Investigating physiological and biochemical
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Muhammad Abdul Qayyum UAF 2015 Soil Env Sciences
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3.1.3.1. Seedling growth
Sixty genotypes of linseed were grown under hydroponic conditions under three salinity levels including control. The bulk of data regarding growth and ionic parameters was converted to salt tolerance indices (% control) to rank the sixty linseed genotypes into salt tolerant, moderate and sensitive at two salinity levels. The data regarding growth parameters indicated that vegetative growth of linseed genotypes decreased sharply with increasing levels of salt stress. It was noted that root length, shoot dry weight, root dry weight, and shoot/root ratio significantly decreased with increasing levels of salinity, however, low salinity level (100 mM NaCl) reduced these growth parameters to lesser extent than high salinity level (200 mM NaCl). The trend between reduction of root and shoot growth of linseed genotypes under salinity was rather more interesting. It was recorded that shoot growth was hampered more than root growth in salinity stress because root length of salt stressed genotypes reduced less as compared to the root length of genotypes grown under normal conditions while a sharp decrease in shoot growth of salt stressed genotypes was recorded when compared with their non-saline counterparts. However, in two genotypes 637-72 and NO-303 (ranked salt tolerant), reduction in shoot length was the minimum and these were considered the best performing genotypes under saline conditions (Fig 3.1.1). In addition, the variation among linseed genotypes in terms of relative salt tolerance (salt tolerance index) increased from low to high salinity levels. During this study, chlorosis was observed occasionally on few plants while visual damage on plant leaves was evident at low salinity level. On the other hand, visual damage was severe at high salinity while chlorosis was observed on all plants. It was difficult to quantify the score among genotypes on the basis of visual observation and did not included in the ranking of genotypes, so data is not shown here but on the whole damage on NO-303 and 637-72 appeared less than the other genotypes. In sixty (60) linseed genotypes, half the genotypes (30) were considered salt sensitive, twenty 58 one (21) genotypes were moderately tolerant and nine (9) genotypes were ranked salt tolerant regarding their vegetative growth and biomass production (Table 3.1.2). 0 1 2 3 4 5 6 7 8 9 637 -72 NO -303 E -136 L × 10 -164 M -319 97019 1717158 NM -10 NM -14 NM -2 NM -92 -17 4506 -13 NM -4 97001 NM -6 A S T L IA -9 L × 10 -7 -1 2 × 10 -7 LA -10 -127 -1 NM -12 L × 10 -77 S -907 M - 6 -A 230 -27 -680 -4 336153 -538 -2 F R L × 10 -54 L × 10 -101 98004 L × 10 -3 F -18 -1 E 2 8 -1 NM -1 L × 10 -165 97007 6173 -8 -33 L × 10 -10 -10 L × 10 -162 RL -70 DRM -311 0173 -13 -10 NM -9 NL -31 NM -3 L × 10 -207 M -303 11 -2 g e n o ty p e C -99 -3 -115 L × 10 -10 L × 10 -29 97017 6148 -51 -12 L × 10 -103 E -96 166 -L × 10 L × 10 -10 -39 L × 10 -11 L -9 -20 -9 L × 10 -163 L × 10 -168 G P 9 8 -3 -45 % c o n tr o l Genotypes SDW RDW RL S:R total Figure 3.1.1. Graph showing the relative growth parameters of linseed genotypes (genotypes from best to worst performing) 0 1 2 3 4 5 6 7 8 L × 10 - 103 L - 9 - 20 - 9 L × 10 - 162 637 - 72 NM - 3 336153 - 538 -… L × 10 - 29 NM - 2 DRM - 311 L × 10 - 168 97001 NM - 10 E - 136 L × 10 - 165 L × 10 - 3 NO - 303 11 - 2 g e n o ty p e NM - 6 97007 L × 10 - 11 97019 G P 9 8 - 3 - 45 L × 10 - 163 NM - 92 - 17 M - 6 - A L × 10 - 10 - 10 A S T L IA - 9 M - 319 L × 10 - 77 6173 - 8 - 33 NM - 14 RL - 70 230 - 27 - 680 - 4 NM - 4 98004 L × 10 - 164 L × 10 - 10 - 39 4506 - 13 M - 303 C - 99 - 3 - 115 E - 96 L × 10 - 10 L × 10 - 54 1717158 166 - L × 10 F - 18 - 1 NL - 31 LA - 10 - 127 - 1 NM - 9 L × 10 - 7 - 1 L × 10 - 207 2 × 10 - 7 0173 - 13 - 10 L × 10 - 101 NM - 12 S - 907 97017 NM - 1 E 2 8 - 1 6148 - 51 - 12 % c o n tr o l Genotypes Na K Figure 3.1.2. Graph showing the relative ion (Na + , K + ) contents in linseed genotypes (genotypes from best to worst performing) 59 Table 3.1.2. Ranking of sixty linseed genotypes for their relative salt tolerance in terms of seedling growth parameters (shoot dry weight, root dry weight, root length, shoot/root ratio) in a cluster analysis (Ward’s minimum variance analysis) Genotypes NaCl (mM) Cluster group ranking a Sum b Genotypic ranking c Tolerance degree E-316, 637-72, 97019, NO-303 100 1 2 1 Tolerant 200 1 97001, M-319, NM-14, NM-2 100 1 3 2 Tolerant 200 2 NM-4, 4506-13 100 1 4 3 Moderate 200 3 L× 10 -103, L-9-20-9 100 1 5 4 Moderate 200 4 L× 10 -77 100 2 3 2 Tolerant 200 1 6601-6, NM-92-17, ASTLIA-9, NM-10 100 2 4 3 Moderate 200 2 2× 10 -7, NM-6, NM-12, 6173-8-33, 230-27-680-4, RL-70, NM-1 100 2 5 4 Moderate 200 3 11-2 100 2 6 5 Sensitive 200 4 LA-10-127-1, L×10-7-1, 36153-538-2FR, L× 10 -165 p 100 3 5 4 Moderate 200 2 L× 10 -10-10, DRM-311, 97007, 97017, L× 10 -3, L× 10 -207, NM-9 100 3 6 5 Sensitive 200 3 NL-31, NM-3, 100 3 7 6 Sensitive 60 200 4 `L× 10 -164, M-6-A 100 4 5 4 Moderate 200 1 E28-1, L× 10 -54, L× 10 -101, L× 10 -162, M-303, F-18-1, 98004, L× 10 -29, C-99-3-115 100 4 6 5 Sensitive 200 2 0173-13-10, L× 10 -10, 6148-51-12, L× 10 -11, S-907 100 4 7 6 Sensitive 200 3 L× 10 -168, L× 10 -10-39, E-96, 166- L× 10, GP98-3-45, L× 10 -163 100 4 8 7 Sensitive 200 4 a Cluster groups were obtained from Ward’s minimum variance cluster analysis on the means of the salt tolerance indices in seedling growth parameters (see Material and Methods). Genotypes were divided into four cluster groups at 100 mM NaCl and four clusters groups at 200 mM NaCl. The cluster group rankings were obtained from cluster means (data not shown) in the order from the highest to the lowest cluster means. b Sums were obtained from the cluster group ranking by adding the ranking numbers at the two salt levels in each genotype. c Genotypes were finally ranked based on the sums with the smallest sum being the relatively most tolerant Download 1.66 Mb. Do'stlaringiz bilan baham: 
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