Reddening of Cotton (Gossypium Hirsutum L.) Leaves

Reddening of leaves is a physiological disorder in cotton induced by different abiotic stresses. Dramatic biochemical changes occurred in reddening leaves: strong accumulation of anthocyanins and drop of chlorophyll content, important increase of proline content and peroxidase activity. The lipid peroxide content indicative of membrane fragmentation was decreased. In this way a multicomponent system encompassing anthocyanins, proline, and peroxidase may act coordinately to overcome abiotic stress in cotton.     

Zinc-deficient sprouting blight potatoes and their possible relation with neural tube defects

Maternal nutritional zinc deficiency is blamed in the pathogenesis of neural tube defects. In animal and plant domains zinc is required for growth and development. The objective of the present study was to show that sprouting blighted potato tuber is zinc deficient. In five potato varieties, zinc was measured by atomic absorption spectrophotometry in wet-ashed paired slices of edible potato tuber and in its peel, in blighted potato tuber and in its sprout. Zinc contents were measured as the mean (+/- SEM) and the following values were found, 0.388 +/- 0.036, 0.623 +/- 0.059, 0.550 +/- 0.030 and 1.089 +/- 0.181 mg per 100 g wet weight, respectively. In conclusion, we believe that long-term consumption of zinc-depleted, blight potato tuber by pregnant woman could be potentially teratogenic with the consequent birth of a baby with neural tube defects.     

Effects of Reddening of Cotton (Gossypium hirsutum L.) Leaves on Functional Activity of Photosynthetic Apparatus

Strong inhibition of rates of CO₂ assimilation and transpiration, stomatal conductance, and water use efficiency as well as photosystem 2 (PS2) photochemical activity were related to the severity of reddening. The inhibition of photosynthesis in red cotton leaves was due to both decreased photochemical activity and stomatal limitation. Lowered photosynthetic capacity could be one of the main factors of reduced yield in reddening cotton.     

Ursachen der Chlorosen an Mandarinen (Citrus Reticulata Blanco) der Ägäischen region

Zusammenfassung Im Gebiet von Gümüssu der Provinz Izmir (Türkei) wurden aus 20 repr?sentativen Mandarinenplantagen Blatt- und Bodenproben entnommen und auf Mikroelementgehalte untersucht. In den Bodenproben erfolgte au?erdem die Bestimmung der Textur, des pH-Wertes, des Gehaltes an Phosphat, Calciumkarbonat, Bikarbonat und Salz. Die Gehalte der Bl?tter an Eisen und anderen Mikroelementen ergaben keinen Aufschlu? über die Chloroseursache. Es bestanden auch keine gesicherten Korrelationen zwischen den NH₄-azetatl?slichen Mikroelementgehalten des Bodens und dem Auftreten der Chlorose. Eigentliche Ursache der Chlorose scheint das HCO₃ ⁻ zu sein, da sich, in der Mehrzahl der F?lle eine erh?hte Bikarbonat-Konzentration im Boden chloroseerkrankter Plantagen feststellen lie?. Aus den Ergebnissen wird geschlossen, da? in erster Linie die Verbesserung der Drainage und der Wasserführung als Ma?nahme zur Chlorosebek?mpfung in den untersuchten Plantagen erfolgen mu?. Fe- und Zn-Chelat-Spritzungen sind nur als vorl?ufige Ma?nahmen zu betrachten.

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Summary To ascertain reasons for chlorosis in madarin orchards, microelement content in leaf and soil samples from 20 representative mandarine plantages in tne Izmir-region (Turkey) have been determined. In soil samples also texture, pH and content of P, CaCO₃, HCO₃ ⁻ and salt was analyzed. Fe-, Zn- and Mn-contents of leaves did not help to clarify the reason for chlorosis. There was also no significant correlation between the amount of ammoniumacetate soluble microelements in the soil and the appearence of chlorosis. HCO₃ ⁻ seems to be the main reason of chlorosis, because its content in most of the chlorotic plantages was raised. According to these results, improvement of the drainage system as the most important step in curing chlorosis is concluded. Spraying with Fe- and Zn-chelats are considered only as preliminary steps.