Yellow leaf

Subbaiah, C.C., P. Manikandan, and Y. Joshi. 1986. Yellow leaf spot of cashew a case of molybdenum deficiency. Plant Soil 94 35 42. 

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. 

Leaves with spots or blotches. Cause Various fungi. Brown, black, or yellow leaf spots may enlarge and kill entire leaves. Remove severely infected plants and plant parts. Avoid wetting leaves when watering. Apply sulfur sprays when symptoms appear to avoid further damage. 

Symptoms Infection by wilt fungi cause leaves to yellow and leaf stems to droop, giving plants a wilted appearance. The yellow leaf patches turn brown and may spread to cover whole leaves. Leaves often fall early, and plants will die. Symptoms usually first appear on the lower or outer parts of plants. The interior of the stem near the base may be discolored (see photograph of stem damage on page 396). 

Figure 2. Phytoplasma disease symptoms on some medicinal plants (1) Cannabis witche s -broom, (2) Achyranthes yellow leaf, (3) Hibiscus yellowing, (4) Catharanthus roseus plant showing phyllody symptom, (5) Catharanthus little leaf, (6) Discolouration in rose, (7) Flower virescence of lily, (8) Multiple meristem of lily, (9) Witches broom disease of lily, (10) Advanced yellowing and loss of the entire crown of coconut, (11) Lethal yellowing of coconut, (12) Portulaca little leaf, (13) Yellowing, crinkling and tip necrosis of papaya, (14) Reddening and plant stunting of Bupleurum falcatum, (15,16,17) Echinacea floral malformation, (18) Echinacea leaf yellowing.

Areca catechu (Arecaceae) Yellow leaf disease India Pumshothama et al. (2007)... 

Phoneix dactylifera (Arecaceae) Lethal yellowing Leaf stunting, yellow steaking, mask reduction in fruit and stalk size Alhudaib et al. (2008)... 

Ponnamma et al. (1991) identified a vector responsible for spread of yellow leaf disease of Are ca catechu from infected to healthy plant is Proutista moesta in India. 

Ponnamma, K.N., Rajeev, G. and Solomon, J.J. (1991). Detection of mycoplasma-like organisms in Proutista moesta (Westwood) a putative vector of yellow leaf disease of arecanut. Journal of Plants Crops, 19 63-65. 

Purushothama, C.R.A., Ramanayaka, J.G., Sanos, T., Casati, P. and Blanco, P.A. (2007). Are phytoplasmas the etiological agent of yellow leaf disease of Areca catechu in India Bulletin of Insectology, 60 161-162. 

Cyclic nitramine compounds such as RDX and HMX appear to have different modes of action in plants compared to the nitroaromatic compounds. Their basic structure and behavior in plants are similar to those of the triazine herbicides such as atrazine and simazine, which inhibit photosystem II in photosynthesis [32], The inhibition of photosynthesis may also be one of the modes of toxicity of cyclic nitramines based on symptoms such as chlorosis, necrosis, yellow leaf spots, and anthocyanin expression [27], However, the mechanism(s) of phytotoxicity of cyclic nitramines have not been investigated thoroughly. 

PHYSICAL PROPERTIES yellow, leaf-shaped crystals aromatic odor chloroform-like odor soluble in alcohol, benzene, chloroform, ether, petroleum ether, mineral acids, and oils, insoluble in water MP (114-117°C, 237-243°F) DN (lOSOkg/m ) SG (1.05) VP (3.3 x 10 mmHg at 25°C). 

Yellow Leaf Which Gradually Turned Brown. 

Fig. 30. N (Is) spectrum of (a) upper surface of yellow green leaf (b) lower surface of yellow green leaf (c) upper surface of yellow leaf and (d) lower surface of yellow leaf. Note the relative heights and half-widths and shifts of peaks which reflect the quantity of species and the changes in their chemistry. Primary peak positions are marked by arrows. Reprinted with permission from T. L. Barr, S. Seal, S. E. Hardcastle, M. A. Maclauran, L. M. Chen, and J. Klinowski, Bull. Pol. Acad. Sci. 45,1 (1997).

Mixt. of tautomers in soln. Probable struct. Isol. from the yellow leaf deposit of ferns Pitryogramma triangularis. Yellow prisms or plates (MeOH). Mp 137-140°. 

Export of ricinine from senescent leaf tissues has been unequivocally established (Table 6.4) in a time course study about the accumulation of ricinine and its demethylated forms in the stems and yellow and green leaves following the administration of [3,5- C]ricinine to a yellow leaf. In... 

Table 6.4. Demethylation and Translocation of [3,5- C]Ricinine from Yellow Leaf to Green Leaf of Castor Bean Plant Cuttings ...

Figure 6.15 shows the demethylation and translocation of [3,5-ricinine administered to a yellow leaf attached to the lower part of the stem of a mature castor bean plant. The radioactivity of ricinine and the... 

Figure 6.15. Demethylation and translocation of [3,5- K ]ricinine from the yellow leaf to the adjacent green leaf of the castor bean plant cutting with one green and one yellow leaf, a— Ricinine in yellow leaves b—demethylated ricinines in yellow leaves c—ricinine in stems d—demethylated ricinines in stems e—demethylated ricinines in green leaves /—ricinine in green leaves g— green leaf h—yellow leaf (Lee and Waller, 1972). Courtesy of Peigamon Press, Ltd., copyright 1972.

Interpretations of the above two results were complicated by the fact that the radioactivity ratio between ricinine and its demethylated forms did not necessarily indicate the ratio of translocated forms since the demethylated form of ricinine upon arrival to the green leaf from the yellow leaf may undergo methylation. The result showed that ricinine administered in the yellow leaves was translocated to healthy parts of the plant, especially the growing apex where ricinine is actively synthesized. The result supports the idea that a ricinine translocation process might be a salvage operation performed by the plant in order to reutilize ricinine from the leaves which are being prepared for abscission. This is a broad concept of... 

Crown rust usually seen in late summer. Pale yellow leaf flecking, followed by bright orange/yellow oval pustules. Brown rust is similar in appearance but is found in spring/ early summer. 

Fig. T. Coomassie blue stained 10-20% SDS polyacr> lamide gel showing the polypeptide compositions of PS I complexes from the four Nicotiana tabacum species a) Wild type tobacco JWB (10 pg chlorophyll) b) Mutant Su/su (10 pg chlorophyll) c) Mutant Su/su var. Aurea (10 pg chlorophyll) d) Mutant NC 95, yellow leaf patches (10 pg chlorophyll)...

Fig. 2 Immunological determination of phosphatidylglycerol (PG) by Western blot analysis of PS I polypeptides from the four Nicotiana tabacum species a) SDS-PAGE analysis of PS I polypeptides from JWB (10 jLig chlorophyll) b-e) Nitrocellulose membranes after the reaction with PG antiserum (8 P2/4, dilution. 1 200) with PS I polypeptides from b) Wild type tobacco. JWB (10 pg clilorophyll), c) Mutant Su/su (10 pg chlorophyll), d) Mutant Su/su var. Aurea (10 pg chlorophyll), e) Mutant N( " 95, yellow leaf patches (10 pg chlorophyll), f) Nitrocellulose membrane with PS I polypeptides from. JW B (10 pg chlorophyll) after the reaction with control antiserum (8 Pq, dilution 1 200)...

Carotinoids are fat-soluble hydrocarbon pigments widely distributed in low concentrations throughout the animal and plant kingdoms. They are orange or red in colour, crystallisable, freely soluble in light petroleum, chloroform and similar fat-solvents, but insoluble in water. They are easily bleached by oxidation, and give a deep blue colour in presence of concentrated sulphuric acid (the carotinoid reaction). Since they accumulate in oils and fats, they are also termed lipochromes. Carotinoids impart the typical colour to egg-yolk, the corpus luteum of the ovary, butter fat, liver oils, carrot, turnip, maize, tomato, the sere and yellow leaf, and many fruits and flowers. 

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