Germination response of black nightshade (Solanum nigrum) to temperature and the establishment of a thermal time model

Black nightshade (Solanum nigrum L.) is one of the worst weeds in crop fields, and it spreads mainly by the dispersal of seeds. Temperature is one of the key environmental factors affecting seed germination. We investigated the seed germination response to temperature in six populations of S. nigrum from mid to northern China and derived mathematical models from germination data. The results showed that S. nigrum seeds exhibit distinct germination responses to temperature within the range of 15 to 35 °C. The optimum temperatures for the populations XJ1600, JL1697 and HLJ2134 were 30 °C, and those for the populations NMG1704, HN2160 and LN2209 were 25 °C, 20 °C and 15 °C, respectively. Based on the nonlinear fitting and thermal time models, the predicted base temperatures of the six populations ranged from 2.3 to 6.4 °C, and the required accumulated growing degree days (GDD) ranged from 50.3 to 106.0 °C·d. The base temperatures and the accumulated GDD for germination differed among populations, and there was a significant negative correlation. HLJ2134 population required a high base temperature and accumulated GDD for germination, indicating that it might highly adapted to a warmer and moister environment. Based on the different germination responses of S. nigrum populations to temperature, the thermal time model reflects an innate relationship between base temperature and accumulated GDD required for initiation of seed germination, which provides a better basis for predicting seedling emergence and the timing for optimal control of S. nigrum under field conditions.

It happened again: convergent evolution of acylglucose specialized metabolism in black nightshade and wild tomato

Plants synthesize myriad phylogenetically-restricted specialized (aka secondary) metabolites with diverse structures. Metabolism of acylated sugar esters in epidermal glandular secreting trichomes across the Solanaceae (nightshade) family are ideal for investigating the mechanisms of evolutionary metabolic diversification. We developed methods to structurally analyze acylhexose mixtures by 2D NMR, which led to the insight that the Old World species black nightshade (Solanum nigrum) accumulates acylglucoses and acylinositols in the same tissue. Detailed in vitro biochemistry - cross validated by in vivo virus induced gene silencing - revealed two unique features of the four-step acylglucose biosynthetic pathway: a trichome-expressed, neofunctionalized invertase-like enzyme, SnASFF1, converts BAHD-produced acylsucroses to acylglucoses, which in turn are substrates for the first-reported acylglucose acyltransferase, SnAGAT1. This biosynthetic pathway evolved independently from that recently described in the wild tomato S. pennellii, reinforcing that acylsugar biosynthesis is evolutionarily dynamic with independent examples of primary metabolic enzyme cooption and additional variation in BAHD acyltransferases.

Effect of processing methods on the antioxidant potentials of netlespurge (Jatropha tanjorensis) and black nightshade (Solanum nigrium) vegetables in peanut burger

Two lesser known indigenous vegetables: netlespurge (Jatropha tanjorensis) and black nightshade (Solanum nigrium) were each processed into flour samples and were incorporated into wheat flour in coating peanut. These veggie peanut burgers were analysed for their antioxidant properties such as DPPH, FRAP and Metal Chelating ability assay and their linoleic acid inhibition. Veggie peanut burger with netlespurge vegetable had values between 44.62 to 68.32%, 0.0106 to 0.0253 mg AAE/g sample and 49.03 to 63.30% for DPPH, FRAP and Metal chelating assay, respectively, while veggie peanut burger with black nightshade had values between 54.97 to 72.70%, 0.0105 to 0.0173 mg AAE/g sample and 47.13 to 64.01% for DPPH, FRAP and Metal chelating assay respectively. The result of the inhibition of linoleic acid of the peanut burger incorporated with vegetables revealed the abilities of the vegetables to inhibit propagation of peroxides up till the fourth day. Netlespurge vegetable had absorbance values of 2.3220 µm initially rising to 2.6845 µm on the fourth day and a fall absorbance value of 1.1845 µm on the sixth day while Black Nightshade vegetable had absorbance values of 2.3670 µm initially rising to 2.7490 µm on the fourth day and a fall absorbance value of 1.2355 µm on the sixth day. This study concluded that processing methods does not eliminate the antioxidative properties of vegetables and the inclusion of vegetables into peanut burgers increased their antioxidative properties.

Selectivity of herbicide oxadiazon to processing tomato and control of American black nightshade plants

ABSTRACT American black nightshade (Solanum americanum) is one of the main weeds for tomato crops. However, no herbicide approved for this crop in Brazil is effective for the control of this species and selective to tomato plants. Therefore, the objective of the present study was to evaluate the selectivity of the herbicide oxadiazon to plants of three processing tomato hybrids and the control of American black nightshade plants. Four trials were installed: one under greenhouse and three under field conditions. The greenhouse trial was conducted in a completely randomized design with four replications, using a 2x5 factorial arrangement consisting of preemergence and postemergence applications of five oxadiazon rates (75, 125, 250, 375, and 500 g ha-1) to control American black nightshade plants, and two control treatments without herbicide application. The field trials were conducted in a randomized blocks design with four replications on commercial production areas in the municipality of Cristalina-GO, Brazil. The tomato hybrids tested were Acangata 9992, H-9553, and HMX 7885, one in each trial. The treatments consisted of application of five oxadiazon rates (125, 250, 375, 500, and 625 g ha-1) at pre-planting of the tomato seedlings, and a control treatment without herbicide application. The application of oxadiazon in preemergence, in the greenhouse, was more efficient for controlling American black nightshade plants under greenhouse conditions than the application on plants with 2-3 leaves. However, the weed control was satisfactory (>90%) when rates up to 246 g ha-1 were used, in both application times. The herbicide application caused no visual injuries to tomato plants under field conditions, and had no negative effect on fruit yield. Therefore, the herbicide oxadiazon was highly selective to the three processing tomato hybrids when applied at pre-planting, using rates of up to 625 g ha-1. The herbicide presented excellent control of American black nightshade plants, using rates from 125 to 371 g ha-1.

Investigation on Supercritical CO2 Extraction of Black Nightshade Berries (Solanum nigrum Linn.)

A set of supercritical extractions (SCE) using carbon dioxide (CO2) has been performed on Solanum nigrum Linn. A design of experiment (DoE) using Box-Behnken was applied to investigate the influential parameters on SCE. The relationship between extraction parameters (i.e., temperature, time, and pressure) and extraction products (i.e., phenolics-TPC, alkaloids-TAC, and flavonoids-TFC) was evaluated. It was found that temperature and pressure are the most influencing parameters in the SCE. Both give a synergistic effect in increasing the extraction yield. The optimum SCE conditions are 333 K, 30 min, and 240 bar; with extraction, yields expressed as TPC, TFC, and TAC are 55.1677 mg GAE/g extract, 28.0308 mg QE/g extract, and 5.9460 mg HYE/g extract, respectively. Solubility data correlations were done by using Chrastil’s model. The adjustable parameters of Chrastil’s model were found to be consistent with their physical meaning and can be applied in the SCE of Solanum nigrum Linn.

Development and life history parameters of Typhlodromus recki (Acari: Phytoseiidae) feeding on Tetranychus urticae (Acari: Tetranychidae) at different temperatures

Typhlodromus recki (Acari: Phytoseiidae) was collected from aubergines, pepper, black nightshade and jimsonweed plants infested with spider mites from a pesticide-free vegetable garden in Denizli, Turkey. The biology and life table parameters for T. recki feeding on Tetranychus urticae (Acari: Tetranychidae) at different temperatures (15, 20, 25, 30 and 35 °C) were determined. The results showed that total preadult periods of T. recki at 15, 20, 25, 30 and 35 °C were 19.6±0.51, 9.4±0.16, 7.6±0.14, 5.7±0.14 and 4.5±0.08 days, respectively. The longest oviposition period was 23.5 days at 20 °C. Total fecundity of T. recki significantly differed between the constant temperatures and the highest was observed at 20 °C (28.6 eggs/female) and 25°C (23.5 eggs/female). Although females survived for 26 days at 35 °C, only four females laid eggs for 1 day. Thus, 35 °C is not suitable for the reproduction of T. recki. Total longevity of female was the longest at 15°C (59.5 days) and 20 °C (51.3 days) whereas male total longevity was the longest at 15°C (53.2 days). The intrinsic rate of increase (r) and finite rate of increase (λ) were numerically the highest at 30 °C (0.17 and 1.18 d-1), but there was no statistical difference observed between 25 and 30 °C for both r and λ values. The net productive rate was significantly highest at 20, 25 and 30 °C. The longest mean generation time occurred at 15 °C (42.6 days) and the shortest was at 35 °C (8.0 days). After some field trials, Typhlodromus recki could potentially be considered in the biological control agent of T. urticae.

Biological performance and oviposition preference of tomato pinworm Tuta absoluta when offered a range of Solanaceous host plants

The tomato pinworm Tuta absoluta (Lepidoptera: Gelechuidae) is native to South America and has now become the main tomato pest in Europe, Africa and Asia. The wide range of host plants attacked by this pest has been reported as one of the main reasons for the success of this important insect species. However, the information currently available on the biological performance of T. absoluta on Solanaceae has been obtained from a limited number of host species. The Solanaceae family is composed of thousands of species, many of which are potential hosts for T. absoluta. Our results showed that the highest oviposition rates occurred on cultivated tomato plants, potato and wild tomato. The lowest rates occurred on “gilo”, “jurubeba”, green pepper and pepper. The highest survival rates of the immature stages occurred on potato and the lowest on pepper, green pepper and “jurubeba”. Female fertility, following infestation of the different plant species, was highest for insects that developed on tomato or potato and the lowest rates were seen on American black nightshade. The net reproductive rate and the intrinsic growth rate were highest on potato and tomato. Cluster analysis grouped tomato and potato as highly susceptible to attack, American black nightshade, juá, eggplant, gilo and wild tomato as moderately susceptible, whilst pepper, green pepper and jurubeba were categorized as resistant to T. absoluta. These results clearly demonstrate that the choice of solanaceous host plant species has a direct impact on the fitness parameters of the tomato pinworm as well as survival potential, dispersion and establishment at new sites. These results are important for the planning of integrated pest management strategies.