To understand the techniques of growth analysis in fruit crops
Aim of the Experiment: To understand the various techniques for growth analysis in fruit crops.
Objective:
To study various techniques of growth analysis in fruit crops using growth parameters
such as Leaf Area Index (LAI), Relative Growth Rate (RGR), and Net Assimilation
Rate (NAR).
Apparatus
Required:
Leaf area meter or graph paper, weighing balance,
measuring scale, oven (for drying), calculator, sample plants (e.g., banana,
guava, papaya).
Theory:
Growth analysis is the quantitative study of growth
and productivity in plants over time. It involves calculating parameters that
reflect the efficiency of photosynthesis and biomass accumulation. Key indices
include:
Ø Leaf
Area Index (LAI): Ratio of total leaf area to the ground area it covers;
reflects the canopy density and potential for photosynthesis.
LAI
= Total Leaf Area / Ground Area
Ø Relative
Growth Rate (RGR): The increase in plant dry weight relative to its size over
time; indicates overall plant vigor.
RGR
= (W₂ - W₁) / (t₂ - t₁)
Ø Net
Assimilation Rate (NAR): The rate at which a plant accumulates dry matter per
unit of leaf area; measures photosynthetic efficiency.
NAR = (W₂ - W₁) / [(A₂ +
A₁)/2 × (t₂ - t₁)]
Where,
W₁, W₂ = Dry weight at time t₁ and t₂, A₁, A₂ = Leaf area at time t₁ and t₂
These indices help understand how effectively a plant
converts resources into biomass and are important in comparing varieties,
treatments, or environmental conditions.
Procedure:
i. Select 5–10 healthy and uniform plants of a chosen fruit crop.
ii. Tag the plants and note initial parameters (leaf area, dry weight).
iii. Measure leaf area using a leaf area meter or by tracing leaves on graph paper and counting squares.
iv. Carefully uproot plants without damaging the root system.
v. Separate leaves, stems, and roots.
vi. Dry the samples in a hot air oven at 70°C for 48–72 hours until constant weight is achieved.
vii. Weigh the dry biomass using a digital balance.
viii. Repeat the above steps at regular intervals (e.g., every 7 days).
Observation
Table:
|
Days After Planting |
Leaf Area (cm²) |
Dry Weight (g) |
LAI |
RGR |
NAR |
Remarks |
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Result:The calculated growth parameters reflect the physiological efficiency and growth performance of the selected fruit crop under current environmental conditions.
Assignments:
a) What is the significance of Leaf Area Index in crop studies?
b) How does RGR differ from NAR?
c) Why is dry weight used instead of fresh weight in growth analysis?
d) How can leaf area be measured without a leaf area meter?
e) What factors affect the value of LAI in a growing fruit crop?
