پتوں کا سرخ ہونا ایک عضویاتی بیماری ہے جو زیادہ دباؤ اور غذائی اجزاء ی کمی سے ہوتی ہے. موسم کے آخر میں یہ ایک قدرتی عمل ہے اور یہ کسی توجہ کا مرکوز نہیں ہے. تاہم، اگر سرخ ہونے کا عمل موسم کی ابتدا میں ہو تو ، حفاظتی اقدام کرنے چاہیےReddening 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.Leaf color is determined by pigment content and concentration. Pigments commonly present in cotton leaves include chlorophylls, carotenoids, tannins and anthocyanins. Differences in pigment properties give each pigment color characteristics; for example, chlorophylls a and b absorb light in the blue and red regions while reflecting light in the green. Similarly, carotenoids are visually associated with yellows and reds, tannins with browns, and anthocyanins with reds and purples.Fig. 1: An inverted leaf which has been shaded by a Tennessee T shows an increased production in anthocyanin in areas exposed to direct sunlight. Fig. 1: An inverted leaf which has been shaded by a Tennessee T shows an increased production in anthocyanin in areas exposed to direct sunlight.The content and concentration of these pigments can additionally provide insight into the plant’s current or past growing conditions. For instance, reddening of a leaf can indicate the plant has experienced abiotic or biotic stress such as excessive radiation (Fig. 1) or a nitrogen (N) deficiency (Fig. 2). Since changes in pigments within the plant also changes the color of the leaf, visual observations of the canopy collected through the growing season can be used to gauge plant health. In the case of a reduction of chlorophyll due to an N deficiency, a reduction in chlorophyll is directly associated with a shift from dark green to light green leaf color. Whether used subconsciously or consciously, pigment content and concentration has been used for hundreds of years to diagnose stresses, including nutrient deficiencies, disease, pest damage, and water deficits/excesses.What pigment causes the red color in cotton leaves?The main pigment associated with red colored leaves in cotton is anthocyanin. This pigment is the same compound which produces the red color noted in deciduous forests in the fall before they shed their leaves. Depending upon the cause of the reddening and timing during the season, the color may be caused by either an increase in anthocyanin content or by a reduction in green chlorophyll content which otherwise masks the red color of anthocyanin. dissipate excess light energy which could potentially damage leaf structures,serve as an antioxidant to scavenge free radicals caused by stress, and possibly,reduce water potential of the leaf to facilitate osmotic adjustment under some stresses.When are red leaves not a concern?The presence of ‘reddish’ leaves in your crop does not always justify action or indicate yield has been lost. An example of this is an increase in anthocyanin during senescence (Fig. 3).Fig. 3: Red leaves commonly appear late in the season as leaves age or plants begin to senesce. When occurring very near or after cracked boll, red leaves may indicate the plant has been properly managed. Fig. 3: Red leaves commonly appear late in the season as leaves age or plants begin to senesce. When occurring very near or after cracked boll, red leaves may indicate the plant has been properly managed.Anthocyanin serves as a phyto-protectant during this process and thereby helps improve the productivity of nutrient re-partitioning activities. Leaf reddening or even purpling late in the se ed should be reduced to prevent unnecessary damage to the crop.Under certain circumstances, it is thought that excessive radiation can additionally cause an increase in anthocyanin in the upper side (adaxial) of leaves (Fig. 6). Prolonged periods of cloudy or rainy weather followed by an abrupt shift to clear, high-irradiance conditions may trigger this response. Similarly, rain or irrigation events followed immediately by periods of high temperatures and sunlight may cause ‘sunscald’. Other phenomena causing leaves to increase anthocyanin production are generally more localized. Chimera, a genetic mutation which is occa f this occurs early in the season, plants contained within the circular or slightly irregular area may die shortly after the strike. Later in the season, strikes typically result in the rapid death of the apical meristem and upper vegetation while subtending and mainstem leaves at lower nodes are not terminated but are characterized by an increase visible anthocyanin.