Explanation of events that occur plants along the growth curve

(a) Name the different stages of plant growth curve

• A – B: lag phase/establishment stage
• B – C: logarithmic stage/rapid growth stage
• C – D: steady stage/maturation stage
• D – E : decline stage/senescence

(b) State four physiological events that occur between A and B (04marks)

• Hydrolysis of storage food material
• Synthesis of enzymes, nucleic acids, structural proteins
• Respiration to provide energy for cellular activities
• Glucose and amino acids are translocated from the storage centre (endosperm or cotyledon) of the seed to the growing regions of the embryo.
• Cell division, elongation and differentiation leads to immergence of a seedling from a seed.

(c) Account for rapid increase in dry matter yield between B and C (02marks)

• Rapid cell multiplication due to presence of many cells
• Absence of diseases and other environmental resistance.
• Absence of pollutants

(d) Suggest two causes of the decline in dry matter yield between A and E

High-rate cell death caused

• Accumulation of waste/toxic materials in plant that inhibit growth
• Diseases
• Predators/parasite
• Lack of water towards dry season

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