1)Name the forces that maintain a transportational stream
2)Describe 4 environmental factors and 4 structural factors affecting the rate of transpiration
3)What is the strengthening tissue in;
a)cell wall
b)Xylem vessels
c)Tracheids
4)Give the function of the following;
a)Pith
b)Cambium
c)Cortex
5)Names two hormones that are responsible for;
a)Leaf fall
b)Parthenocarpy
c)Apical dominance
d)Breaks seed dormancy
6)Name 3 ways of naturally breaking seed dormancy
7)Name 5 causes is seemed dormancy
8)Name 5 ways of breaking seed dormancy
9)Why is seed dormancy important.
10)Give factors affecting germination and explain
11)Differentiate between secondary and primary growth.
1) The forces that maintain a transportation stream in plants are cohesion, adhesion, and tension.
2) Four environmental factors affecting the rate of transpiration are temperature, humidity, wind speed, and light intensity. Four structural factors affecting the rate of transpiration are stomatal density, stomatal size, cuticle thickness, and presence of trichomes.
3) a) The strengthening tissue in the cell wall is cellulose.
b) The strengthening tissue in xylem vessels is lignin.
c) The strengthening tissue in tracheids is lignin.
4) a) The pith functions as a storage tissue, storing water and nutrients.
b) The cambium is responsible for secondary growth in plants, producing new xylem and phloem cells.
c) The cortex is a region in the stem or root that functions in nutrient storage and support.
5) a) The hormone responsible for leaf fall is abscisic acid (ABA) or ethylene.
b) The hormone responsible for parthenocarpy is auxin.
c) The hormone responsible for apical dominance is auxin.
d) The hormone responsible for breaking seed dormancy is gibberellin.
6) Three ways of naturally breaking seed dormancy are scarification (physical damage to the seed coat), stratification (exposure to cold temperatures), and ingestion by animals which may expose the seed to digestion conditions.
7) Five causes of seed dormancy are the presence of hard seed coats, chemical inhibitors, embryo dormancy, dormant embryos that need specific environmental cues to germinate, and physiological dormancy.
8) Five ways of breaking seed dormancy are scarification (mechanical or chemical treatment to weaken the seed coat), stratification (exposing seeds to cold temperatures), soaking in water or acid, exposure to smoke or fire, and exposure to light.
9) Seed dormancy is important for the survival and dispersal of plants. It allows seeds to delay germination until optimal conditions are present, preventing premature germination and increasing the chances of successful establishment.
10) Factors affecting germination include water availability, oxygen availability, temperature, light, and the presence of germination inhibitors or promotors. Water and oxygen are needed for metabolic processes, temperature affects enzyme activity, light can stimulate or inhibit germination depending on the plant species, and certain chemicals can either promote or inhibit germination.
11) Primary growth refers to the growth of plant tissues in length, mainly occurring at the apical meristems (tips of roots and shoots). Secondary growth refers to the growth of plant tissues in girth, mainly occurring at the lateral meristems (vascular cambium and cork cambium). Primary growth results in the elongation of plant organs, while secondary growth results in the thickening of stems and roots.
1) The forces that maintain a transportational stream are cohesion and adhesion. Cohesion refers to the attraction between water molecules, which causes them to stick together. Adhesion refers to the attraction between water molecules and the walls of the xylem vessels or tracheids.
2) Environmental factors affecting the rate of transpiration include temperature, humidity, wind, and light intensity. Higher temperatures generally increase the rate of transpiration, while high humidity reduces it. Wind can enhance transpiration by removing moisture from the leaf surface, and light intensity can also affect transpiration rates.
Structural factors affecting the rate of transpiration include the number and size of stomata, presence of cuticle, thickness of leaf epidermis, and internal structure of the leaf. The number and size of stomata determine the surface area available for transpiration. A thicker cuticle or thicker epidermis can reduce transpiration by acting as a barrier to water loss. Finally, the internal structure of the leaf, such as the presence of specialized cells like palisade mesophyll, can affect transpiration rates.
3) a) The strengthening tissue in the cell wall is cellulose.
b) The strengthening tissue in xylem vessels is lignin.
c) The strengthening tissue in tracheids is also lignin.
4) a) The pith is the central region of a stem or root that consists of parenchyma cells. It functions in storage and support.
b) The cambium is a layer of meristematic tissue in between the xylem and phloem of a stem. It is responsible for secondary growth, producing new xylem and phloem cells.
c) The cortex is the outer layer of cells in roots and stems that provides support and stores carbohydrates.
5) a) The hormone responsible for leaf fall is ethylene.
b) The hormone responsible for parthenocarpy (the development of seedless fruits) is auxin.
c) The hormone responsible for apical dominance (the inhibition of lateral bud growth) is auxin.
d) The hormone responsible for breaking seed dormancy is gibberellin.
6) Three ways of naturally breaking seed dormancy include exposure to cold temperatures (stratification), exposure to fire or smoke (scarification), and digestion by animals (after ingestion, the seeds may be released in a suitable environment).
7) Five causes of seed dormancy are hard seed coat, chemical inhibitors, immature embryo, double dormancy, and physical dormancy caused by impermeable seed coats.
8) Five ways of breaking seed dormancy include scarification (mechanical or chemical treatment to break the seed coat), stratification (exposing seeds to cold temperatures), soaking in water (for seeds with impermeable seed coats), exposure to light or heat, and aging (allowing the seed to naturally mature over time).
9) Seed dormancy is important because it allows seeds to survive adverse conditions (such as drought or cold temperatures) and delay germination until more favorable conditions are present. This ensures the seeds have a better chance of survival and successful establishment.
10) Factors affecting germination include water availability, temperature, light, oxygen, and seed coat permeability. Seeds need sufficient water to initiate metabolic processes and activate enzymes for germination. Temperature affects the rate of germination, with different species having optimum temperature ranges. Some seeds require light for germination, while others require darkness. Oxygen availability is crucial for the respiration process during germination. Seed coat permeability determines whether water and gases can penetrate the seed coat and reach the embryo.
11) Primary growth refers to the vertical growth of plants, primarily in length, produced by the apical meristem at the tips of the shoots and roots. Secondary growth, on the other hand, refers to the lateral growth of plants, primarily in girth or width, produced by the lateral meristem called cambium. Primary growth is responsible for the increase in height, while secondary growth leads to the thickening of stems and roots.