This document discusses the classification and economic importance of bryophytes. It classifies bryophytes into three classes: Hepaticopsida (liverworts), Anthocerotopsida (hornworts), and Bryopsida (mosses). It describes key characteristics of each class. Bryophytes have economic importance as they help prevent soil erosion, aid in soil formation, can retain large amounts of water, and peat made from sphagnum is used as fuel and manure. Bryophytes also serve as a food source for animals in some areas and some species have medicinal uses or are used as indicator plants.
The plant body in algae is always a thallus. It is not differentiated in root, stem and leaves. Algae range in size from minute unicellular plants (less than 1 µ in diameter in some planktons) to very large highly differentiated multicellular forms e.g., some sea-weeds.
Their forms may be colonial (loose or integrated by inter-connections of protoplasmic strands), filamentous (branched or un-branched), septate (branched or un-branched), non-septate or branched, multinucleate siphonaceous tube where the nuclear divisions occur without usual septa formation.
The plant body in algae is always a thallus. It is not differentiated in root, stem and leaves. Algae range in size from minute unicellular plants (less than 1 µ in diameter in some planktons) to very large highly differentiated multicellular forms e.g., some sea-weeds.
Their forms may be colonial (loose or integrated by inter-connections of protoplasmic strands), filamentous (branched or un-branched), septate (branched or un-branched), non-septate or branched, multinucleate siphonaceous tube where the nuclear divisions occur without usual septa formation.
This ppt has been made by Xanthophyceae also known as yellow green algae. It occupies second position in algae classification by F.E Fritsch. It is classified into four orders. It contain xanthophyll in large amount that gives it yellow colour, hence it is commonly know as yellow green algae.
This ppt has been made by Xanthophyceae also known as yellow green algae. It occupies second position in algae classification by F.E Fritsch. It is classified into four orders. It contain xanthophyll in large amount that gives it yellow colour, hence it is commonly know as yellow green algae.
Bryology - Masters First semester revision text.pdfAleenaRose4
A reference text for Bryology - 1. General characters and systems of classifications of Bryophytes
2. General account of the anatomy, reproduction, life history and phylogeny of Sphaerocarpales, Marchantiales,
Jungermanniales, Calobryales, Anthocerotales, Sphagnales, Andreales, Funariales and Polytrichales
3. Origin and evolution of Bryophytes- gametophytic and sporophytic.
4. A general account of fossil Bryophytes and their affinities.
5. Economic importance of Bryophytes.
Ascent of sap- Transpiration pull theory, Transpiration-Types of transpiration, mechanism of transpiration-Starch sugar interconversion theory and Potassium pump theory
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Unveiling the Energy Potential of Marshmallow Deposits.pdf
6. Classification and economic importance of bryophytes
1. Classification and economic importance of
Bryophytes
Dhole N. A.
Department of Botany,
Digambarrao Bindu ACS College, Bhokar
2. Classification of bryophytes:
According to the latest recommendations of ICBN (International Code of
Botanical Nomenclature), bryophytes have been divided into three
classes.
1. Hepaticopsida (Liverworts)
2. Anthocertopsida (Hornworts)
3. Bryopsida (Mosses)
3. Class 1. Hepaticopsida:
1. Gametophytic plant body is either thalloid or foliose. If foliose, the
lateral appendages (leaves) are without mid-rib. Always dorsiventral.
2. Rhizoids without septa.
3. Each cell in the thallus contains many chloroplasts; the chloroplasts
are without pyrenoi.
4. Sex organs are embedded in the dorsal surface.
5. Sporophyte may be simple (e.g., Riccia) having only a capsule, or
differentiated into root, seta and capsule (e.g., Marchantia, Pallia and
Porella etc.)
6. Capsule lacks columella.
4. 7. It has 4 orders:
(i) Calobryales
(ii) Jungermanniales
(iii) Spherocarpales
(iv) Marchantiales.
5. Class 2. Anthocerotopsida:
1. Gametophytic plant body is simple, thalloid; thallus dorsiventra
without air cambers, shows no internal differentiation of tissues.
2. Scales are absent in the thallus.
3. Each cell of the thallus possesses a single large chloroplast with a
pyrenoid.
4. Sporophyte is cylindrical only partly dependent upon gametophyte
for its nourishment. It is differentiated into bulbous foot and cylindrical
capsule. Seta is meristematic.
5. Endothecium forms the sterile central column (i.e., columella) in the
capsule (i.e. columella is present).
6. It has only one order-Anthocerotales.
6. Class 3. Bryopsida:
1. Gametophyte is differentiated into prostrate protonema and an erect
gametophores
2. Gametophore is foliose, differentiated into an axis (=stem) and
lateral appendages like leaves but without midrib.
3. Rhizoids multi-cellular with oblique septa.
4. Elaters are absent in the capsule of sporangium.
5. The sex organs are produced in separate branches immersed in a
group of leaves.
7. 6. It has only three orders:
(i) Bryales,
(ii) Andriales and
(iii) Sphagnales.
8. Economic importance of Bryophytes:
1. Protection from soil erosion:
Bryophytes, especially mosses, form dense mats over the soil and prevent soil
erosion by running water.
2. Soil formation:
Mosses are an important link in plant succession on rocky areas. They take
part in binding soil in rock crevices formed by lichens. Growth of Sphagnum
ultimately fills ponds and lakes with soil.
3. Water retention:
Sphagnum can retain 18-26 times more water than its weight. Hence, used by
gardeners to protect desiccation of the seedling during transportation and
used as nursery beds.
4. Peat:
It is a dark spongy fossilized matter of Sphagnum. Peat is dried and cut as
cakes for use as fuel. Peat used as good manure. It overcomes soil alkalinity
and increases its water retention as well as aeration. On distillation and
fermentation yield many chemicals.
9. 5. As food:
Mosses are good source of animal food in rocky and snow-clad areas.
6. Medicinal uses:
Decoction of Polytrichum commune is used to remove kidney and gall bladder
stones. Decoction prepared by boiling Sphagnum in water for treatment of eye
diseases. Marchantia polymorpha has been used to cure pulmonary tuberculosis.
7. Other uses:
Bryophytes arc used as packing material for fragile goods, glass wares etc. Some
bryophytes act as indicator plants. For example, Tortell tortusa grow well on soil
rich in lime.
