The Life Cycle of A Canola Seed

What is Canola?

Overview of Canola

Canola is a relativly newly developed crop that is a major source of income and profiibilty for Individuals involved in the agricultural buisness. Developed by scientists in the 1970's, this new crop falls in the botanical family (Brassica Genus). It's name originated from Canada and oil (ola). Canola has many uses such as oil for cooking, feed for agricultural animals as well as a great marinade.

The History of Canola in-depth

The success and Importance of Canola

Chemical Properties Of Canola

Canola being water soluble is not water soluble. Like most oils that are edible, Canola is made up of fatty acids. The majority of Canola oil fatty acid is triglycerides, which is made up of one glycerol molecule that is attached to three fatty acid molecules. There are different types of fatty acids with differing amounts of carbon atoms, the predominant type contains 18 carbon molecules. These 18 carbon molecules are called, octadecanoic fatty acids. Then these carbon fatty acids can be further brokendown into subtypes. The predominant one in canola oil is oleic acid with smaller amounts of linolenic acid. Canola retains a small proportion of linolenic acid to help with the flavour of fried foods, related to it's oxidation, which is the need for flavour in food that are fried. The linolenic acid confers stability in frying, and also adds to thr flavour.

Chemical Properties of Canola

Physical Properties of Canola

Like the vicosity of most vegatable oils, canola's oil viscosity decreases along with a rise in temperature, as does it's density. The smoke point of canola is about 200 degrees celcius. the smoke point is defined as when a wisp of smoke is created continuiosly by heating to a defined temperature. The flash point of when the heated oil ignites is approximately 275 degrees celcius. Its resistance to developing sediment, when cooled to between o and 4 degrees celcius is called the cold test. Canola oil does not develop sediment when cooled for 15 hours at these temperatures. The melting point for canola oil is about 10 degrees celcius. There is a correlation between the melting point of cooking oils and chloresterol. Cooking oils and and fats with a lower melting point are generally considered healthier. Lard, example, has a melting point of 33 degrees celcius.

Germintation

Germintation is the first stage in the development of the seed. Water absorption is the first step in germination, the seed recieves water from the soil. It is influenced by the dillution of inorganic salts and as well as other organic substances within the soil. Many seeds fail to absorb enough water, do to the salt concentration within the water being to high. Cellular respiration is the next step as the seed needs enough oxygen to provide enough energy for germination. During the absorption of water, many enzyme systems are engaged in the embryo which leads to the breakdown of protien. These are then used to rebuild nutrients such as protiens that are necessary for embryo growth and ultimatly the emergence of the root. The root anchors the seed, pushing seed leaves or cotyledons through into the soil. Some factors that influence germination are soil moisture, salt content of the water, seed size and soil microrganisms.

Germantion

Leaf Development: Stage 1

Up to two weeks after seeding, a short stem evolves. The cotyledons at the top of the hypocotyl, turn green and provide nourishment to the plant. The growing point of canola is above the soil between the two cotyledons. Canola's root length is up to 5cm after exposure as they run on a tap root system.This root growth is caused by cell division. The main purpose of the roots is to absorb water and nutrients from the soil and send them up the stem. The stem and root correlate as they will adjust their size for one another for better balance.

After the first leaves are developed, the plant uses a rosette with aged leaves to devlop its appearance. Through the rosette growth stage the stem length remains the same but it's thickness increases. Canola leaves are influenced by the plant's overall sink compacity. Rapid root growth encourages seed yeild. The more leaf area exposed to the sun, the more dry matter can be produced by the seed. The leaves of canola only contribute to a small part of photosynthesis.

Leaf Development

Growth: Stage 2

Growth stage 2 is really quite simple. It is the development of side shoots also known as (tillering)

Growth: Stage 2

Stage 3: Stem Elongation

During stem elongation, sunlight and air is exposed to the leaves through the stem of canola. The canola seed and plant through seed and plant growth contributes to photosynthesis. The growth of the stem progresses in phases. The first step overlaps leaf development. When the stem reaches it's max length it overlaps with flower development then reaches it peak at peak flowering. As the stems grow, the roots only continue to go deeper.

The height and thickness of the stem is influenced by may factors such as plant population,moisture and the vertility of the soil. There are many varities of stems as different growing condition influence the many different aspects of the stem. Plant's in thin-crop are more resitant to lodging as well have thicker stems and vise-versa. Lodging creates an ideal enviorment for dieases such as sclerotinia. Through disease the capacity of the pods in terms of photsynthesis is limited or damaged, greatly affecting the yields.

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Growth Stage 4

This growth stage is considered irrelevant in terms of canola development and managment but is important in terms of some vegtables such as broccoli.

Growth Stage 5: Inflorescence Emergence

In this stage, the Canola goes from buds covered in leaves to buds with yellow petals visible, but with the buds still not open. The main stem of the plant is about 30%-60% of it's final length. Maximum leaf area is obtained just prior to flowering at the end of this growth phase, and these upper leaves are maintained well into the flowering cycle. The lower leaves on the stem start to disappear. The upper leaves are the main source of nutrients for the developing bud and stems of the canola plant. The fast growth of the large leaf allows the pod to set and is influential in early seed development. Important factors in developing and maintaining the large leaf area beyond flowering are the preperation of the seedbed, along with moisture levels, temperature and adequate nutrition of the developing plant. If these are optimized then uniform growth and emergence are seen. The large leaf area becomes less important as the flowering proceeds and this is seen in the surface area declining and has the added benifit as it declines, decreasing seed loss and increased yield.

Stage 6: Flowering

This stage is characterized from buds opening, producing yellow flowers, the main raceme lengthening, the plant fully flowering, and the majority of the petals falling off the canola plant. This stage is most recognizable to the most causal observer due to large swaths of land being covered in this yellow flower, and if you are prone to Canola allergies, this is the time to avoid being near the fields of yellow.

The yellow flowers are pivotal in absorbing and reflecting solar radiation. The flowers form a layer about the length of a ruler (3ocm). They have been shown to absorb or reflect between 50-60% of the incoming solar radiation, that could be used for photosynthesis. The reason for the deceased leaf surface in this phase of growth is the blockage of solar radiation by the petals of the plants. Senescence is the result in the grean leaves.

Growth Stage 7: Development of The Seed

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This stage of growth in the Canola Plant sees the majority of the pods which contain seeds, reach their final size. In the middle of flowering, the lower pods are developing first. The stem is the major supplier of nutrtition for the plant, with a reduced amount of nutrtition coming from the leaves. Competition exists between the flower, pods and branches for nutrtition. Earlier developing pods have an advantage over later developing pods. Flowering continues on secondary branches, having stopped on the main stem. Seed growth at this stage depends on the stem and pod walls for food.

In the first two weeks of seed growth, the seed coat enlarges until the seed is almost full size. It resembles a water-filled balloon. The embryonic growth of the seed begins now. The seed water in the seed coat is displaced, seed weight increases. This growth is optional when temperature and soil moisture is in ideal ranges. excesses or decreases in either result in smaller pods with lighter seeds.

Growth Stage 8: Ripening

The leaves of the canola plant have turned yellow and fallen off the plant. The seeds now rely on the pod walls for nutrition, however, the stem till retains a lesser role. It has been 35-45 days since the flowers opened and seed filling is finalized . The seed appears green and firm. There is enough protien and oil for germination and seedling growth in the future within these seeds. The pods and stems turn yellow and become brittle.

At the stage where seeds in the lower have turned green, most of the leaves on the plant have yellowed and fallen from the plant. The pod walls have become the major source of food although the stem is still important. The pods,besides beig major food producers, are also major food users from other sources for seed development.

About 35 to 45 days after the flower opens, seed filling is complete. The firm green seed had adequate oil and protien reserves to support future germentation and seedling growth. The stems and pods turn yellow and progressively become brittle as they dry. Immature seeds contain about 40% moisture and reduce 2-3% a day. At 60 days after flowering started, the seeds have fully ripened and changed color. Both the seed coat and seed change color. Mature seeds are black or yellow in color. The number of pods per plant and seeds per pod is determined at flowering. However, seed weight and filling can still be influenced by suboptimal temperature and moisture conditions, disease or insect damage.

Growth Stage 9: Senescence

Senescence occures when all the pods have changed in color, and the plant dies. The mature pods split and release the seed and the seed is lost or harvested.