The objective of this study was to develop a rapid non-destructive technique to estimate total chlorophyll (Chl) content in a maize canopy using Chl content in a single leaf. The approach was (1) to calibrate and validate a reflectance-based non-destructive technique to estimate leaf Chl in maize; (2) to quantify the relative contribution of each leaf Chl to the total Chl in the canopy; and (3)...

Effects of de®ciencies in N, P, K, Ca, Mg, B and Fe on leaf development, visual symptoms and shoot±root dry weight ratio were studied in Spathiphyllum `Sensation' grown hydroponically. Leaf nutrient contents of treated plants were analyzed to con®rm suspected de®ciencies. Leaf number, leaf area and chlorophyll content were all signi®cantly reduced in the nitrogen-de®cient plants similar to plan...

Resistance of four brassica leafy vegetables: kale, Chinese cabbage, rape and Ethiopian mustard to cabbage aphid, Brevicoryne brassicae (L.) was studied in cage experiments at the Botswana College of Agriculture, Gaborone, Botswana. A completely randomised design with cultivars as treatments and four replicates per treatment was used. One newly laid nymph was placed on each of the four potted p...

The chlorophyll fluorescence imaging technique is a valuable tool to study the impact of heavy metal stress in plants. The aim of this paper was to investigate the influence of Cd on photosynthetic apparatus of white cabbage (Brassica oleracea subsp. capitata f. alba) plants. Two cabbage cultivars ‘Ditmarska Najwcześniejsza’ (‘DN’; early) and ‘Amager Polana’ (‘AP’; late) were used. Cd was appli...

Spring wheat (Triticum aestivum L., cv. ‘Minaret’) was grown in open-top chambers and exposed to two CO2 concentrations (ambient and 680 ppmv) and two O3 concentrations (ambient and ambient +50 or +90 ppbv) either from anthesis onwards or for the entire growing season. The aim of the experiment was to test whether elevated CO2 could provide ‘protection’ to the crop against the damaging effects ...

  In a three-year (2004-2006), field experiment, we aimed to study changes in leaf physiological traits (leaf water potential-Ψleaf, leaf water content-LWC, carbon isotope discrimination-Δ, specific leaf area-SLA, chlorophyll content as assessed by SPAD and modified SPAD-MSPAD) and elemental composition (K, Na, Ca, Mg, K/Na, Ca/Mg, total leaf salinity-TLS) of sugar beets (cv. Rizor) grown unde...

ABSTRACT- The evaluation of leaf area and leaf nutritional value is important for crop growth modeling and estimations of its performance. The purpose of this study was to use image processing techniques to develop an economical method to ease the assessment of nutrient status and leaf area (LA) of plants and to compare the outcomes of this method with linear models. Leaf area and leaf chloroph...

The autumnal coloration of foliage in deciduous trees represents a most spectacular phytogerontological phenomenon. It is primarily due to the progressive loss of chlorophyll coinciding with the partial retention of carotenoids. Leaf senescence is a developmental process that is aimed at the recycling of nutrients to perennial parts of the tree for reuse upon the production of new foliage in sp...

Chlorophyll fluorescence has been routinely used for many years to monitor the photosynthetic performance of plants non-invasively. The relationships between chlorophyll fluorescence parameters and leaf photosynthetic performance are reviewed in the context of applications of fluorescence measurements to screening programmes which seek to identify improved plant performance. The potential role ...