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## Parameters arrived through growth analysis

- It is the surface area of leaf, which aids in photosynthesis.
- Total leaf area per plant is often a useful measurement in bio-productivity studies.
- Area can be measured by graphic methods, weight method, by using Leaf Area Meter and by measuring length and breadth of the leaf.
- Watson (1947) proposed the term leaf area index which is the ratio of the leaf area of a plant to the ground area occupied by the plant.
- The term leaf area ratio was suggested by Redford (1967).
- It is defined as the ratio of area of the leaf to the total plant biomass per plant.
- It is expressed in terms of cm
^{2}g^{-1}. - It is ability of the plant to maintain the green leaves per unit area of the land over a period of time.
- It reflects the vitality of leaves and an opportunity for assimilation.
- It also measures the persistence of the assimilating surface.
- This factor was suggested by Power et al.(1967) and expressed in days.
- In order to estimate the carbon assimilatory efficiency of leaves or to estimate the leafiness of plants, Radfort (1967) suggested leaf area ratio as a measure of leaf area to the weight of the whole plant. It is expressed as cm
^{2}g^{-1}. - In broad sense, LAR represents the ratio of photosynthesizing to respiratory material within the plant.
- It is the ratio of assimilating area to its dry weight.
- Following formula was proposed by Kvet et al. (1971) to arrive SLA and expressed as cm
^{2}g^{-1}. - Using the leaf dry weight and leaf area, SLW is calculated.
- It is the ratio of leaf dry weight to its area of assimilating surface.
- The formula was suggested by Pearce et al. (1968) and expressed as mg cm
^{-2}. - It is the ratio of total leaf dry weight to the whole plant dry weight.
- It is the measure of leafiness of the plant on a weight basis.
- It is expressed in g kg
^{-1}. - It is the rate of increase of leaf by dry weight per unit area of leaf per unit time.
- Williams (1946) employed the formula and expressed as mg cm
^{-2}day^{-1} - It is the rate of increase of dry weight per unit weight already present per unit time.
- Williams (1946) suggested the formula.
- CGR is a simple and important aid of agriculture productivity.
- It is the rate of increase of dry weight per unit land area per unit time.
- Watson (1958) suggested the following formula to arrive Crop Growth Rate
- It reflects the proportion of assimilate distribution between economic yield and total biomass yield (Donald and Hamblin, 1976).
1) Leaf Area (LA) X
LA = ---------- x B
A Where X = known area of leaves The leaf area of standard leaves, usually 3rd leaf from the top is measured and dried.A = dry weight of known area of leaf B = dry weight of unknown area of all leaves B) Linear measurement method LA = LBK (cm Where ^{2} or m^{2})L=maximum length, B=maximum breadth, K=constant (can be worked out by regression analysis)
K value may not be the same for different varieties in the same species. 2) Leaf Area Index (LAI)
Total leaf area of the plant
Leaf area index = -----------------------------------------------------
Ground area occupied by the plant (spacing) 3) Leaf Area Ratio (LAR) Leaf area per plant LAR = ----------------------------- Total plant dry weight 4) Leaf Area Duration (LAD) L1 + L2 LAD = ----------------- x (t2 – t1) 2 Where LAI (i) – Leaf area index at first stage LAI (ii) - Leaf area index at second stage t2 –t1 – Time interval between the two consequent stages and expressed in days. 5) Leaf Area Ratio (LAR) L1 + L2 LAD = ----------------- x (t2 – t1) 2
Leaf area SLA = -------------------------- Leaf dry weight 7) Specific Leaf Weight (SLW) Leaf weight SLW = ----------------- Leaf area 8) Leaf Weight Ratio (LWR) Leaf dry weight LWR = ---------------------------------------- Total plant dry weight 9) Net Assimilation Rate (NAR) ^{}Where Log e L2 = Natural log of leaf area at stage 2. Log e L1 = Natural log of leaf area at stage 1. L2 & L1 = Leaf area at stage 2 & 1 respectively W2 & W1 = Dry weight of the whole plant at stage 2 & 1 respectively t2-t1 = Time interval between the two stages NAR is expressed as mg cm ^{-2} day ^{-1}10) Relative Growth Rate (RGR) Loge W2 – loge W1 RGR = ----------------------- t2 – t1 W2 & W1 = Whole plant dry weight at t2 & t1 respectively and expressed as g g 11) Crop Growth Rate (CGR)^{-1} day^{-1 }Where, W2 and W1 are total plant dry weight at time t2 and t1 and P is plant population per unit area. CGR is also the product of leaf area index and net assimilation rate. CGR = LAI X NAR CGR increases as LAI increases to an optimum because of greater light interception. CGR is expressed as mg m ^{-2} day ^{-1}.12) Harvest Index (HI) |

Last modified: Wednesday, 13 June 2012, 6:34 AM