No abstract

Nanosilica is a versatile nanomaterial suitable as, e.g., drug carriers in medicine, fillers in polymers, and fertilizer/pesticide carriers and potentially a bioavailable source of silicon in agriculture. The enhanced biological activity of nanosilica over quartz sand has been noted before; it is directly related to the altered physicochemical properties of the nanoparticles compared to those of the bulk material. Therefore, it is feasible to use nanosilica as a form of plant stimulant. Nanosilica synthesis is a relatively cheap routine process on the laboratory scale; however, it is not easily scalable. Largely for this reason, studies of nanosilica fertilizers are scarce. This study will focus on industrial-scale silica nanoparticle production and the application of nanosilica as a plant stimulant in maize. A variant of the sol–gel method is used to successfully synthesize nanosilica particles starting from silica sand. The resulting particles are in the size range of 16–37 nm with great purity. The potential of nanosilica as a plant stimulant is demonstrated with the increased quantity and quality of maize crops.

Trà mi Thưởng (Camellia thuongiana Luong, Ann Le & Lau) thuộc họ Chè (Theaceae) đã được mô tả và vẽ hình, đây là một loài trà mi hoa vàng mới, phân bố ở xã Đoàn Kết, huyện Đạ Huoai, tỉnh Lâm Đồng. Trên cơ sở dữ liệu hình thái xác nhận loài mới thuộc sect. Chrysantha.

Applied Research on climate is one of the highly practical research directions for sustainable economic development. At the same time, it makes contribution to the rational exploitation and use of natural resources, protecting the environment for certain territory in order to obtain efficient agricultural production. The article applies the method of zoning agro-climate by Luset tool parameterized with meteorological, pedigree and topographic factors. Calculation results show that: Tuyen Quang province is divided into 4 main agro-climatic regions: the highly adaptive area is about 281,406 ha, accounting for 48.5% of the total area of the province; The adaptive area is about 164,088 ha, accounting for 28.3%; Less suitable area is about 70,813 ha, accounting for 12.2% and non-adapted area is about 64,375 ha, accounting for 11.1%.

A new species of the genus Camellia L. (Theaceae) from Southern Vietnam is described and illustrated under the name Camellia proensis. Morphological differences between C. proensis and closely related species in the genus Camellia L. (sect. Piquetia) were identified. C. proensis is easily distinguishable from C. honbaensis, C. piquetiana and C. longii by the yellow flowers; from C. dalatensis by the glabrous twigs and leaves; from C. dongnaiensis by light yellow flowers; from C. sonthaiensis by mature fruit flat-globose, 4.0–5.5 cm tall and 8.5–10.0 cm wide. Ecological environment and distribution were also provided for this new species. The images and type specimens of this species were processed and stored in Vietnam (holotype, isotypes, DLU).