Seed viability refers to a seed's ability to germinate and is affected by various conditions. Viability is highest at physiological maturity and then declines over time, with lifespan varying greatly between species. Conditions like cold, dry storage help maximize longevity. Factors like mechanical damage, incomplete pollination, weathering, moisture content, temperature, and fungi can all negatively impact viability during development and storage. Proper drying and storage at low moisture levels and temperatures can extend viability significantly.
Self-incompatibility refers to the inability of a plant with functional pollen to set seeds when self pollinated. It is the failure of pollen from a flower to fertilize the same flower or other flowers of the same plant.
This presentation includes, Single-locus self-incompatibility- {Gametophytic self-incompatibility (GSI) and Sporophytic self-incompatibility (SSI)},2-locus gametophytic self-incompatibility, Heteromorphic self-incompatibility,Cryptic self-incompatibility (CSI) and Late-acting self-incompatibility (LSI).
Self-incompatibility refers to the inability of a plant with functional pollen to set seeds when self pollinated. It is the failure of pollen from a flower to fertilize the same flower or other flowers of the same plant.
This presentation includes, Single-locus self-incompatibility- {Gametophytic self-incompatibility (GSI) and Sporophytic self-incompatibility (SSI)},2-locus gametophytic self-incompatibility, Heteromorphic self-incompatibility,Cryptic self-incompatibility (CSI) and Late-acting self-incompatibility (LSI).
Plant breeding methods of vegetatively propagated crops Roksana Aftab Ruhi
Vegetatively propagated crops are bred by intentionally crossing of closely or distantly related individual to produce new crop varieties or lines with desirable traits. Breeding of vegetative crops have successfully improved quality, yield, tolerance of crops to environmental pressure. Breeding helps in producing crops that are resistant to viruses, fungi and bacteria and helps in longer storage period for the harvested crop.
Plant breeding methods of vegetatively propagated crops Roksana Aftab Ruhi
Vegetatively propagated crops are bred by intentionally crossing of closely or distantly related individual to produce new crop varieties or lines with desirable traits. Breeding of vegetative crops have successfully improved quality, yield, tolerance of crops to environmental pressure. Breeding helps in producing crops that are resistant to viruses, fungi and bacteria and helps in longer storage period for the harvested crop.
Seed is the most important asset in the agriculture. seeds have to be stored for the next season. so it is important to study the seed storage physiology and gnetics
Minimize seed deterioration during it’s storage of orthodox or recalcitrant s...AKHILRDONGA
PG major SEMINAR on minimize seed deterioration during its storage of orthodox or recalcitrant seed ppt file delivered by Pratik Bhankhar (M.Sc. Seed Science and Technology) at C. P. College of Agriculture, S. D. Agricultural University, Sardarkrushinagar.
it contains How to minimize the seed deterioration during its storage.
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.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
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 .
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.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
3. Seed viability is the ability of the embryo to germinate
and is affected by a number of different conditions
(or)
Seed viability is the capability of plant structure (seed,
cuttings etc.) to show living properties like
germination and growth.
( or )
The degree to which the seed is alive (metabolically
active)
4. SEED VIABILITY
Viability is highest at the point of physiological maturity
and then gradually declines
Average life span of a seed is 10 to 15 years.
Some are very short-lived. e.g. willow (< 1 week)
Some are very long-lived. e.g. mimosa 221 years
Conditions are very important for longevity
Cold, dry, anaerobic conditions
These are the conditions which are maintained in seed
banks
8. Mechanical injury to seeds by threshing usually contributes to
immediate reduction in germination capacity and to an accelerated
loss of viability in storage.
Wahlen (1929) found that viability in clover seeds depend upon the
impermeability of the seed coat.
Alison et al (1990) studied poor seed emergence of pea, Vicia faba,
Phaseolus vulgaris, Chick pea, cow pea and long bean and found
associated with genotypes having white or unpigmented seed coat.
Genotypes with pigmented seed coats showed high levels of seed
viability .
9. Incomplete pollination results in a high proportion of
empty seeds.
They look like seeds, but there is no embryo, or one
which is only partly developed.
Most viable seeds are positioned around the outer
perimeter of the head.
As flowers and vegetables are further and further
hybridized to produce color and style which is more and
more remote from the natural parents, the viability of the
"germ" is reduced.
10. Mechanical damage during harvesting can severely
reduce the viability of some seeds, e.g.., certain large
seeded legumes.
Cereals are largely immune from mechanical injury,
presumably because of the protective outer structures,
the palea and lemma.
Small seeds tend to escape injury during harvest, and
seeds that are spherical tend to suffer less damage than
irregular or elongated shaped seeds.
11. Bacteria do not play a significant role in seed deterioration, since it
requires free water to grow.
If conditions were moist enough , this would encourage growth of
fungi which would suppress bacterial growth.
Two types of fungi invade seeds: 1) FIELD FUNGI
2) STORAGE FUNGI
FIELD FUNGI;
These invade seeds during their development on plants in field.
They need a high moisture content for growth.
A period of high rainfall at the time of harvest result in extensive
grain deterioration.
ex: Alternaria, Fusarium and Helminthosporium
12. STORAGE FUNGI:
They infest seeds only under storage conditions.
The major deleterious effects of storage fungi are to
Decrease viability
Cause discoloration
Produce mycotoxins
Cause heat production
13. Different seeds from the same seed pod will have
different degrees of viability in the embryo.
Some will germinate at once, or go into "deep dormancy",
or have insufficient viability to germinate at a later date.
Similarly, different seeds from the same seed pod will
have a "chemical" lock which will not degrade except for
the passage of time.
14. •Environmental variation during seed development
usually had a little effect on the viability of seeds unless
the ripening process is interrupted by premature
harvesting.
•Weathering of mature seeds in the field particularly in
conditions of excess moisture or freezing temperatures,
results in a product with inferior storage potential.
15.
16. The amount of moisture in the seeds is the most important factor
influencing seed viability during storage.
Generally if the seed moisture content increases storage life
decreases.
If seeds are kept at high moisture content the losses could be very
rapid due to mould growth
If they are kept at very low moisture content below 4% may also
damage seeds due to extreme desiccation or cause hard seededness in
some crops.
17. The life of a seed largely revolves around its moisture
content.
It is necessary to dry seeds to safe moisture contents.
The safe moisture content however depends upon
storage length, type of storage structure, kind / variety of
seed type of packing material used.
For cereals in ordinary storage conditions for 12-18
months, seed drying up to 10% moisture content appears
quite satisfactory.
However, for storage in sealed containers, drying upto
5-8 % moisture content depending upon particular kind
may be necessary.
18. Harringtons thumb rule on seed moisture content :
For every one per cent decrease in seed moisture content the life of seed
will be doubled. This is again hold good between 4- 12 °C.
Based on the tolerance and susceptibility of seeds towards moisture loss,
seeds are classified into
Orthodox – the seeds able to tolerate moisture loss and less seed moisture
favors the storage. i.e. decreased moisture increased storage period.
Eg. Rice, sorghum , and most of the cultivated species.
Recalcitrant – just opposite to the orthodox. Seeds not able to tolerate
moisture loss. Required high moisture for viability maintenance.
19. Temperature also plays an important role in life of seed.
Insects and moulds increase as temperature increases.
The higher the moisture content of the seeds the more they are
adversely affected by temperature.
Decreasing temperature and seed moisture is an effective means
of maintaining seed quality in storage.
The thumb rules by Harrington are useful measures for assessing
the effect of moisture and temperature on seed storage.
20. These rules are as follows.
1.For every decrease of 1% seed moisture content the life of the
seed doubles. This rule is applicable between moisture content
of 5-14%.
2. For every decrease of 5°C in storage temperature the life of
the seed doubles. This rules applies between 0°C to 50°C.
3. Good seed storage is achieved when the % of relative
humidity in storage environment and the storage temperature
in degrees Fahrenheit add up to one hundred but the
contribution from temperature should not exceed 50 ° F.
21. ABSORPTION ISOTHERM
Phase 1
Phase2
Phase 3
10 20 30 40 50 60 70 80 90 100
Safe for seed
storage
Not safe for storage
Short term
storage
18
16
14
12
10
8
6
4
2
Relative humidity (%)
Moisturecontent(%)
22. Roberts (1973) developed formulae to describe the
relationship between temperature seed Moisture content
and period of viability.
From these relationships it was possible to construct a
seed viability nomograph.
These nomograph are helpful in predicting the retention
of seed viability indefined storage environment for a
particular period or to determine combinations of
temperature and moisture content which will ensure the
retention of a desired level of seed viability for specific
period.
24. Relative humidity is the amount of H2O present in the
air at a given temperature in proportion to its maximum
water holding capacity.
Relative Humidity and temperature are the most
important factors determining the storage life of seeds.
Seeds attain a specific and characteristic moisture
content when subjected to given levels of atmospheric
humidities.
This characteristic moisture content called equilibrium
moisture content.
25. Equilibrium moisture content for a particular kind of
seed at a given Relative Humidity tends to increase as
temperature decreases.
Thus the maintenance of seed moisture content
during seed germination and storage is a function of
relative humidity and to a lesser extent of
temperature.
At equilibrium moisture content there is no net gain
or loss in seed moisture content.
26. C. Jensen (1941) treated seeds of cauliflower by exposing
them to a quartz-lamp and a sollux-lamp together, with full
strength for one hour at a distance of 1 m from the lamps.
Following this treatment the seeds were stored in glass
containers plugged with an ordinary cork or a paraffin cork.
The light-treated seeds maintained a higher germination %
over a period of eight years than untreated seeds.
Light treatment not only extended the life span of fresh
seeds, but also increase the germination capacity and vigour
of seeds,
27. Clayton (1931) found that treatment of vegetable seeds
with mercuric chloride, liquid organic mercurials , or hot
water, greatly shortened the life of vegetables.
Cotton-seed may be treated with organic mercury dusts
at any time after harvest and thereafter stored for
periods of up to seventeen months without injurious
effects resulting from the treatment and without
decreasing the beneficial effects of the treatment in
increasing seed viability and yield.(Miles, 1939, 1941)
28. Increase in O2
pressure decrease the period of
viability.
N2
and CO2
atmosphere will increase the storage
life of seeds.
Gaseous exchange is directly related to moisture
content of the seed and temperature at which it is
stored.
Gas durinG
storaGe
29. The activity of all these organisms can lead to damage resulting in
loss of viability.
Treated seeds with fungicides can be stored for longer periods.
Fumigation to control insects will also help in longer period of
storage.
Fumigants - methyl bromide, hydrogen cyanide, ethylene
dichloride, carbon tetra chloride, carbon disulphide naphthalene
and aluminimum phosphine.
Weevils, flour beetles, or borers are rarely active below 8% moisture
content and 18- 20°C, but are increasingly destructive as the
moisture content rises to 15% and temperature to 30-35°C.