Seed germination and plant growth

It is known that seed size affects the rate of germination. Increased germination rates may be related to more stocks available in large seeds compared to medium or small seeds (Ekpo, 2004).

Plant growth

Plant growth is a biological process during which a quantitative increase in matter occurs. For the growth of the plant is important breathing process through which they obtain the necessary energy. Plant growth is associated with increasing cell volume and division

Plant growth is influenced by the following factors:

• Temperature – has an obvious effect on growth. If it increases by 10 degrees, the growth will be double intensified. We distinguish temperature minimum (growth starts, approx. 5˚C), optimum (growth is greatest, approx. 25˚C) and maximum (growth stops, approx. 30–37˚C).

• Water – physiological changes (e.g. wilting) are evident on a plant that is found in an environment with an excess or lack of water.

• Light – plant root growth is not dependent on light. On the contrary, the growth of above-ground parts of plants is dependent on light. The most active areas of the radiation spectrum that most affect the growth and development of plants are the areas of red radiation, in particular the wavelengths 660 nm (weak red light) and 730 nm (dark red light) and blue radiation with peaks 370, 450 and 480 nm.

• Substrate – for optimal growth, the plant needs to extract nutrients from the soil (e.g. nitrogen, phosphorus, potassium, magnesium, calcium, etc.).

• Earth gravitation – causes the branches and stems to bend and grow horizontally

• Electricity and magnetism – in plants, electrical potentials are created that affect e.g. for the distribution of phytohormones and thereby affect the growth and formation of the plant.

Classification of plant body organs

By function we can classify the plant organs into vegetative and generative organs. Vegetative organs include root, stem and leaves, these organs ensure the life of the plant. They provide various functions – nourishing, growth, respiratory, protective, support and transport.

The generative organs of the plant include flowers, seeds and fruits. Their role is to ensure the reproduction and conservation of the species. Further, we briefly characterize the individual plant organs.

• Root – an underground organ. We distinguish the root cap (not found in aquatic plants and parasites), the skin (protective and absorption function; it covers the root surface, creates root hairs), the primary cortex and the central cylinder (the complex of tissues). The root grows in length but also in width.

• Stem – the radial section of the stem distinguishes the skin (covers the entire surface of the stem), the primary bark (between the skin and the central cylinder) and the central cylinder with vascular bundles

• Leaf – an organ of limited growth that has photosynthetic, vaporizing and nutritional functions. On the leaf we recognize the leaf blade (the main part of the leaf, the skin with vents on the surface, covers and protects the inner mesh of the leaf and directs the light rays), the stem and the vagina. On the letter we distinguish cheeks and reverse (bifacial sheet). However, there are also leaves that have the same sides on both sides (eg tulip). Especially on the leaf of the leaf there is leafy veins (veins and veins). We recognize parallel vein, vertex parallel, feathered, palm and legged vein (Sekerka, Múdry, 2005).

B) divided single leaf shapes

C) shapes of folded leaves

• Flower – an eruptive sprout of limited growth that is involved in the sexual reproduction of plants. The flower consists of a flower bed (an enlarged part of the main or side stalk – the flower is differentiated here; there are placed flower covers, stamens and fruit trees), flower covers (they can be indistinguishable to form a flower) – all the petals are the same color ( tulip, narcissus) or distinction – calyx – green psoriasis and crown – colored psoriasis), stamens (male part of the flower, which consists of thread, pollen and pollen grains) and piston (female part of the flower, distinguishing the testicle, forehead and loved ones).

• Fruit – arises from the testicle or the entire piston. Its function is to protect and coat the eggs while nourishing them. The fruit is divided into flesh (berry – blueberry, stone fruit – plum, pomiferous fruit – apple tree), dry poppy (bladder – peony, teat – bean, purslane – horseradish, capsule – primrose) and dry non-cracked (nut – hazel) – dandelion, grain – cereal), frosting and brittle fruits (biped – carrots, hard – nettle, pastry – fire) and seed fruits (cone – cones, seed stone – ginkgo).

Fruit Types (seeds black). A–E, succulent indehiscent fruit: A, drupe, 1-seeded (in T.S.); B, drupe, 5 seeded (in T.S.); C, pome (in L.S.); D, superior berry (in L.S.); E, inferior berry (in L.S.); F–K, dry dehiscent fruits; F, many-seeded follicle; G, follicle with 2-winged seeds; H, schizocarp; I, legume or pod; J, lomentum; K, siliqua; L–P, capsules: L, loculicidal capsule; M, septicidal capsule; N, poricidal casule; O, circumsciss capsule; P, schizocarp capsule; Q–U, dry indehiscent fruits, with sections showing position of seed: Q, achene from a superior ovary; R, achene from inferior ovary with apical pappus; S, caryopsis; T, nut; U, samara; V–X, aggregate fruits in L.S.: V, rose ‘hip’, individual fruits drupelets; W, strawberry, individual fruits achenes; X, blackberry, individual fruits drupelets; Y & Z, multiple fruits in L.S.: Y, syconium or ‘fig’; Z, tsyncarp. Picture source: http://plantnet.rbgsyd.nsw.gov.au

Plant transition from vegetative to reproductive phase

It is a transition to the flowering phase, which begins with the differentiation of the foundations of the flowering organ (Sekerka, Múdry, 2005). In order to start flowering, the plant needs certain external conditions, namely the appropriate temperature and light. Some second plants (eg, crops) require the so-called flowering before flowering. winter cold (temperatures above zero to + 15 ˚C).

The length of day, or the length of daylight, is also important in order to promote flowering. According to it, we can divide the plants into 3 categories:

A) Plants of a long day – flowering in summer when the days are long, e.g. cereals, carrots, spinach, etc., lower limit 10–14 hours.

B) Plants of a short day – flowering in spring or autumn months when the days are short, e.g. sunflower, chrysanthemum, soybean, etc., upper limit 10-14 hours

C) Neutral plants – flowering irrespective of the length of illumination, e.g. corn, nutmeg.