biology form 4 chapter 6

5/26/2018 Biology Form 4 Chapter 6

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6. 14 TECHNOLOGY IN FOOD PRODUCTION

What is food production ?

A process of generating refined, processed newly-made products thatcan be consumed by living things, which usually include man and

animals.types of food production

Farming Ranching Hunting Fishing

6.14.1 quality and quantity of food

The need to improve the quality and quantity of food

The population of Malaysia increase year by year The production of food need to increase too So that the food contains more nutrients,and are tasty for us to

consume


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Efforts to diversify our food production

diversify to give varietyWe must diversify our food production to increase the health of Malaysians.To have a healthy body, we have to take a balanced diet. Balanced diet is

the food that contains all types of nutrient and is consumed in the right

proportion.

Our government has done many kinds of ways to improve the eating habit

of Malaysians, including campaigns. A few of these campaigns are

encouraging Malaysians to consume more :-

a) ulam ( a form of local salad )

Ulam consists of various plant eaten raw, and they are rich in

vitamins, minerals and dietary fibres.

Example : onions, cucumber, spearmint, pennywort (pegaga), four-

angle beans (kacang botol), petai, jantung pisang and many more.

b)mushrooms (cendawan)

The government encourages the cultivation of many edible

mushrooms because they are rich in proteins.


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Example ; shiitake mushroom, oyster mushroom, button mushroom

and straw mushroom.

Mushrooms are low in calories, have no cholesterol, free of fat and

also sodium, and are rich in essential minerals.

c) fresh water fishes- has salinity less than 0.05%. it can be more healthyto consume this type of fish compared to salt water fish.

Freshwater fishes are very nutritious, containing proteins, low in fat,

rich in vitamin, and minerals like phosphorus, calcium and iron.

Examples : giant gourami, three-spot gourami, thai silver barb and

sultan fish.

d) rabbit meat source of high quality protein

Rabbit meat is very nutritious, very rich in proteins and minerals.

It can also replace red meat and can reduce the risk of contracting

coronary heart diseases.


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Methods in food production

1.direct seeding

what is direct seeding?

Direct seeding establishes trees, shrubs, and understorey plants by

sowing seed directly onto the site to be revegetated. Whether

sowing by machine or by hand, good site preparation and effective

weed control are essential for success.

Advantages of direct seeding

Direct seeding is much cheaper (10 - 20% or less of the cost ofplanting tubestock), and requires minimal labour.

Existing farm equipment can be used. Alternatively, severalorganisations and landcare groups have direct seeding machines for

hire.

Higher plant density after germination provides better shelter to newseedlings and reduces weed competition. It also allows natural

selection to sort out the stronger from the weaker plants without

creating gaps to be replanted.

Plants are able to self select suitable establishment sites within therevegetation area, particularly if a mixture of species is sown.

The plants are usually healthier and have stronger, deeper rootsystems because they are not transplanted and there is no

disturbance to root growth. This enables plants to be more tolerant of

stressful conditions such as pest attack and drought.

Final plant cover is random, and looks more natural than planting. Little maintenance is required after plants are established, apart from

ongoing weed control for at least the first season (which ensures no

watering).


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FIGURE 1: GOOD WEED CONTROL IS ESSENTIAL FOR CREATING A

RESERVOIR OF SOIL MOISTURE FOR SEEDLING GROWTH, AND TO

PREVENT COMPETITION FOR LIGHT AND NUTRIENTS

Disadvantages

The disadvantages of direct seeding are:

Direct seeding is limited to plants that grow readily from seed(though research is increasing this range).

A large amount of seed is required. Hence, if only minimal seed isavailable for a particular species, it may be better to raise seedlings

for that species in a nursery.

Plants germinating under field conditions are extremely vulnerable.Frosts, spring droughts, or flooding of the sowed area can

dramatically reduce seedling establishment.

The initial density of plants is harder to control. This may createundesirable spacings for quality timber production, but can be

overcome by spot sowing.


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Uses for direct seeding

Direct seeding is very suited to revegetating large areas for:

shelterbelts and wildlife habitat; linear sections alongside roads, railways, and streams; control of groundwater recharge and erosion; and firewood, fodder crops, and other harvested products.

2. hydroponics

What is hydroponics ?

A subset of hydroculture and is a method of growing plants using mineral

nutrient solutions, in water, without soil. Terrestrial plants may be grown

with their roots in the mineral nutrient solution only or in an inert medium,

such as perlite, gravel, mineral wool, expanded clay pebbles or coconut

husk.

The shoot system of the plant is supported by a framework, and the root

system is immersed in a nutrient solution for the plant to grow.

The nutrient solution provides the exact nutrients plants need, so they can

develop and grow.

Air is bubbled through the nutrient solution ( aeration ) to make sure that

the roots have sufficient oxygen for respiration.

Advantages

Some of the reasons why hydroponics is being adapted around the world

for food production are the following:


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No soil is needed for hydroponics The water stays in the system and can be reused - thus, a lower water

requirement

It is possible to control the nutrition levels in their entirety - thus,lower nutrition requirements No nutrition pollution is released into the environment because of the

controlled system

Stable and high yields Pests and diseases are easier to get rid of than in soil because of the

container's mobility

Ease of harvesting

No pesticide damage Plants grow healthier It is better for consumption

Disadvantages

Without soil as a buffer, any failure to the hydroponic system leads to rapidplant death. Other disadvantages include pathogen attacks such as damp-

off due to Verticillium wilt caused by the high moisture levels associated

with hydroponics and over watering of soil based plants. Also, many

hydroponic plants require different fertilizers and containment systems.

Techniques

Solution culture

Solution culture does not use a solid medium for the roots, just the

nutrient solution. The two main types of solution cultures are static

solution culture, and continuous-flow solution culture.


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Static solution cultureIn static solution culture, plants are grown in containers of nutrientsolution, such as glass Mason jars (typically, in-home applications),

plastic buckets, tubs, or tanks.

The solution is usually gently aerated but may be un-aerated. If un-

aerated, the solution level is kept low enough that enough roots are

above the solution so they get adequate oxygen.

A hole is cut in the lid of the reservoir for each plant. There can be

one to many plants per reservoir. Reservoir size can be increased as

plant size increases. A home made system can be constructed from

plastic food containers or glass canning jars with aeration provided by

an aquarium pump, aquarium airline tubing and aquarium valves.

Clear containers are covered with aluminium foil, butcher paper, black

plastic, or other material to exclude light, thus helping to eliminatethe formation of algae.

The nutrient solution is changed either on a schedule, such as once

per week, or when the concentration drops below a certain level as

determined with an electrical conductivity meter.

Whenever the solution is depleted below a certain level, either water

or fresh nutrient solution is added, A Mariotte's bottle, or a float

valve, can be used to automatically maintain the solution level.


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In raft solution culture, plants are placed in a sheet of buoyant plastic

that is floated on the surface of the nutrient solution. That way, the

solution level never drops below the roots.

Continuous-flow solution cultureIn continuous-flow solution culture, the nutrient solution constantly

flows past the roots. It is much easier to automate than the static

solution culture because sampling and adjustments to the

temperature and nutrient concentrations can be made in a large

storage tank that has potential to serve thousands of plants.

A popular variation is the nutrient film technique or NFT, whereby a

very shallow stream of water containing all the dissolved nutrients

required for plant growth is recirculated past the bare roots of plants

in a watertight thick root mat, which develops in the bottom of thechannel, has an upper surface that, although moist, is in the air.

Subsequent to this, an abundant supply of oxygen is provided to the

roots of the plants. A properly designed NFT system is based on using


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the right channel slope, the right flow rate, and the right channel

length.

The main advantage of the NFT system over other forms of

hydroponics is that the plant roots are exposed to adequate supplies

of water, oxygen, and nutrients.

In all other forms of production, there is a conflict between the

supply of these requirements, since excessive or deficient amounts of

one results in an imbalance of one or both of the others. NFT,

because of its design, provides a system where all three requirements

for healthy plant growth can be met at the same time, provided that

the simple concept of NFT is always remembered and practised.

The result of these advantages is that higher yields of high-quality

produce are obtained over an extended period of cropping. A

downside of NFT is that it has very little buffering against

interruptions in the flow, e.g., power outages. But, overall, it is

probably one of the more productive techniques.

The same design characteristics apply to all conventional NFT

systems. While slopes along channels of 1:100 have been

recommended, in practice it is difficult to build a base for channels

that is sufficiently true to enable nutrient films to flow without

ponding in locally depressed areas.

As a consequence, it is recommended that slopes of 1:30 to 1:40 are

used. This allows for minor irregularities in the surface, but, even with

these slopes, ponding and water logging may occur.


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The slope may be provided by the floor, or benches or racks may hold

the channels and provide the required slope. Both methods are used

and depend on local requirements, often determined by the site and

crop requirements.

As a general guide, flow rates for each gully should be 1 liter per

minute. At planting, rates may be half this and the upper limit of 2

L/min appears about the maximum.

Flow rates beyond these extremes are often associated with

nutritional problems. Depressed growth rates of many crops have

been observed when channels exceed 12 metres in length. On rapidly

growing crops, tests have indicated that, while oxygen levels remain

adequate, nitrogen may be depleted over the length of the gully.

As a consequence, channel length should not exceed 1015 metres. In

situations where this is not possible, the reductions in growth can be

eliminated by placing another nutrient feed halfway along the gully

and reducing flow rates to 1 L/min through each outlet.

A commercially available type of continuous flow system


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3. AEROPONICS

WHAT IS AEROPONICS ?

The process of growing plants in an air or mist environment without the use

of soil or an aggregate medium (known as geoponics).

Types of aeroponics

Low-pressure units

In most low-pressure aeroponic gardens, the plant roots are suspended

above a reservoir of nutrient solution or inside a channel connected to a

reservoir. A low-pressure pump delivers nutrient solution via jets or by

ultrasonic transducers, which then drips or drains back into the reservoir. As

plants grow to maturity in these units they tend to suffer from dry sections

of the root systems, which prevent adequate nutrient uptake. These units,because of cost, lack features to purify the nutrient solution, and

adequately remove incontinuities, debris, and unwanted pathogens. Such

units are usually suitable for bench top growing and demonstrating the

principles of aeroponics.

High-pressure devices

High-pressure aeroponic techniques, where the mist is generated by high-

pressure pump(s), are typically used in the cultivation of high value crops

and plant specimens that can offset the high setup costs associated with

this method of horticulture.


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Since the late 2000s, home indoor gardeners have had access to simple

high pressure aeroponic (HPA) systems at affordable prices.

High-pressure aeroponics systems include technologies for air and water

purification, nutrient sterilization, low-mass polymers and pressurizednutrient delivery systems.

Commercial systems

Commercial aeroponic systems comprise high-pressure device hardware

and biological systems. The biological systems matrix includes

enhancements for extended plant life and crop maturation.

Biological subsystems and hardware components include effluent controls

systems, disease prevention, pathogen resistance features, precision timing

and nutrient solution pressurization, heating and cooling sensors, thermal

control of solutions, efficient photon-flux light arrays, spectrum filtration

spanning, fail-safe sensors and protection, reduced maintenance & labor

saving features, and ergonomics and long-term reliability features.

Commercial aeroponic systems, like the high-pressure devices, are used for

the cultivation of high value crops where multiple crop rotations are

achieved on an ongoing commercial basis.

Advanced commercial systems include data gathering, monitoring,

analytical feedback and internet connections to various subsystems.


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Benefits of aeroponics for earth and space

Aeroponics possesses many characteristics that make it an effective and

efficient means of growing plants.

Less nutrient solution throughput

Plants grown using aeroponics spend 99.98% of their time in air and 0.02%

in direct contact with hydro-atomized nutrient solution. The time spent

without water allows the roots to capture oxygen more efficiently.

Furthermore, the hydro-atomized mist also significantly contributes to the

effective oxygenation of the roots. For example, NFT has a nutrient

throughput of 1 liter per minute compared to aeroponics throughput of

1.5 milliliters per minute.

The reduced volume of nutrient throughput results in reduced amounts of

nutrients required for plant development.

Another benefit of the reduced throughput, of major significance for space-

based use, is the reduction in water volume used. This reduction in water


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volume throughput corresponds with a reduced buffer volume, both of

which significantly lighten the weight needed to maintain plant growth. In

addition, the volume of effluent from the plants is also reduced with

aeroponics, reducing the amount of water that needs to be treated before

reuse.

The relatively low solution volumes used in aeroponics, coupled with the

minimal amount of time that the roots are exposed to the hydro-atomized

mist, minimizes root-to-root contact and spread of pathogens between

plants.

Greater control of plant environment

Aeroponics allows more control of the environment around the root zone,

as, unlike other plant growth systems, the plant roots are not constantly

surrounded by some medium (as, for example, with hydroponics, where the

roots are constantly immersed in water).

Improved nutrient feeding

A variety of different nutrient solutions can be administered to the root

zone using aeroponics without needing to flush out any solution or matrix

in which the roots had previously been immersed. This elevated level of

control would be useful when researching the effect of a varied regimen of

nutrient application to the roots of a plant species of interest. In a similar

manner, aeroponics allows a greater range of growth conditions than other

nutrient delivery systems. The interval and duration of the nutrient spray,

for example, can be very finely attuned to the needs of a specific plant

species. The aerial tissue can be subjected to a completely differentenvironment from that of the roots.

More user-friendly

The design of an aeroponic system allows ease of working with the plants.

This results from the separation of the plants from each other, and the fact


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that the plants are suspended in air and the roots are not entrapped in any

kind of matrix. Consequently, the harvesting of individual plants is quite

simple and straightforward. Likewise, removal of any plant that may be

infected with some type of pathogen is easily accomplished without risk of

uprooting or contaminating nearby plants.

More cost effective

Aeroponic systems are more cost effective than other systems. Because of

the reduced volume of solution throughput (discussed above), less water

and less nutrients are needed in the system at any given time compared to

other nutrient delivery systems. The need for substrates is also eliminated,

as is the need for many moving parts .

Use of seed stocks

With aeroponics, the deleterious effects of seed stocks that are infected

with pathogens can be minimized. As discussed above, this is due to the

separation of the plants and the lack of shared growth matrix. In addition,

due to the enclosed, controlled environment, aeroponics can be an ideal

growth system in which to grow seed stocks that are pathogen-free. Theenclosing of the growth chamber, in addition to the isolation of the plants

from each other discussed above, helps to both prevent initial

contamination from pathogens introduced from the external environment

and minimize the spread from one plant to others of any pathogens that

may exist.

21st century aeroponics

Aeroponics is an improvement in artificial life support for non-damaging

plant support, seed germination, environmental control and rapid

unrestricted growth when compared with hydroponics and drip irrigation

techniques that have been used for decades by traditional agriculturalists.


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Contemporary aeroponics

Contemporary aeroponic techniques have been researched at NASA's

research and commercialization center BioServe Space Technologies

located on the campus of the University of Colorado in Boulder, Colorado.Other research includes enclosed loop system research at Ames Research

Center, where scientists were studying methods of growing food crops in

low gravity situations for future space colonization.

In 2000, Stoner was granted a patent for an organic disease control

biocontrol technology that allows for pesticide-free natural growing in an

aeroponic systems.

Aeroponic bio-pharming

Aeroponic bio-pharming is used to grow pharmaceutical medicine inside of

plants. The technology allows for completed containment of allow effluents

and by-products of biopharma crops to remain inside a closed-loop facility.

As recently as 2005, GMO research at South Dakota State University by Dr.

Neil Reese applied aeroponics to grow genetically modified corn.

According to Reese it is a historical feat to grow corn in an aeroponic

apparatus for bio-massing. The universitys past attempts to grow all types

of corn using hydroponics ended in failure.

Using advanced aeroponics techniques to grow genetically modified corn

Reese harvested full ears of corn, while containing the corn pollen and

spent effluent water and preventing them from entering the environment.

Containment of these by-products ensures the environment remains safe

from GMO contamination.

Large scale integration of aeroponics

In 2006, the Ag University of Hanoi Vietnam in joint efforts with Stoner

established the postgraduate doctoral program in aeroponics. The


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university's Agrobiotech Research Center, under the direction of Dr. N.

Thach, is using aeroponic laboratories to advance Vietnam's minituber

potato production for certified seed potato production.

The historical significance for aeroponics is that it is the first time a nationhas specifically called out for aeroponics to further an agricultural sector,

stimulate farm economic goals, meet increased demands, improve food

quality and increase production.

Vietnam joined the World Trade Organization (WTO) in January 2007. The

impact of aeroponics in Vietnam will be felt at the farm level.

Aeroponic integration in Vietnam agriculture will begin by producing a lowcost certified disease-free organic minitubers, which in turn will be supplied

to local farmers for their field plantings of seed potatoes and commercial

potatoes. Potato farmers will benefit from aeroponics because their seed

potatoes will be disease-free and grown without pesticides. Most

importantly for the Vietnamese farmer, it will lower their cost of operation

and increase their yields.

4. tissue culture

What is tissue culture ?

The growth of tissues or cells separate from the organism. This is typically

facilitated via use of a liquid, semi-solid, or solid growth medium, such as

broth or agar.

Main principles of tissue culture

1. A piece of tissue, called explant is taken from the parent plant and cutinto small pieces.

2. The pieces of tissues are sterilized with dilute sodium hypochloritesolution to prevent the growth of pathogens ( bacteria, fungus ).


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3. Each sterile tissue piece is placed onto a growth medium( gelcontaining nutrient and growth regulators )

4. The tissue cells divide by mitosis to produce a mass of looselyarranged and undifferentiated cells called callus.

5. Callus is stimulated with shoot-stimulating hormones to formmultiple shoots.

6. The shoots are separated and each is placed in nutrient medium withroot-stimulating hormones to encourage rooting.

7. Once the roots grow, the plantlets (little plants) are planted in sterilecompost to grow.

biology form 4 chapter 6

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