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Title of Thesis

Investigation Of Differences In Salt Tolerance Mechanisms In Contrasting Bread Wheat Genotypes

Author(s)

Zulfiqar Ahmad Saqib

Institute/University/Department Details
Institute Of Soil & Environmental Science, / University Of Agriculture, Faisalabad
Session
2010
Subject
Soil Science
Number of Pages
184
Keywords (Extracted from title, table of contents and abstract of thesis)
Mechanisms, Genotypes, Ion, Partition, Salinity, Tolerance, Stress, Sodium, Wheat, Investigation, Bread, Contrasting

Abstract
The genotypic differences regarding Na+ accumulation and transport in plant along with physiological response to improve salt tolerance were studied in bread wheat genotypes.Four wheat genotypes; Kharchia-65, SARC-3, S-9476 and S-8189 were grown under salt stress (75 and 150 mM NaCl) in nutrient solution with five replications. Shoot dry weight, relative growth rate (RGR), chlorophyll index, leaf water relations, Na+ content and transport in plant were measured.The increase in NaCl stress decreased all growth parameters, however, variations were observed among genotypes. Kharchia-65, S-9476 and SARC-3 had better growth and water relations compared to salt sensitive genotypes S-8189. The low rate of Na+ transport and better ability to restrict Na+ in the root was main reason of genetic variation among different genotypes, especially, when growth characteristic did not vary significantly under salt stress. Na+ partition was also recorded in wheat genotypes as salt sensitive genotypes had higher Na+ accumulation in shoot while it was reverse in tolerant ones. The differences in root Na+ were not significant among all genotypes. In many crop plants, over-accumulation of Na+ in shoot is the main cause of yield reduction due to toxicity. In this study, wheat genotypes differed mainly because of low rates of Na+ uptake and transport from root to shoot. Therefore, in this study, it was concluded that wheat genotypes with contrasting leaf Na+ uptake rates and transport from root to shoot had resulted in differences in salinity tolerance. The wheat genotypes having ability to reduce Na+ accumulation in shoot by retaining it at root level had better salt tolerance. The genotypes with the highest Na+ uptake had lower chlorophyll, more electrolyte leakage, and a slightly lower RGR.

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1,596 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 CONTENTS

 

 
48 KB
2

1

INTRODUCTION

 

1
45 KB
3 2 REVIEW OF LITERATURE

2.1 Agricultural productivity affected by salinity
2.2 Salinity in Pakistan
2.3 Effects of salinity on plant
2.4 Biochemical changes in response to salt stress
2.5 Two-phase salinity model for effects on growth
2.6 Effect of salinity on wheat
2.7 Salt tolerance
2.8 Mechanisms of salt tolerance in wheat and other plants
2.9 Use of salt tolerant plants
2.10 Genetic diversity among plant genotypes for salt tolerance
2.11 Previous approaches to improve salt tolerance in wheat
2.12 Research Needs
2.13 Objectives of thesis

3
373 KB
4 3 STUDY-1: GENETIC VARIATION FOR TRANSPORT, UPTAKE AND DISTRIBUTION OF NA+ AND ITS INFLUENCE ON SALT TOLERANCE IN WHEAT

3.1 Introduction
3.2 Materials and Methods
3.3 Results
3.4 Discussion

37
 331 KB
5 4 STUDY-2: SOLUTE ACCUMULATION AND DISTRIBUTION ALTERED LEAF PHONOLOGY AND DEVELOPMENT AS FUNCTION OF STRESS TOLERANCE IN CONTRASTING WHEAT GENOTYPES

4.1 Introduction
4.2 Materials and Methods
4.3 Results
4.4 Discussion

56
316 KB
6 5 STUDY-3: VALIDITY OF GROWTH RATE, ION CONTENTS AND WATER RELATIONS IN ASSOCIATION WITH GRAIN YIELD IN WHEAT GENOTYPES UNDER SALT STRESS

5.1 Introduction
5.2 Materials and Methods
5.3 Results
5.4 Discussion

78
347 KB
7 6 STUDY-4: RELATIONSHIP BETWEEN K+ HOMEOSTASIS AND PHYSIOLOGICAL DETERMINANTS CONFERRING SALT TOLERANCE IN BREAD WHEAT GENOTYPES

6.1 Introduction
6.2 Materials and Methods
6.3 Results
6.4 Discussion

103
347 KB
8 7 GENERAL DISCUSSION

 

126
75 KB
9 8 REFERENCES

136
187 KB