Leaf margin

Nifrogen dioxide Irregular, white or brown collapsed lesions on intercostal tissue and near leaf margin Middle-aged leaves most sensitive Mesophyll cells 2.5 4700 4 hr... 

Acid-t) pe necrotic lesion tip burn on fir needles leaf margin necrosis on broad leaves... 

Saline soils are often recognized in the field by the presence of a white surface crust, by damp oily-looking surfaces devoid of vegetation, stunted plant growth, and sometimes by tipbum and firing of leaf margins. Soil analysis rather than visual observations are nevertheless needed to properly assess salinity. 

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. 

Wilf P (1997) When are leaves good thermometers A new case for leaf margin analysis. Paleobiology 23 373-... 

Figure 4. Sketches of representative leaves showing various leaf characteristics, (a) illustrates a lobed leaf with an acute apex, a round base, and no teeth (like (b) and (c)). (b) illustrates an ovate shaped leaf with an attenuated apex (drip-tip), and a cordate base, (c) illustrates an obovate shaped leaf with a round and emarginate apex, and an acute base, (d) illustrates a leaf margin with teeth that are compound, acute, closely spaced, and regularly spaced, (see Wolfe (1995)) [Used by permission of Geological Society of America, from Forest et al. (1999), Geol. Soc. Am. Bull., Vol. Ill, Fig. 6, p. 505.]...

Symptoms observed in phytotoxicity tests of soil-applied atrazine and metribuzin were similar to simazine, except they appeared more rapidly after application, progressed more quickly into the interveins, and caused the leaf margins to become necrotic. Symptoms observed in terbutryn and prometryn phytotoxicity tests were chlorosis in the leaf veins, rather than interveins, which is more typical of injury from diuron or terbacil. 

On iris, gladiolus, tulip, and similar plants susceptible to fluoride injury, a narrow, dark-colored band often separates the dead and living tissue, and a series of these bands will develop as new tissue is killed by continued accumulations of fluorides. Similar bands may develop on leaves of susceptible woody species, but the necrotic tissues may also break away in a few days, leaving an irregular leaf margin. The leaf seldom separates from the tree because of the injury unless extremely high atmospheric concentrations of HF have occurred. 

Acute injury on parallel-veined leaves of monocotyledonous plants typically develops at the tip of the leaf blade. Repeated exposures to lethal dosages of fluoride will extend the necrotic lesion toward the base of the blade. Sometimes the lesions extend farther down the leaf margin than nearer the midvein, and often the lesion on one margin will extend farther down than on the opposite side. Living and dead tissue is usually separated by an abrupt line of dark-colored tissue. Successive fumigations often produce a series of these dark-colored bands. 

Currently no herbicides are cleared for use in the U.S. to control weeds in Jerusalem artichokes. Preliminary tests with several herbicides have been reported (Table 12.1). For example, the cultivar Columbia displayed satisfactory tolerance to preplant incorporated treatments of chloramben, S-ethyl dipropylthiocarbamate (EPTC), ethalfluralin, pendimethalin, and trifluralin, although metribuzin resulted in considerable damage, manifested as chlorosis and necrosis of leaf margins, and reduced plant height. Tuber yield, however, was not increased by weed control, whether via herbicides or hand weeding, when compared to weedy control treatments (Wall et al., 1987). 

Are there any changes in colour of leaves or needles Can there be seen signs of necrosis If so, are they irregularly distributed, which often is considered as typical for ozone injury, for example, in tobacco or pinto beans (Plate 7 and 8) Or are they concentrated on leaf margins and tips, which often is observed after the slow accumulation of chloride (Halbwachs, 1963) or fluoride (Guderian et al., 1969) Plate 9 shows typical marginal necrosis of an elm leaf, plate 10 tip necrosis of tulip leaves, whereas the flowers themselves are not injured. Acute injury by SO2 often appears as interveinal chlorosis followed by necrosis which can be seen at an elm leaf in plate 11. On the contrary, ozone injury mostly consists of small chlorotic or necrotic spots. Pine needles (plate 12) and... 

Plate 9. Marginal yellow leaf chlorosis and brown necrosis as a result of the accumulation of fluoride in leaf margins of elm tree (Ulmus pumila L.). Ogden, Utah. U.S.A., 1969. 

Cre nate.—Applied to leaf margins having rounded teeth. 

L ves with notched leaf margins. Cause Japanese weevils. The A", brown adults attack foliage, and the legless white grubs feed on roots. Apply a sticky substance, such as Tanglefoot, to the lower stems to prevent adults from climbing up the plants. Drench the soil around the base of the plant with a solution of parasitic nematodes to control the larvae. Spray leaves several times with pyrethrin for major infestations of adults. 

Seedlings cut off at ground level leaf margins ragged. Cause Cutworms. Young cut-... 

Temperatures below 35°F cause outer leaf margins to turn tan and leaves to blister. Protect plants with row cover if low temperatures are predicted. 

Vines wilt at midday leaf margins brown. 

Damage Mites burrow from undersides into leaf tissue of pears, currants, and many ornamentals. Leaves react by forming raised blisters, puckers, or galls along leaf margins. 

Necrotic leaf margins (toxicity of salts and some heavy metals)... 

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