Pakistan Research Repository


Ismail, Shoaib (1998) PHYSIOLOGY OF SALT TOLERANCE IN SOME FODDER PLANTS. PhD thesis, University of Karachi, Karachi.



The effect of salinity was studied on some aspects of growth, biochemical changes and accumulation of minerals in different species of atriplex sesban, S. Formosa, Leucaena leucocephala and Acacia ampliceps in (i) lysimeter, (ii) at coastal sandy area and (iii) inland saline soils. Plants grown in lysimeter and at coastal sandy area were irrigated with saline water of various concentrations, whereas, those of inland saline soil with canal water DRUM POT CULTURE (LYSIMETER STUDIES) Studies were carried out in Atriplex nummularia, A cinerea and A. amnicola in drum pots (lysimeter) filled with sand irrigated with non-saline (Control) and saline water (10-30% dilutions of sea water; EC: 0.63-14.00 dS.m-1) Growth of plants were monitored by harvesting the plants at 15 cms height from soil surface at 3-monthly intervals. Fresh and dry weight of clipped shoot showed maximum biomass production at 20% sea water (EC: 10.16 dS.m1-) after which a reduction started at various salinity levels. Fresh shoot biomass of and 7.25 Kg Plant-1 Yr-1 was observed in A. nummularia, A. cinerea respectively, producing 1.98, 2.5 and 2.4 Kg Plant-1 Yr-1 dry matter A. amincola and A. cinerea showed an increase in moisture content with increase in salinity level, whereas, non-significant differences was observed in the woody saltbush. A nummularia. The amount of toal chlorophyll increased with increase in salinity in all species of Atriplex studied with a reduction in chlorophyll ‘b’ fraction Protein content in all the atriplex species either showed an increase or remained unaffected at low salinity levels of 10-40% sea water (ECie:0.63-19.50 dS.m-1) whereas at higher dilutions of 60-100% sea water (ECiw:26.50-41.00 dS.m-1) a reduction was observed. A. amnicola and A. nummularia showed an accumulation of praline with increase in salinity levels, whereas A. cinerea showed non-significant difference between control and all salinity treated plants. Slight reduction in sugar content of A. amnicola and A. nummularia was observed in plnats irrigated with 10-40% sea water (ECie:4.01-19.50 dS.m-1), however at higher salinities of 60-100% (ECiw:26.50-41.00 dS.m-1) a significant increase was evident. On the other hand, sugar content in A. cinerea increased progressively with the increase in salinity of the irrigation medium The amount of Na+ ions increased, whereas, K+ deceased with increase in salinity of irrigation water in all the three Atriplex species showing maximum concentration in A. nummularia. The accumulation of Ca++ and Mg++ was reduced under salinity A gradual reduction in plant height, stem diameter and biomass was observed in tree species, Leucaena leucocephala, Sesbania sesban and Acacia ampliceps with increase in salinity levels of irrigation water. S. sesban showed comparatively better salt tolerance and produced highest shoot biomass at all salinity levels. L. leucocephala and S. sesban showed a reduction in chlorophyll ‘a’ under salinity. The amount of protein in L. leucocephala increased up to 30% sea water, whereas, S. sesban showed a significant increase up to 10% salinity followed by a reduction at higher salinity levels. The amount of protein under different salinity levels however, still remained slightly higher than that of control plants. L. leucocephala showed an accumulation of praline with increase in salinity levels, whereas, S. sesban showed non-significant differences between control and salinity treated plants Data on reproductive physiology of S. sesban and L. leucocephala showed that number of pods/plant increased in the former and decreased in the latter species with increasing salinity of the irrigation. However, the number of seeds/pod showed an increase in both species All the tree species S. sesban, L. leucocephala and Ac. Ampliceps showed an increase in the Na+ content with increase in salt treatment, but the concentration were less than that of saltbushes. K+ content decreased in L. leucocephala, whereas, an increase was evident in S. sesban and Ac. Ampliceps under saline conditions, however, he amount of both Ca++ and Mg++ was higher than control plants in all the three species Comparison of both organic and inorganic composition of seeds and fruit wall of S. sesban and L. leucocephala showed a higher concentration of protein and sugar in the seeds as compared to fruit wall. Protein content increased with salinity, in both seeds and fruit wall, whereas, sugar content showed a reduction. The amount of mineral ions (Na+, K+, Ca++ and Mg++) were also higher in fruit wall as compared to seeds. Better germination percentage was observed under saline conditions in L. leucocephala seed lots obtained from plants grown through 30% sea water irrigation, than those irrigated with non-saline water (control) Field studies at coastal sandy area Field studies were undertaken at coastal sandy area of Bhawani (Baluchistan). The plants were irrigated with underground salinity water (ECiw:14-17 dS.m-1) Eight different species of Atriplex tow species of Sesbania and one species of Leucaena were grown with non-saline and saline water irrigation Shoot biomass of Atriplex species obtained from clippings were recorded for two consecutive years. A amnicola produced highest shoot biomass (ca. 20 T Ha-1 Yr-1) during the first year under saline water irrigation, whereas, A. nummularia, all other Atriplex species exhibited higher biomass when irrigated with saline water. Biomass productivity after first year harvest showed a reduction during subsequent harvest Woody species of saltbushes A. isatidesa, A. nummularia and A. halimus exhibited higher sugar content as compared to shrubby species. However, the concentration of sugar in plants irrigated with saline water statistically higher in A. cinerea, A. nummularia and A. halimus then the rest of the species where non-significant differences were present The amount of total chlorophyll was also higher in all species of Atriplex irrigated with saline water except A. lentiformis which showed a reduction of 7.83% over non-saline control. The ratio of chlorophyll a/b increased under salinity treated plants in A. lentiformis, A. halimus, A. undulate and A. nummularia. With exception of A. Amnicola, A. halimus and A. mummulatia, all the other species showed an increase in protein content in plants irrigated with saline water. A. isatidea showed a maximum increase of 64.45%. Overall, the highest concentration of praline under saline conditions was recorded in A. isatiea followed by A. nummularia, whereas, minimum amount was found in A. cinerea Increase in Na+ content in the leaves was statistically significant only in A. cinerea, A. lentiformis, A. nummularia and A. paludosa, whereas, other species exhibited non-significant differences. With exception of A. amnicola and A.nummularia all the other Atriplex species exhibited an accumulation of K+ under saline treatment. The amount of Ca++ and MG++ were higher in plants irrigated with saline water, particularly in woody saltbush species Leucaena leucocephala grown under saline conditions showed a reduction of only 11.70% in plant height after one year of growth as compared to non-saline water irrigation. Stem diameter also showed similar trend. Both the chlorophyll fractions ‘a’ and ‘b’ and their cumulative amount showed an increase of approximately 11% in salinity treated plants. Protein content in this species showed an increase whereas, sugar content showed a decrease under saline conditions. The amount of praline showed a significant (P<0.05) reduction of 44.19% in salinity treated plants as compared to non-saline control. A significant increase in Na+ and decrease in Mg++ ions was observed under saline conditions, whereas, K+ and Ca++ exhibited non-significant differences Both the plant height and stem diameter in sesbania Formosa did not show any significant differences in growth rate during summer season (May-October) between non-saline and saline water treatments, but a reduction in stem diameter was observed from Nov-April, under saline water irrigation. Non-significant differences for chlorophyll content between non-saline and salinity treated plants were observed with a reduction of ca. 3.07% in salinity treated plants for both the chlorophyll fractions. Protein and sugar content showed a reduction of 9.8% and 23.11% respectively, in saline water treated plants, whereas, a 3-fold increase was observed in praline content. Na+ and K+ exhibited an increase of 64.28 and 72.53% respectively, in plants irrigated with saline water, Mg++ showed a non-significant reduction. The concentration of Ca++ was highest under salinity as compared to the other cations Sesbania sesban grown for one-year period showed a reduction of 24% in plant height when irrigated with saline water as compared to non-saline control. Stem diameter exhibited similar trend, but showed lesser reduction. Chlorophyll, protein and sugar content showed a reduction to control plants. The amount of praline on the other hand, shwed a significant increase of 86% in saline water irrigated plants as compared to control plants. Except Mg++ all the cations showed non-significant changes between control and saline water treated plants. The concentration of Ca++ was highest followed by Mg++, Na+ and K+ FIELD EVALUATION OF ATRIPLEX SPECIES AT INLAND SALINE SILTYSOILS OF SUJAWAL Field trials were undertaken at inland silty saline wasteland of Sujawal, where seven different species of Atriplex were grown in six different salinity blocks. Since the whole experimnetal area was quite heterogeneous with reference to soil salinity, it was divided into six blocks according to ECe. At low salinity Block-I the ECe ranged from 15.02-23.71 dS.m-1 and at high salinity Block-VI from 64.75-103.70 dS.m-1, at 0.50 cms soil profile Growth was monitored by measuring the shoot volume at 6-monthly intervals. The rating of plant volume after one year at low salinity blocks was in the order, Atriplex amnicola > A. cinerea > undulate > A. vesicaria > A. canescens > A. halimus > A. stocksii. However, at hight salinity blocks the ratings were, A. cinerea > A. halimus > A. undualta > A. Vesicaria > A. amnicola > A. canescens > A. Stocksii. Shoot valume during second year was lower in most of the species Shoot biomass showed maximum productivity in salinity Block-II (ECe: 27.38-41.25 dS.m-1) in both the years where the species could be ranked in the following order, A. cinerea > A. amnicola > A. undualata > A. Vesicaria > A. canescens > A. halimus > A. Stocksii. Maximum average fresh shoot biomass calculated was 69.3 T Ha-1 Yr-1 for A. amnicola and minimum for A. stocksii (6.6 T Ha-1 Yr-1). At high salinity Block-VI, the species ranked in order of shoot biomass was A. undualta > A. cinerea > A. halimus > A. amnicola > A. vesicaria > A. canescens > A. stocksii, with maximum values of 10.45 T Ha-1 Yr-1 for A. undualata and minimum for A. stocksii (2.2 T Ha-1 Yr-1) Plant survival after harvest varied in both the years. The mortality percentage ranged from 10-20% after first harvest in low salinity Block-I, whereas, it was ca. 60% in high salinity Block-VI. After second harvest, a further reduction of 20% in plant survival was observed in low salinity Block-I with no significant effect at high salinity block-VI Growth of Atriplex species at different salinity blocks over a period of time did not exhibit any significant change in the soil characters. Varied responses were observed at different soil profile for various species In the light of above mentioned results, it is suggested that cultivation of selected salt tolerant plants could be economically feasible at barren coastal sandy area and in inland silty saline wasteland for providing forage/fodder and fuel wood

Item Type:Thesis (PhD)
Uncontrolled Keywords:salt tolerance, fodder plants, atriplex sesban, s. formosa, leucaena leucocephala, acacia ampliceps, salinity, atriplex nummularia, a cinerea, a. amnicola, sesbania sesban
Subjects:Biological & Medical Sciences (c) > Biological Sciences(c1) > Paleo-botany(c1.9)
ID Code:1114
Deposited By:Mr. Muhammad Asif
Deposited On:03 Jan 2007
Last Modified:04 Oct 2007 21:04

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