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Title of Thesis

Time Course Changes In Metabolite Accumulation And Their Implications For Heat Stress Tolerance In Maize (zea Mays L.) Seedlings

Author(s)

Mrs. Saqib Mahmood

Institute/University/Department Details
Faculty Of Sciences / University Of Agriculture, Faisalabad
Session
2010
Subject
Botany
Number of Pages
113
Keywords (Extracted from title, table of contents and abstract of thesis)
Glycinebetaine, Time, Associated, Stress, Greater, Accumulation, Course, Seedlings, Implications, Tolerance, Enhanced, Metabolite, Maize, Changes

Abstract
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 H2O2 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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566 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 CONTENTS

 

 
84 KB
2

1

INTRODUCTION

 

1
107 KB
3 2 REVIEW OF LITERATURE

 

5
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4 3 MATERIALS AND METHODS

 

17
 143 KB
5 4 RESULTS AND DISCUSSION

 

30
360 KB
6 5 SUMMARY

 

85
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7 6 LITERATURE CITED

87
168 KB