Control of Substrate Water Availability Using Soil Sensors and Effects of Water Deficit on the Morphology and Physiology of Potted Hebe andersonii

Many plant producers tend to overwater crops to prevent water stress and salt-induced damage. These practices waste irrigation water and cause leaching that harms the environment and increases production costs. In order to optimize water consumption and minimize the environmental impact of plant production, this study aimed to determine the physiological and morphological responses of Hebe andersonii to three substrate volumetric water contents (49%, 39%, and 32%). The experiment was conducted in a greenhouse with an irrigation protocol that consisted of adding small volumes of water to avoid leaching while monitoring substrate moisture with dielectric soil sensors. The results showed that moderately low substrate moisture improved the water-use efficiency, while growth was significantly reduced under more severe water deficit conditions (but without leaf chlorosis or abscission). The photosynthetic activity of Hebe was primarily controlled by the stomatal aperture, which was co-determined by the substrate moisture and seasonal temperature. Hebe leaves promoted non-photochemical quenching when carbon assimilation was limited by a water deficit, and accumulated solutes through an osmotic adjustment process (especially Cl−, Na+, and K+) to maintain their water status. Overall, Hebe andersoni cv. Variegata could successfully grow and improve its water-use efficiency in low substrate moisture and under a non-draining irrigation regime.

Performance of Two Thin Epoxy Overlays on New Concrete under Laboratory and Outdoor Exposure Conditions

Thin epoxy overlays are used for improving the condition and extending the service life of bridge decks. The tensile bond pull-off strength, evaluated as per ASTM C1583, is used as the performance indicator. A failure in the substrate with a tensile strength of 250 pounds per square inch (psi) or greater is considered acceptable. However, the performance of in-service bridge decks when evaluated shows inconsistent results. Such studies failed to record and correlate the parameters that influence overlay performance during testing to clarify the observed variations. Laboratory studies by several researchers have documented a distinct performance difference when the overlays are exposed to room temperatures in comparison with elevated temperatures. However, the most influential parameters, such as the variation of substrate moisture against temperature and epoxy softening under elevated temperatures, were not measured and correlated to the observed performance. This study was initiated to provide clarification of the observed performance differences by evaluating the impact of concrete age at the time of epoxy application, concrete mix ingredients, exposure conditions, concrete microstructure development, and substrate moisture and temperature on the performance of two epoxy overlays. Experimental results confirm that (i) the performance of epoxy overlays improves when the concrete mix contains slag and (ii) substrate moisture vapor pressure and epoxy softening under elevated temperature negatively affect the overlay performance.

Biomasa kultivara engleskog ljulja zasijanih nakon 5 godišnjeg skladištenja sjemena na različitim temperaturama

Seeds of two perennial ryegrass (Lolium perenne L.) cultivars (diploid ‘Bartwingo’ and tetraploid ‘Calibra’) were stored in hermetically sealed glass jars at four different temperatures (-80, -20, 10 and 20°C) for five years. After the storage period the seeds were sowed in containers filled with commercial substrate. Initial growth and development occurred under natural sunlight and manual watering to maintain optimum substrate moisture. After 60 days of vegetation plants were taken from the substrate, developed plants were counted, their roots were washed and whole plants were measured for shoot and root dry-weight and total biomass.Stems and leaves per plant were counted too. The research has revealed significant effects (p<0.01) of storage temperature, cultivar and their interaction to all of the investigated traits. When averaged over cultivars the highest values were observed upon storage temperature of -20°C for all the traits except root dry-weight which did not differ between -20 and -80°C. The lowest values of all investigated traits were observed upon storage at 20°C. When averaged over storage temperatures, diploid cultivar had greater number of stems and leaves and the tetraploid one had greater root dry-weight, shoot dry-weight and total biomass.

Optimized production of tannase and gallic acid from fruit seeds by solid state fermentation

Purpose: To investigate the possibility for gallic acid production from different tannin-rich fruit seeds using Aspergillus oryzae via solid-state fermentation. Methods: Fruit seeds of apple, guava, tamarind, black plum and watermelon were analyzed to estimate the synthesis of an enzyme tannase and its product gallic acid. Various physicochemical parameters were optimized to increase the gallic acid yield. Gallic acid was extracted by Soxhlet apparatus and identified by Fourier-transform infrared spectroscopy (FTIR). It was quantitatively determined by high performance liquid chromatography (HPLC). Results: Amongst the various substrates tested, black plum seeds gave the highest activity of 34.40 U/g for tannase and 16.66 mg/g for gallic acid under optimized physicochemical conditions, i.e., 1:3 substrate: moisture ratio, 30 °C, 96 h incubation period and pH 5.5. Addition of carbon source had a negative effect on production while ammonium sulphate (0.2 %) as nitrogen source increased the yield of both products. The gallic acid produced was 98.5 % pure, compared to the standard. Conclusion: Production of tannase and gallic acid via solid-state fermentation conditions has been optimized in vitro. The optimized conditions can be utilized on a commercial scale for economically viable production of gallic acid.

Influence of Temperature and Moisture Content on Thermal Performance of Green Roof Media

The influence of moisture content on substrate thermal conductivity at different temperatures was investigated for four different commercially available substrates for green roofs. In the unfrozen state, as moisture content increased, thermal conductivity increased linearly. In the phase transition zone between +5 and −10 °C, as temperature decreased, thermal conductivity increased sharply during the transition from water to ice. When the substrate was frozen, thermal conductivity varied exponentially with substrate moisture content prior to freezing. Power functions were found between thermal conductivity and temperature. Two equally sized, green roof test cells were constructed and tested to compare various roof configurations including a bare roof, varying media thickness for a green roof, and vegetation. The results show that compared with the bare roof, there is a 75% reduction in the interior temperature’s amplitude for the green roof with 150 mm thick substrate. When a sedum mat was added, there was a 20% reduction in the amplitude of the inner temperature as compared with the cell without a sedum mat.

Effect of incubation temperature and substrate moisture on embryonic development, hatchling phenotypes and post-hatching growth in the Reeves’ Turtle, Mauremys reevesii

Background Reeves’ Turtles (Mauremys reevesii) are economically important in aquaculture in China. Understanding the effects of incubation temperature and substrate moisture on embryos and hatchlings is of great significance for improving the artificial culture of M. reevesii. However, available studies have not yet determined the thermal and hydric optima for M. reevesii eggs, and the potential interaction between the two factors. Methods In this study, eggs of M. reevesii were incubated at five temperature levels (23, 26, 29, 32 and 35 °C, fluctuation range ± 0.5 °C). In each temperature level, there were three substrate moisture levels (1:0.5, 1:0.9 and 1:1.2, weight ratio of vermiculite to water). Thus, a total of 15 combinations of temperature and moisture were used to examine the effects of incubation temperature and substrate moisture on incubation duration, hatching success, hatchling phenotypes, post-hatching growth and hatchling survival. Results Substrate moisture did not significantly affect most development parameters (except incubation duration and carapace width of hatchlings). Eggs incubated at low moisture level (1:0.5) had a longer incubation duration and produced hatchlings with smaller carapace widths than those incubated at medium (1:0.9) or high (1:1.2) moisture levels. Incubation temperature had a significant effect on incubation duration, hatching success, hatchling phenotypes and hatchling survival. Incubation duration decreased as incubation temperature increased. Eggs incubated at 23, 26 and 29 °C showed higher hatching success than those incubated at 32 and 35 °C. Hatchlings incubated at 32 °C were smaller in body size and mass than those incubated at 23, 26 and 29 °C. At 12 months of age, incubation temperature had no long-lasting effect on body mass, but hatchlings incubated at 23 and 35 °C had lower survival rates than those incubated at 26, 29 and 32 °C. For the development of embryos and hatchlings, the interaction between incubation temperature and substrate moisture was not significant. Conclusions Our results indicate that incubation temperature has a significant influence on the development of embryos and hatchlings of M. reevesii, while substrate moisture only significantly affects the incubation duration and carapace width of hatchlings. The combination of an incubation temperature of 29 ± 0.5 °C and a substrate moisture level of 1:1.2 represented optimal incubation conditions in this experiment. Such incubation conditions are helpful in obtaining higher hatching success, shorter incubation duration and higher survival rates for this aquaculture species.