Natural isothiocyanates, produced during plant tissue damage from methionine-derived glucosinolates, are potent inducers of mammalian phase 2 detoxification enzymes such as quinone reductase (QR). A greatly simplified bioassay for glucosinolates based on induction and colorimetric detection of QR activity in murine hepatoma cells is described. It is demonstrated that excised leaf disks of Arabi...

Two types of segments (intact leaf tissue and isolated mesophyll tissue respectively) were isolated from basal (still growing) and tip (non-growing) maize leaf regions. The leaf segments were exposed to different light qualities (blue or red light) and quantities, and net fluxes of K+, Ca2+ and H+ were measured non-invasively using ion-selective vibrating microelectrodes (the MIFE technique). A...

The effect of free radicals on the cell metabolism is well established. Plants are rich natural sources of antioxidants, which are most effective agents to prevent free radical associated adverse cellular interactions. The purpose of this investigation was to find out the free radical scavenging efficacy associated with Colocasia esculenta whole leaf juice. The free radicals were generated usin...

Dark green islands (DGIs) are a common symptom of plants systemically infected with the mosaic virus. DGIs are clusters of green leaf cells that are free of virus but surrounded by yellow leaf tissue that is full of virus particles. In Cucumber mosaic virus (CMV)-infected Nicotiana tabacum leaves, the respiration and photosynthesis capabilities of DGIs and yellow leaf tissues were measured. The...

BACKGROUND Modification of leaf traits in sugar beet requires a strong leaf specific promoter. With such a promoter, expression in taproots can be avoided which may otherwise take away available energy resources for sugar accumulation. RESULTS Suppression Subtractive Hybridization (SSH) was utilized to generate an enriched and equalized cDNA library for leaf expressed genes from sugar beet. F...

A wound signal originates at the site of injury in lettuce (Lactuca sativa L.) leaf tissue and propagates into adjacent tissue where it induces a number of physiological responses which include increased phenolic metabolism with the de novo synthesis of phenylalanine ammonia lyase (PAL, EC 4.3.1.5), the synthesis and accumulation of soluble phenolic compounds (e.g., chlorogenic acid), and subse...

Specimens of the broad-leaved conifer, Liaoningocladus boii Sun, Zheng & Mei 2000 were evaluated from the mid Early Cretaceous Yixian Formation occurring overwhelmingly at Dawangzhangzi, Liaoning Province, NE China. Arthropod-mediated plant damage types (DTs) were categorized for 343 specimens of this host; one of these DTs represented a distinctive leaf-mine, DT280, established as Fossafolia o...

Human-induced increases in atmospheric CO2 concentration have the potential to alter the chemical composition of plant tissue, and thereby affect the amount of tissue consumed by herbivorous arthropods. At the Duke Forest free-air concentration enrichment (FACE) facility in North Carolina (FACTS−1 research facility), we measured the amount of leaf tissue damaged by insects and other herbivorous...

Using a manometric method, photosynthetic oxygen evolution and (14)CO(2) fixation have been determined for leaf tissue of Triticum aestivum L., Hordeum vulgare L., Phaseolus vulgaris L., and Lemna minor L. Approximately similar values in the range 0.2 to 0.4 millimoles grams fresh weight(-1) hour(-1) were obtained for both gases. In tissue subjected to vacuum infiltration, O(2) evolution and (1...

The prolific amount of growth and reproduction in invasive plants may be achieved by greater net photosynthesis and/or resource-use efficiency. I tested the hypotheses that leaf-level photosynthetic capacity and resource-use efficiency were greater in two invasive species of Rubus as compared with two noninvasive species that have overlapping distributions in the Pacific Northwest. The invasive...