Category Archives: Biological Sciences

Polytrichum Life Cycle (Sexual Reproduction) and Structure

There are 92 known species of Genus Polytrichum.

Polytrichum Habitat:

This genus is abundant at damp places. Most of species exist in tropical areas of world and in cool temperate zone.

Structural Features:

Polytrichum can be distinguish into false stem and leaves. True stem and leaves are not present in it like other bryophytes.

Stem:

Stem of Polytrichum is of two type, an aerial stem and underground stem called rhizome. Rhizome is without any leaves and is underground. However it bears root like structures called rhizoids. Rhizoids are involve in absorption of water and nutrients for plant. Erect aerial portion of stem bears leaves.

polytrichum leaf
Polytrichum Leaf

Leaves:

Leaves of Polytrichum has no complicated structure. Upper surface of leaves contain lamellae which increase the surface area of leaf for light capturing. These are structures for photosynthesis. Structure of leaf is shown in figure.

Polytrichum Life Cycle:

Male and female plants of Polytrichum are separate in most of species.

Male gametophyte (n) contain antheridia. Antheridia are produced at the tip of leafy branch called antheridiophore. A cluster of Antheridia is produced at the tip of branch, this cluster looks like flower. Antheridia are intermingle with hair like structures called paraphyses. These paraphyses are somewhat involve in protection of Antheridia. By mitosis inside antheridia, antherozoids (sperms) are produced. Antherozoids contain flagella for movement. After release from antheridia, antherozoids move in water drop towards archegonia.

life cycle of polytrichum
Polytrichum Life Cycle

Female gametophyte (n) produce archegonia at the tip of branch called archegoniophore. Arhegonia has two portions i.e. neck and ventre. Neck contain neck canal cells and beneath these cells ventre canal cells are present. By the bursting of these cells, the passage to ventre become open, and material from these cells also attract antherozoids to archegonia. Egg is produced in ventre portion of archegonia by mitosis.

Fertilization:

Antherozoids travels through water and enter into archegonia, where they fertilize the egg. Fertilized egg (Zygote) then develop into embryo. This is the beginning of diploid generation the sporophyte.

Sporophyte of Polytrichum:

Sporophyte is dependent on gametophyte. It develop from embryo within archegonia. It contains three portions foot, seta and capsule. Foot for attachment to gametophyte and absorption of food. Seta is there to support the capsule. Capsule is the structure where spores are produce. Capsule of Polytrichum has very complex structure.

In the center of capsule there is columella running through out the length. Outer to the columella inner air space is present, this space contain inner trebeculae cells. Outer to this is spore sac, bounded by inner and outer walls. Spore sac is surrounded by outer air space, which also contain trebeculae. This whole arrangement is covered with capsule wall which has two cells thickness. Capsule is covered by calyptra, which is a portion of gametophyte.

Sporophyte produce spores inside spore sac. Spores are produced by meiosis and are haploid. After release from capsule spores germinate at suitable place and develop protonema. A bud is developed on protonema, which give rise to gametophyte. Spores are of two types male and female. So these develop two types of gametophytes male and female accordingly.

There are two generations in life cycle of Polytrichum gametophyte (n) and Sporophyte (2n) which alternate with each other.

Polytrichum Capsule
Polytrichum Capsule

Anthoceros Life Cycle, Sexual and Asexual Reproduction and Structure

Anthoceros belongs to;

Division: Bryophyta
Class: Anthocerotopsida
Order: Antherocerotales
Family: Atherocerotaceae

This genus contains about 200 species, which are distributed all over the world, especially abundant in moist areas of tropical and temperate regions of earth.

Anthoceros Structural Features:

External Structure (Morphology):

Like other bryophytes the dominant generation of Anthoceros is gametophyte. Gametophyte of Anthoceros is dark green in color and has grassy look. It has prostrate stem. This stem shows dichotomous branching. Margins of these branches have lobes. Surface of gametophyte may be hairy, spiny or have ridges. From the ventral side of gametophyte of Anthoceros, rhizoid emerges, which anchor this plant in soil and absorb nutrients for thallus (gametophyte).

Internal Structure (Anatomy):

There is no much differentiation of tissues in gametophyte of Anthoceros. Whole thallus is formed of parenchymatous cells. The dorsal side is lined with upper epidermis and ventral side is lined with lower epidermis. The cells just below upper epidermis contain single lens shaped chloroplast, while deeply situated cells contain 2-4 chloroplasts. Lower surface of gametophyte has cavities which contain Nostoc species, these bacteria fix nitrogen.

Anthoceros Life Cycle (Reproduction)

Anthoceros reproduce by sexual as well as by asexual methods.

Asexual Reproduction (Vegetative Reproduction):

  • Death of older parts of thallus away from the apex of branches cause the separation of branches, each branch is capable of producing new plant.
  • Under unfavorable conditions, the margins of branches of gametophyte become swallow due to storage of food. Unfavorable conditions cause the death of branches but swollen portion survives and restart its growth during favorable conditions and produce new plant.
  • In some species of Anthoceros, during summer the whole plant die, except for apices. These apices produce new plants when summer passed away.
  • Some species of Anthoceros also produce gammae on short stalks on dorsal side of gametophyte. These gammae after getting separated from thallus, produce new plant.

Sexual Reproduction (Life Cycle):

Most species of Anthoceros produce male and female sex organs on same plant. So Anthoceros is homothallic plant. Male sex organs are antheridia and female sex organs are archegonia. Antheridia are developed first on thallu, this condition is called protandrous.Antheridia develop on dorsal side of gametophyte. Special chambers called antheridial chambers are produced on the surface of gametophyte. In each antheridial chambers single or up to 20 antheridia may develop. Each antheridium contains a stalk and ovoid body. Whole antheridium is covered by jacket cells. Inside antheridia, anthorozoids develop by mitosis.Archegonia are embedded in tissue of gametophyte. It does not contain any jacket cells around it, however its upper surface is covered by cover cells. Archegonium contain a swollen portion called ventre and long portion called neck. Neck contains neck canal cells, and ventre contain ventre canal cells and an egg.

Fertilization:

Antherozoids are attracted towards the archegonia chemotactically. The chemical for this movement oozes out by the bursting of neck and ventre canals cells. Antherozoids move into the archegonia and fertilize the egg. Resulting in the formation of zygote. Zygote changes into embryo.Sporophyte:Embryo develops into sporophyte. Sporophyte is diploid generation in life cycle of Anthoceros. Sporophyte of Anthoceros differs from other bryophytes in respect to its semi-dependence on gametophyte. It has chlorophyll in its epidermis to carry out photosynthesis.

Sporophyte of Anthoceros
Sporophyte of Anthoceros

Epidermis also contains stomata for exchange of gases. This feature makes it able to become independent from gametophyte in later stages of its growth. Sporophyte of Anthoceros does not contain well developed seta. The developed structures are foot and long capsule (sporogonium) with calyptra. Capsule contain columella in center and sides of columella has spores. Outer to this spore containing region is well developed and thick wall of capsule which carry out photosynthetic activity. The junction of capsule of and foot has meristematic tissue. This tissue adds new cells throughout the life of sporophyte. This feature resemble the sporophyte of flowering plants, in having the indeterminate growth due to presence of meristem.Spores inside the spore chamber are produced by meiosis. These haploid spores are dispersed after release from sporogonium. On falling at suitable place, spores germinate and produce new thallus.

Anthoceros Life Cycle
Anthoceros Life Cycle

Honeybee Sting Treatment For Diseases

Honeybee sting treatment has been used in curing few diseases. The beneficial effects of honey are well known. But there will be very few people, who know about the usefulness of honeybee sting treatment. Health experts have use honeybee sting for treatment of Arthritis and fibromyalgia, and many other diseases. People around the world, grow up honeybees, and patients are stung by honeybee.

A woman from Los Angeles, says that she was patient of joint pain, and she was stung by 80 honeybees in a day. She feels relaxation in pain now.

A research on mice showed that honeybees sting lessened down the bone diseases.

How To Charge Phone By Plant New Technology

Charge phone by plant, it is not dream now. Science has progressed to such extent to produce a device which can charge phone by plant in a pot.

Chilli: Engineers have created a device which has the ability to take energy form plants and convert this into electricity. The amount of electricity produced by this small device is enough to charge a phone by plant. This device is result of 6 years of efforts by three young scientists.

Device is named as E-Kaia. Such devices has also been created in past. But those were not so much powerful. As those can oly take energy from plant in a large area. But this E-Kaia named device is amazing in this aspect that, E-Kaia only need a single plant in pot to get enough energy to charge phone by plant.

This is rectangle shape device, when it comes in contact with part of plant, it start extracting energy from it. The value of this energy or suitable you can say the amount of electricity it extract is almost 600 mA. This is most important thing, as this amount of electricity can charge a phone within one and half hours almost. Ordinary charges also take same time to charge a phone.

Engineers of this device has also said that, E-Kaia is only a start. There are many chances for its improvement. In future, such devices will be able to extract energy from large plants and will provide energy to large electrical devices.

However at present. It is a blessing for those areas where electricity is a problem. Now is time to charge Phone by plant.

Red Shifted Chlorophyll Facts

Red Shifted Chlorophyll:

Chlorophylls are molecules which absorb light during photosynthesis. We are familiar with four different types of chlorophylls molecules, termed as Chlorophyll a, Chlorophyll b, Chlorophyll c, and Chlorophyll d. All these pigments can be found within light harvesting complex of photosystem. For a long time Chl a pigment has been demonstrated as main pigment which carry out the energy transduction in the photosynthates. But after that it was determined that Chl d can also serve the same role in oxygenic photosynthesis. This assumption was based on discovery that Acaryochloris marina a cyanobacteria has 99% chlorophyll d of total pigment in its photosystem.

In the study carry out by Chen et al., (2010) a new chlorophyll pigment has been demonstrated, which is named as Chl f. In this study a sample from the Hamelin pool was cultured under the light near infrared. The extract of chlorophylls, from stromatolites of Shark Bay which is locality in Western Australia, was obtained by the methane. This extract was analyzed by HPLC, the results shows a large amount of Chl a and bacteriochlorophyll a, traces of Chl d and a new pigment Chl f.

The study on optimum absorption, shows that this Chl f molecule absorb maximum wavelength of 706 nm. This shows a red shift in absorption spectrum compared to other molecules of chlorophyll. A change in absorption spectrum was also noted in blue region of light. This shift in blue absorption shows that maximum absorption is at 407 nm. Further analysis shows that Chl f is synthesized in filamentous cyanobateria. This discovery about synthesis is based on 16S ribosomal RNA sequencing of purest culture which contain only Chla and Chl f.

Molecular formula of Chl f assigned is C55H70O6N4Mg by mass spectral analysis. Formyle group was indentified by NMR spectroscopy of Chl f. Structure of other chlorophyll molecules shows that Chl d has fomyle group at carbon number 3 and methyl group at C-2, Chl a has CH3 at C-2, and Chl b has methyl group at C-2 and formyle group at C-7. But newly discovered Chl f molecule has formyle group at C-2 position. This structural change in Chl f compared to other molecules of Chlorophylls, enable it to absorb a light of different wavelength.

λmax(red region) = 706nm and λmax (blue region) = 406nm

 Reference:

Chen, M., M. Schliep, R. D. Willow, Z. Cai, B. A. Neilan and H. Scheer. (2010). A red shifted chlorophyll. Science. 329: 1318-1319.

Cardoon Cynara Cardunculus Facts and Medical Uses

The purple flower(Cardoon Cynara cardunculus) in above figure is looking very beautiful. But this plant is not known for its beauty it is an important plant with respect to medicinal and food uses.

Scientific Name: Cynara cardunculus

Common Names: Cardoon and in Urdu it is known as oont katara.

Uses: Food, Medicine (specially liver medicines), also grown as ornamental plant, due to its beautiful flower.

Origin: Western, however this was domesticated very early, so there is no surety about its origin.

Edible Parts: Flowers Bud of Cardoon (Cynara cardunculus) can cooked, Young Leaves, stem and even roots can be use as food.

Cardoon Cynara Cardunculus Medical Uses:

Cardoon Cynara cardunculus has gain a lot of importance during last few years, due to discovery of cynarin compound. That’s why the leaves Cardoon can be use as to improve the liver and stimulate the digestive tract. Gall Bladder diseases are treated with Cardoon leaves. That’s why Cardoon can be use to cure Jaundice, Hepatitis and in early stages of diabetes.