What is the net assimilation rate?

a measurement of plant growth (weight increase per unit time) by assessing change in a particular part of the plant (usually leaf area) rather than in the overall plant.

How is net assimilation rate calculated?

Net assimilation rate (g m−2 day−1) Plant height (m)

What does assimilation rate mean?

A USEFUL measure of the photosynthetic efficiency of plants is ‘net assimilation rate’ (E) defined by Gregory1 as the rate of increase of dry weight (W) per unit of leaf area (L); that is: In measuring W the plant is destroyed, so changes in W can be determined only by successive sampling from a population of plants.

What is CGR in agriculture?

Leaf area duration (LAD) 6. Leaf area ratio (LAR) 1. Crop growth rate (CGR):- Crop growth rate (CGR) is the gain in dry matter production on a unit of land in a unit of tune.

How do you calculate assimilation?

3.3 Assimilation The assimilated portion of food ingested is that which is absorbed through the gut wall and taken up into the animal’s tissues, with the rest of the food egested as feces. The assimilation efficiency (AE) = (I−E)/I × 100%, where I is the ingestion rate and E is the egestion (defecation) rate.

How is Lai calculated?

Leaf Area Index (LAI), which is used as a measure in hundreds of studies on forests, crops, climate and the environment, is calculated as half the area of all leaves per unit area of ground. It is measured as the leaf area (m2 ) per ground area (m–2) and is unit-less.

How is carbon assimilation measured?

‘ The assimilation could also be measured by estimating the increase of carbon content of the leaf, but what is more usually done is to measure the increase of dry weight of the leaf and assume that this is proportional to the increase in carbon content.

What is carbon dioxide assimilation rate?

Net CO2 assimilation rate (A) remained similar at 6.54 ± 0.32 μmol m−2 s−1 but, stomatal conductance (gs) decreased significantly from 94.0 to 69.2 mmol m−2 s−1 under high water deficit treatment.

How is RGR calculated?

The RGR can be stated in terms of differential calculus as RGR=(1/W) (dW/dt) so that RGR is increasing in dry mass (dW) per increase in time (dt) divided by existing biomass (W).

What is the difference between RGR and AGR?

AGR is the simplest index to measure plant growth rate. Relative Growth Rate (RGR) takes into account the original difference in size of plants, which may have a significant influence on the increase in dry mass, and also the different performances due to the ageing of plants.

What determines assimilation efficiency?

Assimilation efficiency is the percentage of food energy taken into the guts of consumers in a trophic compartment (In) that is assimilated across the gut wall (A„) and becomes available for incorporation into growth or to do work. The remainder is lost as feces and enters the base of the decomposer system.

Where the assimilation efficiency is highest?

Herbivores assimilate between 15 and 80 percent of the plant material they ingest, depending on their physiology and the part of the plant that they eat. For example, herbivores that eat seeds and young vegetation high in energy have the highest assimilation efficiencies,…

What do you mean by net assimilation rate?

R. Hunt, in Encyclopedia of Applied Plant Sciences (Second Edition), 2017 This is an index of the productive efficiency of plants calculated in relation to total leaf area. It is synonymous with the term net assimilation rate. The usual symbol is E: the rate of dry weight production expressed per unit of total leaf area, LA.

How is assimilation rate different from unit leaf rate?

The term net assimilation rate is often used interchangeably with unit leaf rate but the latter is preferred4. They measure the net gain in dry weight of the plant per unit leaf area (kg m −2) and differ from photosynthetic rate which measures the net gain of carbon only during the light period.

What causes a decrease in the assimilation rate?

This reduction of photosynthetic activity is often correlated with a decrease in the RuBisCO activation level under moderately elevated temperatures, caused by RCA inactivation [29]. This is attributed to the thermolability of RCA, which is inhibited by moderately high temperatures in most plant species.

What is the net assimilation rate of groundnut?

Rao (1999) in his study reported that both HTs (40 vs. 35 °C) and CO 2 (660 vs. 330 ppm) significantly increased the net assimilation rate (NAR) of groundnut. At 330 ppm CO 2, NAR increased from 4.092 to 4.328 g m − 2 day − 1 with the increase in temperature from 35 to 40 °C.