Darrell J. Weber

Ecophysiology of high salinity tolerant plants.

Contributing authors.- Preface.- Foreword.- 1. How salts of sodium, potassium and sulfate affect the germination and early growth of Atriplex acanthocarpa (Chenopodiaceae) B. Gaylord, T. Egan.- 2. Halophyte eed germination M.A. Khan, B. Gul.- 3. Salt tolerance of some potential forage grasses of Cholistan desert of Pakistan M. Ashraf et al.- 4. Variability of fruit and seed-oil characteristics in Tunisian accessions of the halophyte Cakile maritima (Brassicaceae) M.A. Ghars et al.- 5. Salt tolerant plants from the great basin region of the United States D.J. Weber, J. Hanks.- 6. Role of calcium in alleviating salinity effects in coastal halophytes B. Gul, M.A. Khan.- 7. Calorespirometric metabolism and growth in response to seasonal changes in temperature and salt B.N. Smith et al.- 8. Evaluation of anthocyanin contents under salinity (NaCl) stress in Bellis perennis L. R.A. Khavari-Nejad et al.- 9. A comparative study on responses of growth and solute composition in halophytes Suaeda salsa and Limonium bicolor to salinity X. Liu et al.- 10. Alleviation of salinity stress of some Brassica species M. Ozturk et al.- 11. Saline tolerance physiology in grasses K.B. Marcum.- 12. Localization of potential ion transport pathways in thesalt glands of the halophyte Sporobolus virginicus Y. Naidoo, G. Naidoo.- 13. Cellular responses to salinity of two coastal halophytes with different whole plant tolerance: Kosteletzkya virginica (L.) Presl.and Sporobolus virginicus (L.) Kunth X. Li et al.- 14. Eco-physiological studies on Indian desert plants: effect of salt on antioxidant defense systems in Ziziphus spp. N. Sankhla et al.- 15. Sabkha edge vegetation of coastal and inland sabkhat in Saudi Arabia H.-J. Barth.- 16. Analysis of the soil conditions in salt grass (Distichlis spicata (L.) Greene) wild populations in semiarid coastal zone of Mexico A. Escobar-Hernandez et al.- 17. Comparative salt tolerance of perennial grasses S. Gulzar, M.A. Khan.- 18. Commercial application of halophytic turfs for golf and landscape developments utilizing hyper-saline irrigation M. DePew, P.H. Tillman.- 19. Salt tolerance of floriculture crops C.T. Carter, C.M. Grieve.- 20. Utilization of salt-affected soils by growing some Acacia species M.Y. Ashraf et al.- 21. Soil remediation via salt-conduction and the hypotheses of halosynthesis and photoprotection N.P. Yensen, K.Y. Biel.-22. Mechanism of cash crop halophytes to maintain yields and reclaim saline soils in arid areas H.-W. Koyro et al.- 23. Halophyte uses for the twenty-first century N.P. Yensen.- 24. Halophyte research and development: What needs to be done next? B. Boer.

Structure of HC-toxin, a cyclic tetrapeptide from helminthosporium carbonum

Abstract Helminthosporium carbonum , which is pathogenic to maize, produces a metabolite, HC-toxin ( 1 ), with selective toxicity to susceptible host genotypes. Resistant genotypes and non host plants are tolerant. The structure of 1 (C21H32N4O6) was determined as cyclo [(2-amino-9,10-epoxy-8-oxodecanoyl)-alanyl-alanyl-prolyl] based upon spectral evidence.

Germination of dimorphic seeds of Suaeda moquinii under high salinity stress

Suaeda moquinii (Torrey) Greene (desert blite), a succulent shrub in the family Chenopodiaceae, is widely distributed in salt marshes of the western United States. Suaeda moquinii produces dimorphic seeds (soft brown and hard black). Both types of seeds were collected from a salt marsh in Faust, Utah. Experiments were conducted to determine the seed germination responses of the black and brown seeds to salinity and temperature. Brown seeds were found to be one of the most salt tolerant at the germination stage when compared to other halophytes. Brown seeds germinated (30%) at 1000 mM NaCl, but only a few black seeds germinated (8%) at 600 mM NaCl. Seed germination occurred in most saline treatments at the lowest thermoperiod (5–15˚C) tested. In some salinity treatments (600, 800, 1000 mM), further increases in temperature resulted in progressively decreased seed germination. Brown seeds germinated better and had a higher germination rate (germination velocity) than black seeds at all thermoperiods. The highest rate of germination of black seeds occurred at the lowest thermoperiod (5–15˚C). Recovery of germination for black seeds when transferred to distilled water after being in various salinity treatments for 20 days was nearly complete (82–100%) at the lowest thermoperiod (5–15˚C) but decreased with increase in the temperature. Brown seeds recovered substantially (59–97%) from salinity at all thermoperiods. Regression analyses indicated significant differences between the germination recovery of the black and brown seeds.

Seed Germination in Relation to Salinity and Temperature in Sarcobatus Vermiculatus

Sarcobatus vermiculatus (Hook) Torrey is a leaf succulent, sodium-accumulating shrub usually found in saline substrates of the Great Basin desert, Utah, USA. Laboratory experiments were conducted to determine the effect of salinity (0, 200, 400, 600, 800 and 1000 mM NaCl) and temperature (day/night: 5/15, 10/20, 15/25, 20/30, and 25/35°C) on seed germination. S. vermiculatus showed 100% germination in non-saline controls, at all thermoperiods. Percentage and rate of germination decreased with increases in salinity and few seeds germinated at even 1000 mM NaCl. High salinity exposure caused the loss of viability at higher temperature regimes, while some recovery was recorded in low salinity treatments.

Distribution of VA mycorrhiza on halophytes on inland salt playas

The value of mycorrhizal association for higher plants has been well established. However, the impact of high salinity on the mycorrhizal relationship has not been investigated to any great extent. Inland salt playas represent an opportunity to test the impact of salinity because it is possible to obtain a gradient by following a transect from the centre of the salt playa to the higher outer zones. In a salt playa near Goshen, Utah, the sodium concentration ranged from 27,150 ppm in the centre to 25 ppm in the outer zone. In the playas with sodium concentrations of 20,000 ppm, no mycorrhiza were detected on the halophytes and no spores of mycorrhizal fungi were found in the soil. One percent of the roots of salt grass in soils containing 8,450 ppm of sodium were mycorrhizal. In soils containing 622 ppm of 45 percent of the roots of a salt-tolerant grass (hybrid ofAgropyron repens × Agropyron spicatum) were mycorrhizal. Halophytes such asSalicornia pacifica var.utahensis which are among the most salt tolerant halophytes of the inland salt playas rarely had mycorrhizal roots. The mycorrhizal associations appear to be very limited in inland salt playas with sodium content.

Alleviation of salinity and dark-enforced dormancy in Allenrolfea occidentalis seeds under various thermoperiods

The effect of germination-regulating chemicals on the alleviation of salinity-enforced germination inhi- bition of Allenrolfea occidentalis (S.Wats.) Kuntze at various thermoperiods in complete darkness was investigated. There was poor germination at cool temperatures and germination-regulating chemicals were ineffective in alleviat- ing this effect. Germination in the dark increased progressively with increase in temperature and maximum germi- nation was obtained at 25-35°C thermoperiod. Ethephon and fusicoccin (FC) substantially reverted dark-induced inhibition at moderate thermoperiods. All other germination-regulating chemicals were more effective at moderate temperature, while germination was not specifically different from control at higher temperature. Salinity-enforced germination inhibition was partially alleviated by all growth regulators at the higher temperature regime (25-35°C). Best reversal was obtained with the application of ethephon and FC. Our results suggest that temperature is the most critical factor influencing the germination of Allenrolfea seeds. Allenrolfea occidentalis seeds germinated better at higher than at lower temperatures in the dark and all of the growth-promoting compounds showed their maximum reversal effect at higher temperatures.

Influence of salinity and temperature on the germination of Kochia scoparia

Kochia scoparia is one of the most common annual halophytes foundin the Great Basin. Seeds were collected from a population growing in asalt playa at Faust, Utah and were germinated at 5 temperature regimes(12 h night/12 h day, 5–15 °C, 10–20 °C, 15–25 °C,20–30 °C and 25–35 °C) and 6 salinities (0, 200, 400,600, 800 and 1000 mM NaCl) to determine optimal conditions forgermination and recovery of germination from saline conditions after beingtransferred to distilled water. Maximum germination occurred in distilledwater, and an increase in NaCl concentration progressively inhibited seedgermination. Few seeds germinated at 1000 mM NaCl. A temperatureregime of 25 °C night and 35 °C day yielded maximumgermination. Cooler temperature 5–15 °C significantly inhibited seedgermination. Rate of germination decreased with increase in salinity.Germination rate was highest at 25–35 °C and lowest at5–15 °C. Seeds were transferred from salt solutions to distilled waterafter 20 days and those from high salinities recovered quickly at warmertemperature regimes. Final recovery germination percentages in high salttreatments were high, indicating that exposure to high concentration ofNaCl did not inhibit germination permanently.

Effect of salinity on the growth and ion content of Salicornia rubra

Salicornia rubra is a stem succulent annual halophyte, which is widely distributed in the saltpans of Northern Utah playas. This study reports the effect of salinity (0, 200, 400, 600, 800, and 1000 mM NaCl) on the growth, succulence, osmotic and water relations of the species under greenhouse conditions. Fresh and dry weight of plants increased with an increase in salinity. Optimal growth of S. rubra plants were recorded at 200 mM NaCl and the growth declined with a further increase in salinity. Both sodium (Na) and chloride (Cl) contents of plants increased with an increase in salinity, while Ca2+, Mg2+, and K+ content decreased. Succulence of shoots increased at low salinity and decreased at high salinity. Water potential of plants become more negative with an increase in salinity. The Fv/Fm ratio was more affected by higher salinity and irradiation stress during growth.

Element Accumulation Patterns in Foliose and Fruticose Lichens from Rock and Bark Substrates in Arizona

Abstract Growth form and substrate influences on elemental accumulation patterns were investigated in four lichen species. Two fruticose species (Usnea amblyoclada on rock and Usnea hirta on bark) and two foliose species (Flavoparmelia caperata on rock and Flavopunctelia flaventior on bark) were collected below Massai Point in Chiricahua National Monument in southeastern Arizona, U.S.A. Samples were analyzed for 14 elements. A two-way ANOVA model was used to examine the relationships between substrate and growth form (independent variables) on element accumulation (dependent variable) patterns in lichen samples. In the ANOVA model the growth form variable was significant for K, Ca, Ti, Ba, Fe, Ni Cu, Zn, Pb, Rb, and Sr while the substrate variable was significant for K, Ti, Mn, Fe, Ni, Rb, and Sr. A significant interaction between the two class variables was observed for P, K, Ti, Mn, Fe Ni, Rb, and Sr. Accumulation of sulfur appeared to be independent of both growth form and substrate influences. In this study growth form was a key factor affecting element accumulation patterns in lichens. It is proposed that thallus continuity and orientation, which partially define growth form characteristics, influenced the accumulation of elements from airborne and substrate sources.

Inheritance of hydrocarbons in subspecific big sagebrush (Artemisia tridentata) hybrids

Abstract Volatile compounds of the subspecies tridentata and vaseyana of Artemisia tridentata along with their F 2 s hybrids were characterized and identified. These compounds segregated in the F 2 s. Methacrolein and thujone characterize ssp. tridentata ; camphene, camphor, and 1,8-cineole characterize ssp. vaseyana . Results of this study taken together with previous work suggest that low values for the bitter volatile methacrolein might be combined with high biomass and nutritive quality characteristics from hybrid progeny.