Search

Diatomaceous earth is an organic naturally occurring material rich in silicon. This silicon source can be used in organic agriculture, it also has a great potential of use in the acclimatization of crops. However, there are no reports of the effects of diatomaceous earth supplementation on the micropropagation of sweet potato. Thus, the objective of this study was to evaluate the effects of different concentrations of diatomaceous earth applied in vitro on the growth, physiology and anatomy of sweet potato cv. 'Brazlândia Branca' after acclimatization. Four concentrations of diatomaceous earth. After 30 days of in vitro growth, the plants were transferred to a greenhouse for acclimatization. After 45 days, leaf number, shoot and root length, fresh and dry shoot and root mass, gas exchange, chlorophyll content, root and leaf anatomy. The experimental design was completely randomized. The supplementation of diatomaceous earth in the in vitro cultivation had beneficial effects, increasing the accumulation of mass, improving the photosynthetic apparatus and promoting favorable anatomical characteristics during the acclimatization of the sweet potato plants. In addition, the use of diatomaceous earth achieved adequate seedling development, with higher seedling quality and resistance to biotic and abiotic effects than attained with control treatment.

To produce pitaya (Hylocereus spp.), it is essential that pollination occur, either artificially or by pollinating agents. This study evaluated the viability of self-pollination, cross-pollination, and natural pollination, as well as pollen viability, stigma receptivity and ideal pollination window in pitaya flowers (Hylocereus spp.). An experiment was conducted with a randomized block design consisting of four treatments: T1: manual self-pollination; T2: nocturnal open pollination; T3: diurnal open pollination; and T4: manual cross-pollination - red-fleshed pitaya [ Hylocereus polyrhizus] pollen placed on white-fleshed pitaya [ Hylocereus undatus] stigma. The experiment had four replicates, with two plants per replicate (two flowers per plant), totaling 16 flowers per treatment. The analyzed variables were fruit weight, length, diameter, titratable acidity, pH, soluble solids, and SS/TA ratio; the germination percentage of pollen grains; and the receptivity of stigmas. Artificial pollination (self- and cross-pollination) of white-fleshed pitaya (Hylocereus undatus) is viable, resulting in larger fruits than natural pollination, with cross-pollination being the most recommended. Throughout the floral opening period, the pitaya flower (Hylocereus spp.) has receptive stigma capable of receiving pollen. The flowers exhibit the highest pollen germination rate at 7 p.m, which is the ideal pollination window for pitaya.

The use of silicon in Billbergia zebrina cultivation in vitro is an alternative for optimizing micropropagation of this important ornamental plant species. The objective of the present study was to evaluate the growth and anatomical and physiological alterations in Billbergia zebrina (Herbert) Lindley plants as a function of different sources and concentrations of silicon during in vitro cultivation and acclimatization. The experimental design was completely randomized, with a double factorial arrangement and an additional control treatment (2 x 3 + 1). The first factor was relative to calcium silicate and sodium silicate added to the Murashige & Skoog culture medium; the second factor was related to its concentrations, 0.5, 1.0, and 2.0 mg L-1. After 100 days, their growth, anatomical characteristics, level of silicon and chlorophyll content were evaluated. Growth characteristics were assessed after 60 days of acclimatization period. Plants absorbed more sodium silicate than calcium silicate. This source also stressed the plants impairing their growth, but the highest silicon absorption at 1 mg L-1 attenuated the stressful conditions. The supplementation of the culture medium with calcium silicate led to improved growth, anatomical, and physiological characteristics, which benefited the development of more resistant seedlings with better performance during acclimatization.

Garlic (Allium sativum L.) plays an important role in popular culture due to its dietary and medicinal uses. It is also used to produce a wide range of pharmacologically interesting molecules. Several pathogens affect garlic plants, especially Athelia (Sclerotium) rolfsii, a fungus that is widespread and causes large economic losses. It causes direct damage to crops and leads to plant stress, which induces secondary metabolite production in plants. The use of microorganisms as biocontrol agents may induce the production of beneficial metabolites in plants that will protect it and promote resistance to pathogen attack. In addition to suppressing disease, biological control agents may have elicitor effects that could induce an increase in the production of useful bioactive secondary metabolites in plants, some of which may be of pharmacological interest. Therefore, the search for new biological control agents should also consider their potential as elicitor agents. This paper presents an analysis of the biological control of Athelia (Sclerotium) rolfsii by antagonistic microrganisms, the potential of yeasts and bacteria of the genus Bacillus for the biocontrol of phytopathogens, microrganisms influence in nutritional and bioactive compounds content of interest to the pharmaceutical industry.

The jelly palm plant [Butia capitata (Martius) Beccari] is a native palm of the Cerrado biome used for many purposes in northern Minas Gerais State, Brazil. Dormancy is common in palm seeds, resulting in slow and uneven germination that may take years to complete. Modification in the growth pattern, anatomical parameters, physiological and biochemical characteristics of the plant can be verified due to changes in the light spectrum transmitted through colored shade nets used. Therefore, the objective of this study is to evaluate the effect of colored shade nets on the leaf and root anatomy of the jelly palm plant. The experiment was performed in a completely randomized design, with five treatments, ten replicates and eight plants per replicate, totaling 400 plants. Four colored photo-converter nets with 50% shading and different radiation proportions were employed: white (985 μmol.m-2.s-1), red (327 μmol.m-2.s-1), black (433 μmol.m-2.s-1) and silver (405 μmol.m-2.s-1). The plants cultivated under direct sunlight (1000 μmol.m-2.s-1) were considered as the control group. Leaf and root anatomical analysis was performed on 10 plants per treatment. It is possible to conclude that the colored shade nets caused changes in leaf and root anatomy of the jelly palm plant (Butia capitata).

To increase the availability to consumers and add more value to persimmon (Diospyros kaki L.), which is a very perishable and seasonal fruit and in order to identify which cultivars grown in subtropical regions are more suitable for processing in the form of juice and jelly, as well as understand what the consumer profile is for these products, the objective of this study was to evaluate the influence of different persimmon cultivars (Rama Forte, Mel, Guiombo and Taubaté) grown in subtropical regions of Brazil on the physicochemical characteristics, rheological properties and sensory acceptance of the resulting juice and jelly in order to identify cultivars with the greatest potential for industrial use. The different studied persimmon cultivars had different physical and physicochemical characteristics which resulted in juices and jellies with different physicochemical, rheological and sensory characteristics. Based on sensory acceptance and productivity/adaptability of persimmon crop in Brazil, the most suitable persimmon cultivars for processing are Rama Forte and Guiombo. In this study it was found that the consumer prefers a more acidic persimmon juice and a less firm or softer, less sweet, clearer and more intense yellow color persimmon jelly.

Jatropha is a potential oilseed crop, which requires mitigating factors such as the low genetic variability of the species. The solution runs through the research of Brazilian germplasm. Attention should be given to the germplasm of jatropha the north of Minas Gerais, because this is the oldest national collection and because this region may be a regions of jatropha diversity due to selection pressure arising from environmental adversities. Therefore, the objective of this study was to investigate the genetic diversity of 48 accessions of collection from Empresa de Pesquisa Agropecuária de Minas Gerais (EPAMIG), using SSR and ISSR markers. The results showed low genetic diversity, but some individuals stood out as J. mollissima (48), J. podagrica (47), Mexican accessions (42, 43, 44 and 45) and some national accessions (28, 29, 41 and 46). Therefore, aiming to increase the genetic variability and improve the effectiveness of jatropha breeding programs, it is suggested to explore such as parental accessions to generate commercial hybrids. This fact implies the possibility to support future production of jatropha, since this culture may be an important source of income, especially for small farmers living in semiarid regions of Brazil.

In order to select phytotoxin producing rhizobacteria to control weed plants, twenty five bacterial strains previously isolated from the rhizospheres of various plants were grown in a liquid medium and, after cell removal by centrifugation, the liquid phases were freeze-dried and the products were extracted with ethyl acetate/methanol. The extracts were concentrated to dryness under vacuum and dissolved in water and sucrose solution to be submitted to in vitro assays of lettuce (Lactuca sativa L.) seed germination and wheat (Triticum aestivum L.) coleoptile growth. Although most samples affected coleoptile growth, only those from four strains reduced lettuce seed germination. Two strains of Bacillus cereus, one strain of B. pumilus and one of Stenotrophoonas altophilia were the most promising microorganisms for producing phytotoxin and, consequently, for the development of new weed control products.