几植物保护专业英语

2021年1月24日发(作者：obay)

Plant and Disease






Plants make up the majority of the earth's living environment as trees
，
grass
，
flowers
，
and so on. Directly or indirectly
，
plants also make up all the food
on which humans and all animals depend. Even the meat
，
milk
，
and eggs that we
and other carnivores eat come from animals that depend on plants for their food.
Plants are the only higher organisms that can convert the energy of sunlight into
stored
，
usable chemical energy in carbohydrates
，
proteins
，
and fats. All animals
，
including humans
，
depend on these plant substances for survival.




Plants, whether cultivated or wild
，
grow and produce well as long as the soil
provides them with sufficient nutrients and moisture
，
sufficient light reaches their
leaves
，
and the
temperature
remains
within
a
certain

”
range.
Plants
，
however
，
also get sick. Sick plants grow and produce poorly, they exhibit various
type of symptoms
，
and often parts of plants or whole plants die. It is not known
whether diseased plants feel pain or discomfort.




The agents that cause disease in plants are the same or very similar to those
causing disease in human, and animals. They include pathogenic microorganisms,
such
as
viruses,
bacteria
，
fungi
，
protozoa
，
and
nematodes
，
and
unfavorable
environmental conditions
，
such as lack or excess of nutrients
，
moisture
，
and light
，
and
the
presence
of

toxic
chemicals
in
air
or
soil.
Plants
also
suffer
from
competition with other
，
unwanted plants
（
weeds
）
，
and
，
of course they are often
damaged by attacks of insects. Plant damage caused by insects
，
humans
，
or other
animals is not usually included in the study of plant pathology.


Plant pathology is the study of the organisms and of the environmental factors
that
cause
disease
in
plants;
of
the
mechanisms
by
which
these
factors
induce
disease
in
plants
；
and
of
he
methods
of
preventing
or
controlling
diseased
reducing the damage it causes. Plant pathology is for plants largely what medicine
is for humans and veterinary medicine is for animals. Each discipline studies the
causes
，
mechanisms
，
and control of diseases affecting the organisms with which
it deals
，
i. e.
，
plants
，
humans
，
and animals, respectively.


Plant pathology is an integrative science and profession that uses and combines
the basic knowledge of botany
，
mycology
，
bacteriology
，< br>virology
，
nematology
，
plant
anatomy
，
plant
physiology
，
genetics
，
molecular
biology
and
genetic
engineering
，
biochemistry
，
horticulture
，
ag ronomy
，
tissue culture
，
soil science
，
forestry
，
chemistry
，
physic s
，
meteorology
，
and many other branches of science.
Plant
pathology
profits
from
advances
in
any
one
of
these
sciences
，
and
many
advances in other sciences have been made in attempts to solve plant pathological
problems:




As
a
science
，
plant
pathology
tries
to
increase our
knowledge
about plant
diseases.
At
the
same
time
，
plant
pathology
tries
to
develop
methods
，

equipment
，
and
materials
through
which
plant
disease
can
be
avoided
or
controlled.
Uncontrolled
plant
disease
may
result
in
less
food
and
higher
food
prices
or
in
food
of
poor
quality.
Diseased
plant
product
may
sometimes
be
poisonous
and
unfit
for
consumption.
Some
plant
diseases
may
wipe
out
entire
plant
species
and
many
affect
the
beauty
and
landscape
of
our
environment.
Controlling
plant
disease
results
in
more
food
of
better
quality
and
a
more
aesthetically
pleasing
environment
，
but
consumers
must
pay
for
costs
of
materials
，
equipment, and labor used to control plant diseases and
，
sometimes
，
for other less evident costs such as contamination of the environment.




In the last 100 years
，
the control of plant diseases and other plant pests has
depended
increasingly
on
the
extensive
use
of
toxic
chemicals
（
pesticides)
．

Controlling
plant
diseases
often
necessitates
the
application
of
such toxic chemicals not only on plants and plant produce that we consume
，
but
also
into
the
soil
，
where
many
pathogenic
microorganisms
live
and
attack
the
plant
roots. Many
of
these chemicals have
been shown
to be toxic
to nontarget
microorganisms
and
animals
and
may
be
toxic
to
humans.
The
short-and
long-term
costs
of
environmental
contamination
on
human
health
and
welfare
caused by our efforts to control plant diseases
（
and other pests
）
are difficult to
estimate.
Much
of
modern
research
in
plant
pathology
aims
at
finding
other
environmentally friendly means of controlling plant diseases. The most promising
approaches
include
conventional
breeding
and
genetic
engineering
of
disease-resistant
plants
，
application
of
disease- suppression
cultural
practices
，
RNA-and
gene-silencing
techniques
，
of
plant
defense- promoting
nontoxic
substances
，
and
，
to
some
extent
，
use
of
biological
agents
antagonistic
to
the
microorganisms that cause plant disease.




The challenges for plant pathology are to reduce food losses while improving
food quality and
，
at the same time
，
safeguarding our environment. As the world
population
continues
to
increase
while
arable
land
and
most
other
natural
resources
continue
to
decrease
，
and
as
our
environment
becomes
further
congested
and
stressed
，
the
need
for
controlling
plant
disease
effectively
and