Three cotton (Gossypium hirsutum L.) germplasms (DP62, 84027, and 84033) were used to investigate the physiology of salt tolerance. Lines 84027 and 84033 were developed from the parental line DP62 and showed superior vigor under varying NaCl conditions (0.5 to 2.0 M) during germination and emergence. Proline levels increased in the leaves of all germplasms in response to increasing salinity. Varietal differences in proline levels did not reflect their variation in salt tolerance. Several physiological characteristics were also evaluated under non-saline condition in the greenhouse. There were no significant differences among germplasm sources for all parameters measured. However, salinity reduced transpiration rate, increased leaf diffusive resistance and leaf temperature for all lines. Ribosomal-RNA levels in all germplasms were evaluated after seeds were stressed for 24 hrs in various concentrations of NaCl and then germinated under normal conditions for 72 hrs. Ribosomal-RNA levels were inversely related to salt concentrations. Line 84033 followed by line 84027 had highest ribosomal-RNA content than the parental line DP62 when averaged over the four salt concentrations. Sodium content (ppm/g FW) and Cl⁻ content (ppm/g FW) were evaluated in microsomal and cell walls fractions as well as a cytoplasmic fraction which consisted of vacuoles, mitochondria, and plastids. The Cl⁻ ion exhibited a greater consistency in a concentration shift from one fraction to another as a function of time than did the Na⁺ ion. As a result, there may be a correlation between the drop in ribosomal-RNA and the amount of Cl⁻ in the microsomal fraction. Other parameters measured in the germinating seed were soluble protein (globulin), insoluble proteins (prolamin and glutelin) and fiber percentage. Variations within the germplasms were shown to exist. This study shows that even among lines that have been selected for salt tolerance from a single variety, the possibility exists that each of these lines may have a different mechanism to cope with salt stress.

Artificially aged and non-aged seeds of 22 grain sorghum (Sorghum bicolor L.) F₁ hybrids and their F₂ and F₃ generations were evaluated for germination salt tolerance. Six of the hybrids, along with their F₂ and F₃ generations, were tested for emergence salt tolerance. Effects of seed production environments on germination salt tolerance were also studied using F₂ generations of 12 sorghum hybrids produced under full-season irrigation, limited irrigation, and double-cropping conditions. Germination tests were conducted in a growth chamber, on trays, while the emergence test was conducted in a greenhouse in flats filled with sand. The experiments were conducted under non-saline and saline conditions in randomized complete block designs. Artificial seed aging resulted in significant reductions in germination percentages under both non-saline and saline environments. The overall mean reduction in germination caused by seed aging was more than twice as much under salinity stress as under the non-stress conditions (48 vs. 17%), indicating differential effects of salinity on different quality seeds. Entries that appeared to be resistant to seed aging also had higher germination percentages under salinity stress. Seed production environment influenced germination performance in both non-saline and saline environments. The overall mean germination percentages of sorghum seeds produced under three different field environments were significantly different from one another. Significant differences were observed in germination and emergence percentages within F₁, F₂, and F₃ generations. Except for the F₁ entries, however, emergence index differences within the F₂ and F₃ generations were not significant. Correlations between germination and emergence percentages in the non-saline and saline treatments were generally nonsignificant. This suggests that germination and emergence responses of sorghum may vary under different salinity levels and different environments.

Field and greenhouse experiments to determine the response of grapes to saline irrigation water were conducted. The goal of this research were: (1) to study the effect of salinity on grape and wine quantity and quality and (2) to evaluate the degree of salt tolerance of some of the grape rootstocks. For the greenhouse study, seven grape rootstocks were grown in the soil columns irrigated with three levels of salinity, EC of 0.45, 2.5, and 5 mmhos/cm. The later two waters were prepared by adding MgSO₄ and CaC1₂ salts to tap water with EC of 0.45 mmhos/cm. Shoot growth, pruning weight, leaf area, and trunk diameter were significantly reduced by salinity. Reduction in shoot growth and pruning weight were more pronounced than leaf area and trunk diameter. Maximum ECₑ values (1007 reduction in growth) varied from 8.81 mmhos/cm for 41B rootstock to 16.43 mmhos/cm for Ramsey rootstock. Maximum ECₑ for Barbera (Vitis vinifera) was 11.04 mmhos/cm. Based on percent reduction in growth, the relative tolerance of grapes could be arranged as follows: Ramsey > 5BB > SO4 > 1613 > Barbera > 99R > 41B. The field study included two sources of water and six grape rootstocks which were grafted to Barbera. Two sources of irrigation water were city and well water with EC of 0.42 and 2.6 mmhos/cm, respectively. The response of grapes to salinity was evaluated by fruit yield and pruning weight. Well water application significantly reduced fruit yield and pruning weight. The average fruit yield and pruning weight of Barbera grapes with all the rootstocks decreased by 49.5 7e and 26.7 7e with the well water compared to the city water, respectively. Must and wine analysis indicated that salt treated grape had higher total acidity and lower pH. Alcohol of the wines was not affected uniformly by treatment. Except for 99R rootstocks, the color of the wines were darker in city water than well water. Quality of wine from 3309 rootstock was lowered considerably by well water. With well water, only Barbera wine from 5BB rootstock appeared to be commercially acceptable. The six rootstocks differed from each other in their ability to growth in saline condition. Barbera grape grafted on 5BB and Ramsey rootstocks showed higher tolerance to salinity than Barbera on 99R, 3309, Harmony, and 41B rootstocks.

The succulent, annual euhalophyte, Salicornia bigelovii was grown in 1, 10, 35, 45 and 60 ppt Instant Ocean. This range represents approximately 1/35 to nearly twice the salinity of seawater. The plants in the 4 highest salinities had common final dry weights and seed yields of about 60 and 11 g, respectively, while the 1 ppt plants had 28 and nearly 5 g, respectively. The water relations data reflected the growth and seed production of the plants. The plants in the 4 higher salinities had water potentials sufficient to generate large import gradients and osmotic potentials which contributed to substantial turgors. The 1 ppt plants had a gradient like the rest, but a very low turgor of 0.11 MPa which was barely 23% of that of the lowest of the other treatments. Higher salinities resulted in slightly greater organic and inorganic osmotica contents. Overall, these results suggest a relatively fixed genetic response to a wide range of salinities, as well as an inability to function well at very low salinities. No plant grown at 0 ppt was ever able to reproduce. Therefore, this plant is an obligate halophyte. Experiments in the plant's native coastal estuary indicated meristem water potentials fluctuate with the tides, although they remain about 1.5 MPa below the corresponding soil water potentials. The plants occupy a discrete elevational range throughout the estuary, spending about 1/3 of their daylight hours submerged, and apparently never see dryness. Phenotype differences in the estuary suggest that, within the habitat, pacing and consequent resource domination may be important parameters affecting plant size and possibly fitness. Nitrogen, which is characteristically rare in this and other estuaries, may be critical in this regard. The plants produce large quantities of glycine-betaine, which may be for simultaneous osmoticum use and nitrogen storage. Most roots occur in the first 3 inches of soil. A mechanism is proposed, based on highly efficient compartmentation at the cellular level and the shuttling of organic osmoticum across the tonoplast, by which the tidally based cyclical water potentials could be explained.

No description available.

The inhibitory effects of NaCl, L- and D-asparagine, and asparagine substrate analogs, beta-aspartyl hydroxamate (AAH) and albizziin, alone or in combination on Columbia Arabidopsis seed germination and seedling survival were characterized under aseptic conditions. Germination on an agar medium supplemented with inorganic nutrients was prevented by 200 mM NaCl, 20 mM L-asparagine, 60 mM D-asparagine, 1.4 mM AAH, or 8 mM albizziin. Established seedlings were generally more tolerant to these chemicals than germinating seeds. Exogenous L- and D-asparagine partly reversed the inhibitory effects of NaCl on seed germination. L-asparagine also partly reversed AAH inhibition of germination. A M2 seed bank was created from the self-pollinated progeny of ethyl methane sulfonate treated seeds. Arabidopsis mutants having increased tolerance to NaCl and AAH, but not albizziin, were successfully selected from this seed bank.

Exogenous application of BA (0, 50, 100 mg ul--1) had no significant effects on tolerance of chili peppers to salt (--0.75 MPa NaCl:CaCl₂, 3:1, w/w) as measured by vegetative and reproductive weights, numbers of reproductive structures, transpiration and total chlorophyll. When peppers were applied with microliter amounts of ¹⁴C labelled benzyladenine (BA; 44,400 dpm 1⁻¹), BA was translocated primarily acropetally from the site of application. Regardless of application site, translocated BA was ported primarily to expanding leaves, and BA was more readily absorbed by leaf as opposed to stem surfaces. Exogenous application of BA (0, 50, 100 mg ul⁻¹) had no significant effects on tolerance of chili peppers to salt (-0.75 MPa NaCl:CaCl₂, 3:1, w/w) as measured by vegetative and reproductive weights, numbers of reproductive structures, transpiration and total chlorophyll.

Yeung Chi Ching. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 123-134). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledges --- p.iv / Table of contents --- p.v / List of Tables --- p.vii / List of Figures --- p.ix / Chapter Chapter 1: --- Introduction --- p.1 / Chapter Chapter 2: --- Mode of reproduction of Mikania micrantha / Chapter 2.1 --- Introduction --- p.15 / Chapter 2.2 --- Literature review --- p.16 / Chapter 2.3 --- Materials and methods --- p.19 / Chapter 2.4 --- Results --- p.23 / Chapter 2.5 --- Discussions --- p.35 / Chapter Chapter 3: --- Effect of sodium chloride on seed germination of Mikania micrantha / Chapter 3.1 --- Introduction --- p.42 / Chapter 3.2 --- Materials and methods --- p.44 / Chapter 3.3 --- Results --- p.48 / Chapter 3.4 --- Discussions --- p.58 / Chapter Chapter 4: --- Sodium chloride as a herbicide for Mikania Micrantha in Mai Po Marshes / Chapter 4.1 --- Introduction --- p.60 / Chapter 4.2 --- Literature Review --- p.61 / Chapter 4.3 --- Materials and methods --- p.74 / Chapter 4.4 --- Results --- p.80 / Chapter 4.5 --- Discussions --- p.113 / Chapter Chapter 5: --- Conclusions --- p.118 / References --- p.123

Includes bibliographical references

Bibliography: leaves 151-187. / xvii, 187 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Agriculture and Natural Resource Sciences, 1993