Foliage leaves

Assimilation Parenchyma (Chlorophyll or Chromophyll Parenchyma, Chlorenchyma).—This form of parenchyma tissue is found in foliage leaves, floral leaves, in the outer region of young green stems and fruits. Its cells are thin walled and vary in shape from more or less isodiametric to irregular and elongated forms. The cells always contain chloroplasts or plastids, in whose pores may be found some other coloring substance. 

Scale Leaves.—Scale leaves are reduced foliage leaves. They are found on certain rhizomes, above ground stems, such as Dodder, etc., on bulbs, and forming the protective scales of scaly buds. 

Foliage Leaves.—These are the common green leaves so familiar to all. 

Fig. 160.—Cycas revoluta, showing terminal bud of foliage-leaves just opening.

Heterophyllous.—Having more than one kind of foliage-leaves on the same plant. 

Leaves stippled with white. Cause Oak lace bugs. Adult lace bugs are Vio", flattened, dark insects with lacy-pattemed, silvery white wings. Both the adults and the tiny nymphs feed on the undersides of leaves, sucking the sap and producing a gray, splotched or stippled appearance to the upper sides of the foliage. Leaves may curl, turn brown, and drop... 

Leaves show considerable variation in size, shape, arrangement of veins, type of attachment to the stem, and texture. They may be simple or divided into leaflets, i,e, compound (see illustration), Types of leaf include cotyledons (seed leaves) scale leaves, which lack chlorophyll and develop on rhizomes or protect the inner leaves of a bud foliage leaves, which are the main organs for photosynthesis and transpiration and bracts and floral leaves, such as sepals, petals, stamens, and carpels, which are specialized for reproduction. 

A flourish of foliage Leaf size, color, shape, and texture are important considerations when designing ornamental effects with vegetables, as many are not allowed to flower. Here, a ribbon of bold pumpkin leaves runs through flowering plants. 

CLADODE A branch assuming the form of, and closely resembling, an ordinary foliage leaf. 

Foliage of Douglas fir had only trace amounts of (+)-camphene in trees from the coast but major concentrations in trees from the other three sites, hi contrast, ter-pene mixtures from lodgepole pine leaf and bole tissues had nearly the same levels of the major compound, (-)-P-phellandrene, and minor components regardless of origin. Patterns of variation in the other species were less extreme. 

The regulations require three samples from the treated plot (one from each subplot) and a single sample from the control plot at each sampling interval. For foliage the preferred technique is to collect leaf punch samples. Leaf punch samplers are available in 5-, 2.5- and 1.25-cm punch areas. Common practice requires a sample of 40-5-cm leaf disks to provide a 400-cm sample using both the top and bottom of the leaf disk to calculate sample surface area. 

Popendorf et al. (1975) suggested a relationship between respiratory exposure and organic foliar dust released from the foliage due to crop disturbance therefore, it was hypothesized that crop density may be associated with both dermal and respiratory exposure. However, in the present study, no such relationship could be observed. This may be due to the large variation in the method used to determine crop volumes. Improvement of the crop-volume/leaf-surface-area method may contribute to the clarification of whether crop density can be considered a determinant of re-entry exposure. 

Atrazine enters plants primarily by way of the roots and secondarily by way of the foliage, passively translocated in the xylem with the transpiration stream, and accumulates in the apical meristems and leaves (Hull 1967 Forney 1980 Reed 1982 Wolf and Jackson 1982). The main phytotoxic effect is the inhibition of photosynthesis by blocking the electron transport during Hill reaction of photosystem II. This blockage leads to inhibitory effects on the synthesis of carbohydrate, a reduction in the carbon pool, and a buildup of carbon dioxide within the leaf, which subsequently causes closure of the stomates, thus inhibiting transpiration (Stevenson et al. 1982 Jachetta et al. 1986 Shabana 1987). 

Foliage of cotton that initially contained 100 mg/kg DW contained about 60 mg/kg after 7 weeks leaf residues consisted entirely of the parent diflubenzuron (Gartrell 1981). Diflubenzuron applied topically to lima bean (Phaseolus lunatus) foliage was not absorbed by the plant, as expected. Injected diflubenzuron, however, was metabolized, and certain metabolites were similar to those isolated from mites (Franklin and Knowles 1981). 

The limiting factor in tomato production in the tropics is more apt to be a virus disease than a fungus disease of the foliage. The control of virus disease by control of the insect vector has been investigated in Mexico on potatoes (leaf roll, purple top), tomatoes (several unidentified viruses, one of which perhaps is curly top), and corn (corn stunt). Virus control in this way has been variable but usually negligible. This lack of control perhaps is due to slow kill of the insect vector, or to the continuous entry of the vector into the field. 

Foliage Deterioration, Chronic Leaf Drop, Dieback... 

Foliage deterioration, chronic leaf drop, and dieback are caused by numerous fungi, acting in semiparasitic fashion Gloeosporium cingulatum S. and V.S. = Cal-letotrichum coffeanum Noack, Phoma sp., and others. 

Caterpillars and grasshoppers cause localized damage to banana foliage. Bordeaux coverage of the banana leaf surfaces, however, acts as a partial repellent to these insects. 

Peach leaf curl disease infects leaves as they unfold in spring, causing red blistering and distortion of the foliage. A temporary shelter to keep rain off until all the leaves have appeared should reduce infection. 

In fall and winter, canker bacteria, spread by rain-splash from the leaves, enter twigs through leaf scars to cause canker lesions. In spring and summer the foliage is attacked, but no new cankers are formed. 

Symptoms Browning of foliage on the side of a plant facing the prevailing wind. Individual leaf margins or tips may be markedly browner than the leaf centers. Apples and other fruit may show a red/ brown russeting on the skin surface. 

Spinosad (Fig. 9) is a mixture of spinosyn A and spinosyn D, originally isolated from the soil Actinomycete, Saccharopolyspora spinosa. Spinosad is recommended for the control of a very wide range of caterpillars, leaf miners, thrips and foliage-feeding beetles. Spinosad is sold as an aqueous based suspension concentrate formulation under several trade names. 

Benzyl isothiocyanate was identified in aqueous extracts of C. sativa foliage by Lovett and Duffield ( ). Tang, Bhothipaksa and Frank ( ) showed that E. cloacae was capable of degrading benzyl isothiocyanate to hydrogen sulfide and benzylamine. Tests were, accordingly, carried out with incubated leaf washings of Camelina and showed the presence of hydrogen sulfide and... 

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