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Home > Time Course Changes in Metabolite Accumulation and Their Implications for Heat Stress Tolerance in Maize Zea Mays L. Seedlings

Time Course Changes in Metabolite Accumulation and Their Implications for Heat Stress Tolerance in Maize Zea Mays L. Seedlings

Thesis Info

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Author

Mahmood, Saqib

Program

PhD

Institute

University of Agriculture

City

Faisalabad

Province

Punjab

Country

Pakistan

Thesis Completing Year

2010

Thesis Completion Status

Completed

Subject

Natural Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1558

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727611745

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Maize shows reduced crop stand under relatively suboptimal conditions, the main reason for this is sensitivity of bud tissue to temperature fluctuations and salinity at sowing time. The aim of these studies was to explore the physiological and biochemical occurring at seedling stage in a time course manner. The determinations were made on growth, photosynthetic pigments, accumulation of osmolytes, oxidative damage and antioxidants, secondary metabolites and nutritional quality characteristics in shoot and root of two differentially heat stress tolerant varieties of maize. Results revealed that reduction in length, fresh and dry weight of shoot and root and loss of chlorophylls and carotenoids in the leaves were the explicit determinants of heat damage. The heat tolerance of maize was associated to greater accumulation of glycinebetaine followed by free proline. As evident from H 2 O 2 and MDA data, heat stress produced oxidative stress on both the varieties, although lowly in the tolerant one. Enhanced or steady state levels of niacin, ascorbic acid and riboflavin and enhanced ability of reducing powers led to the alleviation of oxidative damage on the maize plant. Among the secondary metabolites, enhanced synthesis of flavonoids and anthocyanins and saponin was closely related to the heat tolerance of maize. As for nutritional quality characteristics, heat stress reduced the crude fiber, starch, oil and proteins contents and led to an overall reduction in the accumulation of nitrate, phosphate and K, and led to a hampered nutritional value and metabolizable energy in both the varieties, but tolerant maize was superior for these attributes. In short, heat tolerance in maize was associated greater photosynthetic pigments levels and better metabolic adjustment, which resulted in better nutritional quality of the vegetative parts for use as fodder for the animals. All these changes were more precise in the shoot.
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رشوت ستانی

رشوت ستانی

                رشوت ستانی ایک جرم ہے۔ایسا جرم جو مجرم کو امید دیتا ہے بلکہ یقین کہ وہ بالکل بے قصور ہے۔ اس میں ایک فرد کی تیسرے فریق کو عام طور پر جو کوئی اتھارٹی رکھتا ہے،(کسی سرکاری بندے کو یا نجی ادارے) کو رشوت دیتا ہے تا کہ وہ اس کے ذریعے فائدہ اٹھا سکے۔اس طرح وہ رقم مختلف قسم کے تحائف ،جاندار یا بے جان تحائف یا مختلف اقسام کی صورت میں دی جا سکتی ہے۔ صرف اور صرف ذاتی مفاد کے لیے اگلے کو خوش کر دینا بلکہ اس کے گلے میں اپنی رشوت کے ذریعے گھنٹی باندھ دینا۔رشوت دینے کا مقصد یہی ہوتا ہے کہ رشوت لینے والا ایسی کاروائی کرے اور ایسا کیس بنا کر پیش کرے جس میں قانون کو بھی اندھا ثابت کرنے میں کوئی کسر باقی نہ رہے اور معاملہ فرد کے حق میں ہو جائے۔بعض اوقات رشوت دینے کا مقصد خود کو ٹھیک ثابت کرنے کا نہیں ہوتا بلکہ اس لیے بھی ہوتا ہے کہ ہم پر حکومت کرنے والے ہمیشہ کے لیے ناکارہ ہو جائیں اور ہر عمل سے پہلے رشوت دینے والے کا سوچیں۔

                ایک مستقل سرگرمی جس میں اگلے کو اپنا غلام بنا لیا جاتا ہے،اسی کی وجہ سے معاشرتی مسائل بڑھتے جا رہے ہیں۔ یہی وجہ ہے کہ آج ہر شعبہ زندگی  میں سفارش،رشوت  اور لوٹ مار کا بازار گرم نظر آتا ہے۔دوسروں کی دل آزاری کرنا، اس کی حق تلفی کرنا نہ صر ف حقوق العباد کی نفی کرتے ہیںبلکہ اس کے ذریعے ہم حقوق اللہ سے بھی انصاف نہیں کرتے۔افسوس صد افسوس اسلام کے معیار کو بھلا کر معاشرے کی اقداروں کو نظر انداز کر کے آج ہم اس رشوت جیسے جرم کو مزید اضافے کی طرف لے جا رہے ہیں۔

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Kipling’s Depiction of the Great Game Between British India and Czarist Russia

This article provides valuable information about the living conditions of Muslims of the Pak-Afghan Region in the context of revisiting Rudyard Kipling’s view of the Great Game of the 19th century between Great Britain and Russia that roughly continued for about a century beginning in the second decade of the 19th century to the signing of the Anglo Russian convention in 1907. In this respect his famous novel, Kim (1901) has been critically examined to establish the political content of his creative work. Coupled with the appreciation of the novel as a great work of art with its many facets and themes, views of Edward Said have been juxtaposed to arrive at a conclusion that the novel is also a celebration of imperialism. In today’s scenario in Central Asia particularly Afghanistan, a revisit of Kipling is an interesting revelation. The discussion also reveals the similarities of the tussle of two centuries back to the realities in the region today. This insight as we appreciate Kipling’s masterpiece novel proves even more eye-catching and real. This paper also examines Peter Hopkirk’s works on the Great Game to historically asses the dialectics of the imperial struggle between the two super powers of the time. In this connection, a brief discussion is available on the three Anglo-Afghan Wars as well as the conflict in Kashgharia. This article presents an overview of the view head by Russians on the conflict which they call Tournament of Shadows or Bolshya Igra involving spies and military personnel. A fresh look at Kipling’s works in general and his novel Kim, in particular, helps explore the very essentials of the working of Imperialism and empire-building, which is the main stay of this paper. A deeper look would understandably unfurl big powers rivalry in general, and the present day security situation in Asia in particular, by going through the works of a great writer; the first Englishman and the youngest recipient for Nobel Prize in Literature (1907).  

Role of Endophytic Bacteria Containing Carbonic Anhydrase in Improving the Photosynthesis and Plant Biomass of Cereals at Different Moisture Regimes

Climate change is one of the serious threats to food security throughout the world especially in arid and semi-arid regions, affecting agricultural productivity. Rapid changes in global climate such as alteration in rain fall pattern and increase in temperature lead to severe drought stress that limits the crop production by reducing photosynthetic rate and suppressing plant growth. Endophytic bacteria containing carbonic anhydrase may improve plant growth and elicit tolerance under water deficit stress by enhancing the photosynthesis in plants. Carbonic anhydrase (CA) catalyzes the reversible conversion of atmospheric carbon dioxide into bicarbonate, first substrate of photosynthesis in C3 and C4 plants. Therefore, present study was conducted to assess the potential of drought tolerant CA containing endophytic bacteria for improving photosynthesis and plant biomass of cereals under different moisture regimes. One hundred and fifty bacterial isolates were isolated form two cereals (wheat and maize) and tested for their ability to tolerate PEG-induced water deficit conditions. Fifty isolates exhibiting higher drought tolerance from each crop were further analyzed for CA activity. Ten drought tolerant isolates with higher CA activity were further assessed for growth promotion in wheat (C3) and maize (C4) plants. Isolates WR2, WS11 and WL19 showed higher photosynthetic rate and plant growth in both wheat cultivars; however, increase was more for Uqab-2000 than Fsd-2008 under PEG- induced water deficit conditions. Moreover, isolates MR17, MS1 and MG9 gave significant increase in photosynthesis and plant growth in both maize hybrids, especially for H2 hybrid under PEG-mediated water stress. Selected isolates from both crops were labeled with Gus and tested for plant growth promotion as well as colonization efficiency in wheat and maize under water deficit stress. Inoculation of selected isolates showed significant results for photosynthesis, growth and colonization efficiency of wheat and maize under well watered (100% FC) and stressed (70 and 40%) conditions especially for Uqab-2000 and H2. In the same ways, isolates WR2, WS11 and WL19 gave significant results for growth, physiology and yield of wheat under field condition where water deficit stress was induced by skipping irrigation at tillering, flowering and grain filling stage. On the other hand, inoculation with isolates MR17, MS1 and MG9 improved growth under normal and stressed conditions which were induced by withholding irrigation at vegetative and reproductive stage of maize. Selected isolates also proved to be efficient auxin producer and p-solubilizer under normal and stressed conditions. These isolates were identified as Bacillus sp. In separate study, it was observed that endophytic bacterial isolates carrying CA activity AR4 and AR14 (belonged to Microbacterium sp. and Psychrobacter sp., respectively) also stimulated the expression of various genes and transcription factors in Arabidopsis thaliana under normal as well as PEG-induced water deficit conditions. Therefore, it can be suggested that inoculation of endophytic bacterial isolates (WR2, WL19 for wheat and MR17, MG9 for maize) is good for enhancing photosynthesis and plant biomass under water deficit conditions. Moreover, multi-site field experiments for these isolates are suggested for evaluating the successful performance in field. However, molecular studies are required to confirm role of bacterially synthesized CA in photosynthesis.