Trichomes density

In times of less accessibility of water, the plants seem to increase the cannabinoid content. It is suggested that the plant will cover itself with the oily cannabinoids to prevent water evaporation. For instance Sharma (1975) found increased glandular trichome densities in the leaves of Cannabis grown under dry circumstances [55]. 

Plant Trichome Length Number of Cells/Trichome Density (number/mm2)... 

Several woody plant species will react to exposure of simulated acid rain by forming foliar lesions. While the pH level of simulated acid rain that produced these lesions varies from species to species, the lesions themselves are generally yellow to brown necrotic spots or regions (see Table 1). Additionally, on two clones of poplar, galls were formed in response to simulated acid rain. Surface characteristics such as stomatal presence and density, trichome density, type and amount of epicuticular wax, leaf surface wettability and buffering capacity have all been shown to influence foliar injury by simulated acid rain. However, it may be... 

The inheritance of glandular trichomes in S, berthaultii and in crosses with 5. tuberosum has been studied by several groups (11. 35-371. Type B trichome density, droplet size and presumably the presence of sucrose esters appear to be controlled by relatively few recessive genes. Heritability estimates ranged from 20-30% for density of Type A and B trichomes and 60% for Type B droplet size. The presence of polyphenoloxidase in type A trichomes is controlled by a single dominant gene (381. The inheritance of sesquiterpenes in type A trichomes has not been studied. 

We have cloned the 59 kD trichome PPO from a cDNA library constructed from epidermal mRNA (H. Yu and J. Steffens, unpublished data) and are currently using this clone as a probe to isolate the genomic DNA encoding the S. berthaultii trichome PPO (S. Newman and J. Steffens, unpublished data). These studies may allow us to increase the insect entrapping abilities of cultivated potato, which has retained low Type A trichome densities and no longer possesses the biochemical machinery... 

O. 16). However, because 2-tridecanone is contained within the glandular trichome tips of the more resistant lines, it was not possible to separate the effects of 2-tridecanone from those of the trichome density alone (63). High densities of foliar trichomes have been shown to adversely affect Trichogramma spp. in other plant species (28), and it is clear that they have an effect in this system. This is shown by the reduction of parasitization on the Fi line, which has a much higher trichome density than esculentum, but no 2-tridecanone. 

Plant line Mean Trichome Density no. /mml Mean 2-tridecanone ng/mm Mean Percent Parasitism July 29 Aug 8 Aug 13 ... 

In field cage studies in which zea larvae on several plant lines were exposed to adult parasitoids (one plant line per cage), percent paras itization by both species was significantly lower on BC2, (a backcross ((L, esculentum x PI 134417) x PI 134417) line with intermediate levels of 2-tridecanone and glandular trichome density), and PI 134417 than on L. esculentum and the Fi hybrid (L. esculentum X PI 134417) (Table ViTT. This pattern reflects levels of 2-tridecanone-mediated resistance to sexta. These data indicate that fewer zea larvae are parasitized on the more resistant plant lines but do not indicate whether this is due to elevated densities of glandular trichomes or methyl ketones, or both. 

Kauffman, W. C. and G. G. Kennedy. 1989a. Relationship between trichome density in tomato and parasitism of Heliothis spp, (Lepidoptera Noctuidae) eggs by Trichogramma spp, (Hymenoptera Trichogrammatidae). Environ. Entomol. 18 698-704. 

Boughton AJ, Hoover K, Felton GW. (2005) Methyl jasmonate apphcation indnces increased densities of glandular trichomes on tomato, Lycopersicon esculentum. J Chem Ecol 31 2211-2216. 

In medieval times, cities commonly erected walls as a protective barrier to invasion. Plants have evolved similar protective mechanisms. Thorns and nettles which repel most herbivores are two examples of protective barriers. To ward off Insect attack, plants have evolved non-glandular trichomes which act in a similar fashion. Thus, in some plants, the density, length, or branching of trichomes have been negatively correlated with insect survival (10). 

The wild tomato, Lycopersicon hirsutum f, glabratum is covered with trichomes which contain 2-tridecanone. The level of this compound is much lower in the domesticated tomato, U esculentum. This exudate proved to be toxic to Manduca sexta (tobacco hornworm) and to Heliothis zea (121). The density of glandular trichomes, which secrete 2-tridecanone, was influenced... 

Handelman et al. (1999) treated milled oat groat pearlings, trichomes, flour, and bran with methanol and tested the fractions for antioxidant capacity against low-density lipoprotein (LDL) oxidation and R-phycoerythrin protein oxidation in the oxygen radical absorbance capacity... 

The Jerusalem artichoke and other members of the sunflower family display a profusion of trichomes that often give the plant a very abrasive surface texture (Seiler, 1981). Trichomes are thought to function in part as a component of the herbivore defense system of the plant. In sunflower, introgression of biotic resistance traits is thought to have been important in adaptation (Whitney et al., 2006). The Jerusalem artichoke has at least four types of trichomes that differ in location, size, and density (Figure 4.5). 

Therefore, it may be possible to increase the resistance of cultivated sunflower to Hj. electellum by breeding for increased concentrations of sesquiterpene lactone-containing glandular trichomes on the anther tips. The development of new cultivated lines with high densities of glandular trichomes may prove to be an... 

In a micro-autography study, field collected Rhizosolenia-Richelia symbioses were incubated with C-labeUed bi-carbonate. Higher density of silver grains localized on the symbiotic Richelia trichomes than on the host Rhizosolenia filaments, suggesting that the Richelia were actively photosynthesizing and the host diatom were inactive (Weare et al., 1974). An equally plausible explanation for less silver grains on the Rhizosolenia host is that some of the fixed and labeled photosynthetic products were transferred to the host from the symbiont. Similar scenarios of carbon, and nitrogen transfer, are well documented in terrestrial... 

R549 H. W. Spiess, Multidimensional Solid State NMR Studies of Complex Dynamics in Polymers , AIP Conf. Proc., 2000, 519, 33 R550 O. Spring, Chemotaxonomy Based on Metabolites from Glandular Trichomes , Adv. Bot. Res., 2000, 31, 153 R551 M. Springborg, Density-Functional Theory , Chem. Model ., 2000, 1, 306... 

Adheslve entrapment. Mortality and immobilization of aphids increases with a rise in density of Type A and Type B trichomes and with increased volume of Type A trichome glands. Insects landing on the foliage first encounter Type B trichome exudate which forms an adhesive coating on the tarsi. This accelerates... 

Density of trichomes and stomata -- Densities of trichomes and stomata were determined from positive leaf impressions by the silicone rubber technique of Sampson (1961). A total of eight areas were sampled randomly on each of four leaf replicas. 

Although glandular trichomes can interfere with predators and parasitoids of aphids and the Colorado potato beetle, the inhibitory effect is largely associated with entrapment by type B exudate and is minimized on plants bearing moderate densities of these trichomes (42.43). 

During the 1970 s the USDA Nicotiana tabacum germplasm collection was evaluated in field plots at the Clemson University Pee Dee Research and Education Center, Rorence, SC for their resistance to the tobacco hornworm, Manduca sexta (L,) (1), and the tobacco budworm, Heliothis virescens (F.) (2). During this investigation a large variation in leaf trichome types and density was observed. Johnson et al. (3,4) classified the major trichome types from the various tobacco types as simple trichomes without exudates, glandular trichomes without exudates, glandular trichomes with exudates, and... 

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