فهرست مقالات Environmental stresses

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  1 - Effects of Paclobutrazol Application on Plants as a Chilling Stress Ameliorator
  Mahroo Mojtabaie Zamani
  Paclobutrazol ((2RS, 3RS)-1-4(-chlorophenyl)-4,4-dimethyl-2-1,2,4-triazol-1-yl-penten-3-ol) is a member of the triazole family, that protects plants against various stresses. Probably paclobutrazol affects the morphology and biochemical and physiological reactions of pl چکیده کامل

  Paclobutrazol ((2RS, 3RS)-1-4(-chlorophenyl)-4,4-dimethyl-2-1,2,4-triazol-1-yl-penten-3-ol) is a member of the triazole family, that protects plants against various stresses. Probably paclobutrazol affects the morphology and biochemical and physiological reactions of plant by regulating the level of endogenous hormones (inhibition of gibberellin biosynthesis, increase of abscisic acid, decrease of ethylene, change of cytokinin content and modulation of their transporter genes). Morphological effects of paclobutrazol are include reduction of stem length and lower internode length, increase in stem physical strength, thicker stems, increase in leaf thickness, thicker epicuticular wax layer on leaf, reduction of leaf area, larger chloroplasts, and increase in root growth. Biochemical effects of paclobutrazol include the increase of proline, chlorophyll and carotenoids, polyamines, protein, and soluble carbohydrates and the detoxification of reactive oxygen species through the increase of antioxidant activities. These changes increase the tolerance of plants to environmental stress. One of the environmental stresses that disrupts the natural activity of plants, and the use of paclobutrazol helps to moderate its negative effects, is chilling stress. Chilling stress, especially in tropical and sub-tropical species, through changes in biochemical and physiological processes, causes negative effects on plants. Paclobutrazol protects plants against chilling stress and ameliorates chilling damage by strengthening the antioxidant defense system, regulating hormone levels, and improving photosynthesis system. In this article, the role of paclobutrazol to alleviate the adverse effects of cold stress in plants is examined. Moreover, various morphological, biochemical and physiological processes leading to improved crop production under the effect of paclobutrazol are discoursed in detail. پرونده مقاله
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  2 - Morphological and Physiological Traits of <i>Catharanthus roseus</i> L. at Different Irrigation Intervals as Affected by Salicylic Acid Application
  Davood Hashemabadi Zahra Asadi Beigzadeh-Mahaleh Firoozeh Pourzarnegar
  The effects of varying irrigation intervals (I) and foliar application of salicylic acid (M) on morphological and physiological traits of Catharanthus roseus L. were studied in a factorial experiment based on a randomized complete design with three replications. The exp چکیده کامل

  The effects of varying irrigation intervals (I) and foliar application of salicylic acid (M) on morphological and physiological traits of Catharanthus roseus L. were studied in a factorial experiment based on a randomized complete design with three replications. The experimental treatments consisted of four irrigation intervals [2 days (I1), 4 days (I2), 6 days (I3) and 8 days (I4)] and foliar application of 200 mgL-1 salicylic acid (SA) at three frequencies [0 (M0), one (M1) and two (M2) times]. Among the morphological traits, treatment I2M2 resulted in the greatest number of flowers (25.66 flowers), the fewest leaf abscissions (3.8), and the highest root fresh weight (1.181 g); I1M0 resulted in the highest plant height (154 cm), leaf number (36 leaves), internode length (9.243 mm), shoot fresh weight (8.636 g), and shoot dry matter (26.20%); and I1M2 resulted in the largest flower diameter (1.176 mm), node number per plant (16.66 nodes), plant fresh weight (9.366 g), and root dry matter (30.03%). Among physiological traits, I1M0 was related to the highest chlorophyll b, total chlorophyll, and petal anthocyanin. The highest and lowest proline contents were obtained from I3M2 and I2M0, respectively. The lowest MDA content of 1.42 nmolg-1fresh weight (FW) was observed in I4M1 and the highest SOD activity of 88 IUg-1FW was obtained from I3M0. POD activity was lowest in I2M0 and highest in I4M2. In total, given the detrimental impacts of water deficit stress at irrigation intervals of 6 and 8 days, it is recommended that SA be applied to improve the growth of Catharanthus. roseus L. پرونده مقاله
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  3 - تنش های زنده و غیرزنده در گیاهان زراعی و دارویی
  مهدی ملک پور عبدالمجید لیاقت
  <strong>زمانی که گیاهان در معرض انواع تنش</strong><strong>&shy;</strong><strong>های محیطی قرار می‌گیرند، سبب کاهش بهره&shy;وری محصولات کشاورزی می&shy;شود. تنش&shy;های محیطی بر دو نوع تنش&shy;های زنده و غیرزنده</strong><strong> </strong><strong>تقسیم&shy;بندی می&shy;شود. چکیده کامل

  <strong>زمانی که گیاهان در معرض انواع تنش</strong><strong>&shy;</strong><strong>های محیطی قرار می‌گیرند، سبب کاهش بهره&shy;وری محصولات کشاورزی می&shy;شود. تنش&shy;های محیطی بر دو نوع تنش&shy;های زنده و غیرزنده</strong><strong> </strong><strong>تقسیم&shy;بندی می&shy;شود. تنش‌های غیرزنده شامل تنش دما، سرما، اشعه ماوراء بنفش، شوری، غرقابی، خشکسالی (کم آبی) و فلزات سنگین است که منجر به از بین رفتن گیاهان زراعی در سطح جهان می&shy;شود. در حالی که تنش زنده به آسیب&shy;های ناشی از حشرات، گیاه خواران، نماتدها، قارچ&shy;ها، باکتری&shy;ها و علف&shy;های هرز اشاره دارد. گیاهان به همه این عوامل محیطی واکنش نشان می‌دهند. برای مقابله با این تنش&shy;ها استراتژی&shy;ها و راهکارهایی توسط گیاهان ایجاد می‌شود. گیاهان زمانی که تنش&shy;های محیطی فعال می&shy;شوند، پاسخ&shy;های سلولی لازم را ایجاد می&shy;کنند. تحقیقات متعددی برای تعیین و درک تحمل به تنش در گیاهان انجام شده است که برای درک پیچیدگی پاسخ گیاه به تنش&shy;های زنده و غیرزنده ضروری می&shy;باشد.</strong> پرونده مقاله