Morphological Responses of Viola Accessions to Nutrient Solution Application and Electrical Conductivity.

Growing of ornamental flowering plants represents an important sector of horticulture. Viola × wittrockiana (garden pansy) is used in garden beds and borders due to their colorful blooming, which occurs in early spring and late autumn. Nowadays, breeders focus on applying different nutrient solutions to improve the quality, flowering, and ornamental properties of plants, yet electrical conductivity (EC) level is an important fact to know. It is known that higher EC levels can inhibit plants' growth. In the present study, pansy seedlings were subjected to different EC nutrient solutions 1 (control), 2, 3.5, 5, and 6.5 mS cm-1 EC to assess the positive or negative effects regarding the plant's growth and development. The results indicated that an appropriate EC level of nutrient solution can have a positive effect on growth parameters, as well as on the flowering of plants. According to the hierarchical clustering, the used EC nutrient solutions significantly influenced the growth, number of shoots and leaves and the inflorescences number. From the present study results, it can be concluded that even though all EC levels increased growth parameters compared with control, the greatest results were obtained in plants under the effect of the 5 mS cm-1 of EC.

Endosymbiotic Bacterial Diversity of Corn Leaf Aphid, Rhopalosiphum maidis Fitch (Hemiptera: Aphididae) Associated with Maize Management Systems.

In this study, different maize fields cultivated under different management systems were sampled to test corn leaf aphid, Rhopalosiphum maidis, populations in terms of total and endosymbiotic bacterial diversity. Corn leaf aphid natural populations were collected from traditionally managed maize fields grown under high agricultural and natural landscape diversity as well as conventionally treated high-input agricultural fields grown in monoculture and with fertilizers use, hence with low natural landscape diversity. Total bacterial community assessment by DNA sequencing was performed using the Illumina MiSeq platform. In total, 365 bacterial genera were identified and 6 endosymbiont taxa. A high abundance of the primary endosymbiont Buchnera and secondary symbionts Serratia and Wolbachia were detected in all maize crops. Their frequency was found to be correlated with the maize management system used, probably with fertilizer input. Three other facultative endosymbionts ("Candidatus Hamiltonella", an uncultured Rickettsiales genus, and Spiroplasma) were also recorded at different frequencies under the two management regimes. Principal components analyses revealed that the relative contribution of the obligate and dominant symbiont Buchnera to the aphid endosymbiotic bacterial community was 72%, whereas for the managed system this was only 16.3%. When facultative symbionts alone were considered, the effect of management system revealed a DNA diversity of 23.3%.

Impact of Foliar Fertilization on Growth, Flowering, and Corms Production of Five Gladiolus Varieties.

Degraded and salt affected soils are appearing more often in cultivated areas. These specific problems could reduce nutrient uptake, which can result in quality and yield loss of the cultivated plants. In order to cope with this pedo-climatic condition growers are applying fertilizers; however, due to inadequate application, soil degradation will continue. Five Gladiolus varieties were subjected to foliar fertilization treatments to assess the effect on the plant's growth parameters, vase durability and daughter corm production. Our results indicate that plants treated with foliar fertilization show significant increase in the measured parameters, flower stem length, vase durability and daughter corm production. In conclusion, our study suggests that application of foliar fertilization can increase Gladiolus plants decoration and propagation, even with a smaller footprint on nature.