Leaf sections

Lamoureux, G.L., Shitnabukuro, R.H., Swanson, H.R., and Frear, D.S. Metabolism of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) in excised sorghum leaf sections, / Agric. Food Chem., 18(l) 81-86, 1970. 

Microautoradiographs of the harley leaf immediately after spraying showed the radioactive substance on the epidermis (Figure 6). However, a sequential time series of microautoradiographs of cryostat leaf sections (8 ym) shows that triadimefon and/or its metabolites are rapidly taken up (Figure 7). Subsequent transport takes place almost exclusively with the transpiration flow in the xylem. This transport system is then rapidly abandoned again so the active substance and/or metabolites move out of the transportation stream and are found in all leaf cells (29). 

We will perform one of the two bioassays dealing with tannins in insect diet The compounds to be tested (tannic acid) are mixed into diet in varying concentrations. We measure how much chow the caterpillar has consumed and whether the effect is concentration dependent. (The second bioassay - in Chap. 19 - employs the Leaf disk lest. In this often used bioassay leaf sections of a standard size are treated with the compounds in question.)... 

We will perform the Leaf disk test, also known as leaf disk assay or leaf disk choice test, the second of two bioassays of tannins in the diet of insects in this book. In this often used bioassay, leaf sections of a standard size are treated with the compound(s) in question. Several circular leaf sections ( leaf disks ) (Ali et al. 1999, Filho and Mazzafera 2000, Shields et al. 2008, Wheeler and Isman 2000) or cellulose membrane filters (Hollister and Mullin 1999, Larocque et al. 1999) are presented to a caterpillar in a choice experiment. We measure how much chow the caterpillar has consumed and whether any feeding inhibition is concentration dependent. Regardless of what compounds are being tested, leaf disk tests serve as an important tool in bioassaying feeding inhibitors and stimulants in insects. The cited references are examples of such studies. (In the first tannic acid experiment - Chap. 18 - the tannic acid was mixed into diet in varying concentrations.)... 

Figure 11. The chlorophyll content of leaf sections of two biotypes of Conyza treated for 24 or 48 h with paraquat at 10 M, at various light intensities (41).

The accumulation of nitrite in leaves under dark anaerobic conditirms provided the rationale for the development of a convenient in vivo assay for nitrate reductase. In the assay, leaf sections are suspended in buffer (pH 7.5) with or without nitrate and various other metabolites (e.g., glyceraldehyde-3-P or malate) that can be oxidized to generate NADH and the system made anaerobic by vacuum infiltration or purging with Nj. After varying periods of dark incubation, accumulated nitrite is measured and related to in vitro nitrate reduction or actual accumulation of reduced nitrogen (Brunetti and Hageman, 1976 Ferrari and Varner, 1970 Jones and... 

Stafford, H.A. (1960). Differences between lignin-like polymers formed by peroxidation of eugenol and ferullc acid In leaf sections of Phlem. Plant Physiol., 35, 108-114. 

Gas Exchange. CO2 assimilation and transpiration were measured using an open, flow-through apparatus and infrared gas analysis. Distilled H2O was continuously provided to the entire cut edge of the leaf disc enclosed in a Leaf Section Chamber (Analytical Development Co., Hoddesdon, U.K.). The vapor pressure deficit was maintained at 8.9 1.0 or 18.4 1.0 mbars. This corresponds to relative humidity levels of 72% and 42%, respectively. 

TABLE 2. Total light activity, activation, and dark inhibition of ru-bisco in extracts of leaf sections from different regions (base to tip) along the blade, for the rice cultivar Lemont, 26 days after planting. 

Distance of Leaf Section from Base Total Rubisco Activity Rubisco Activation Rubisco Dark Inhibition... 

The fifth well developed leaf from field grown maize (Zea mays L. cv. Dea ) was used in the experiments. In the middle of the leaf blade, 20 cm from the tip, leaf disks (0 6cm) were cut under water. They were dried with filter paper and mounted like a diaphragm into a thermostated leaf section chamber (HARRIS et al. 1983, LONG et al. 

The chloroplast (o) and cytosolic ( ) PGK in 1cm leaf sections of 8 day-old light grown barley seedlings. 

Carbon dioxide uptake (A) and transpiration were measured after fumigation in a separate leaf section chcunber (LSC, ADC Ltd. UK) using the gas analysis system described previously (3). The CO2 concentration was varied with a gas blender (series 850, Signal Ltd. UK) using cylinders of N2/ O2 and C02-... 

Fig 1. Comparison of Chlorophyll fluorescence induction kinetics curves of 6 wheat Cultivars (W-1...W-6) in the order of decreasing frost resistance. Each curve was plotted after accumulation and average from 10 measurements. 3 leaf sections for one measurement. 

NM-1 Ximeng, Inner Mongolia, China Leaf sections 60 0 ... 

A to E refer to successive sections up the leaf. Section A is, therefore, at the base of the leaf and contains the youngest tissue. 

Leaf section Galactolipid (mg/g dry weight) Phospholipid (mg/g dry weight) ... 

After 3 and 7 days, remove small leaf sections and place in a drop of water between a slide and coverslip (Fig. 3). Examine samples under UV light in the epifluorescence Zeiss Axioplan 2 HBIOO microscope with additional DIG filter (differential contrast) that can visualize GFP (excites at 488 nm) and RFP (excites at 543 nm). Capture the images with a Zeiss camera with AxioCam MRC5 using AxioVision software. 

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