tissue
Samson Reply
What are the functions of the cell membrane?
Samson Reply
Detects self cells and foreign cells during invasion by pathogens in the cell Protects the cell content Makes the cell very flexible in its function To regulate the entry n exit of substances in and out of the cell(selective permeability)
Agyei
controls the movement of substance in and out of the cell
Queen
cell membrane control movement in the cell
Amoah
what is the four chambers of the human heart and their functions.
Ismile Reply
right and left auricles right and left ventricles
Faith
In which group of the periodic table is beryllium?
Stuart Reply
2
Agyei
are we dealing with biology or chemistry
Samuel
We are dealing with biology
Godfred
what are the terminology in genetic
Odinaka Reply
I want to know if the following stated is be 1.increase, 2. decrease, 3. steady. 1. blood pressure 2. Blood volume 3. ECF volume 4. ICF volume 5. HCT volume 6. Blood protein concentration 7. ECF protein concentration 8. ICF protein concentration 9. Oxygen supply to the brain cells
Rinda Reply
increase
Favour
What are the types of cells?
Akuoch-magol
the two main type of cells are prokaryotic cell and eukaryotic cell but there are also other cells in the human body such as:the nerve cell,skin cell ,blood cell,bone cell etc
angelina
eukaryote cell prokaryotic cell erkayortic cell
Elizabeth
what is the word phylogeny means?
Bae Reply
what is the word biology means?
bio-study logos(logy)- life so biology means the study of life
okonkwo
Please what's the meaning of deductive reasoning
Godfred
the evolutionary history of a kind of organisms
Elizabeth
The best way to understand cell structure is?
katrina Reply
What is the term binomial nomenclature
katrina
What is the term binomial nomenclature
katrina
Is the double name of loving things
Collins
is the double naming of living organisms
Akuoch-magol
what is the function of a nucleus
Japheth Reply

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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