Productivity of lettuce in greenhouse as affected by humic and fulvic acids application in association to mineral fertilizer

ABSTRACT Humic substances (HS) have proved to be effective in improving the productivity of vegetable crops. We examined the effect of commercial biostimulants rich in humic (HA) and fulvic acids (FA) obtained from leonardite on agronomic efficiency and nutrient content in the leaves of lettuce (Lactuca sativa). A greenhouse experiment was carried out employing 2.5-L pots containing Ultisol samples that were supplied with commercial biostimulants rich in HA and FA, alone and in combination with NPK mineral fertilizer. The application of HS biostimulants associated to mineral fertilization to the lettuce plants provided the greatest values of the studied variables, namely: plant height and diameter, leaf number per plant and root length. The combination of FA biostimulants and mineral fertilization increased the lettuce productivity relative to the inorganic fertilizer alone. The combined application of rich biostimulants FA and HA with NPK fertilizes influenced K and Fe uptake by the plants, and their accumulation in the aerial portion. Our results suggest that HS products potentialize the nutritional effect of the mineral fertilizer, when applied in combination.

Productivity and growth in cowpea inoculated with rhizobia under different light environments

The objective of this work was to verify the influence of light environments combined with rhizobia inoculation on cowpea growth and productivity. A completely random design was used in a 4x4 factorial scheme, with four light environments, four nitrogen sources and eight replicates in split plot parcels. Light environments were set by means of photo-conversion and thermo-conversion nettings (Aluminet®, red net and black net) and control treatment without shading (full sun). Nitrogen sources were constituted by the strains INPA 03-11B - SEMIA 6462 (Bradyrhizobium elkanni) and UFLA 03-84 - SEMIA 6461 (Bradyrhizobium viridifuturi), and two control treatments: with 70 kg ha-1 of mineral nitrogen and without N. Plant height, indices of chlorophyll a, b and total chlorophill, the number of leaves, number of nodules, dry matter of nodules, dry matter of the aerial portion, dry matter of roots and total dry matter, relative efficiency, gathering of nitrogen in the aerial portion, number, length and matter of pods per plant and dry matter of 100 grains, were evaluated. . There was interaction between light conditions and nitrogen sources for the number of nodules. Individual effect was observed in all other variables. Strain INPA 03-11B was able to promote higher nodulation in cowpea plants in light environments under full sun and Aluminet and the strain UFLA 03-84 only under full sun conditions. However, the efficiency of diazotrophic bacteria to promote vegetative growth, nitrogen gathering and production was not influenced by different light environments. Thus, full sun cultivation is recommended, independently of the nitrogen source used.

IN VITRO SEED GERMINATION AND PLANT GROWTH OF “CABEÇA-DE-FRADE” (CACTACEAE)

ABSTRACT The genus Melocactus (“cabeça-de-frade”) comprises 32 species in Brazil, of which M. glaucescens and M. paucispinus are threatened with extinction. The present work evaluated the effects of different concentrations of Murashige & Skoog (MS, MS/2 and MS/4) culture medium and sucrose (15 g L-1 and 30 g L-1) on in vitro seed germination and plant growth of M. glaucescens and the efficiency of sterilization with sodium hypochlorite (NaOCl) on in vitro seed germination and plant growth of M. glaucescens when using seeds and M. glaucescens and M. paucispinus when using apical segment of cladode. In M. glaucescens, the final germination at the different MS and sucrose concentrations varied between 53.5 and 68.1% and the best results for in vitro growth were observed with the lowest mineral salt (MS/2 and MS/4) and sucrose (15 g L-1) concentrations, with lengths of the aerial portion of 9.70 and 10.76 mm, respectively. There was no difference in seed germination and plant growth in chemical and autoclave medium. It is concluded that the use of chemical sterilization with NaOCl at low concentrations of salts (MS/2 and MS/4) and sucrose (15 g L-1) are quite advantageous for producing ornamental plants germinated in vitro and/or apical segment of cladode of M. glaucescens andM. paucispinus, representing a reduction of costs for in vitro cultivation of this species.

Isolation and structure elucidation of a new oleanane type glycoside from the aerial portion of Cestrum nocturnum

Cestrum nocturnum (Solanaceae) is an ornamental plant cultivated in various parts of the world due to its sweet-scented white flowers. It is commonly called night-blooming Jessamine (Raat ki Rani). The genus is known for its toxicity to feedents. The leaves may cause uneasiness in animals which may lead to severe gastroenteritis. The plant is known to be a rich source of pharmacologically active saponins. Looking to its various pharmacological activities as reported, the plant was explored for the isolation of new phytochemicals. During the process, a new oleanen type glycoside was isolated from the butanolic fraction of the leaves of Cestrum nocturnum and was characterized as 3-O-β-D-xylopyranoside-olean-12-en-28-oic acid-28-O-β-arabinopyranosyl-(1-3)-β-D-galacto-pyranosyl-(1-2)-β-D-glucopyranosyl-(1-4)-β-D-glucopyranosyl ester, along with two reported compounds nocturnoside A and karativoside A. The structure was elucidated on the basis of 1D and 2D NMR and mass spectrometry. Bull. Chem. Soc. Ethiop. 2020, 34(1), 141-148. DOI: https://dx.doi.org/10.4314/bcse.v34i1.13

Inoculation of diazotrophic bacteria in chicory

ABSTRACT Inoculating crops with diazotrophic bacteria constitutes a feasible biotechnological tool to reduce or even avoid the use of nitrogen fertilizers and to improve the nutritional status of crops. However, the potential use of such technology is limited due to the lack of studies in diverse vegetable crops. We evaluated the production of chicory (Cichorium intybus) in response to inoculation with diazotrophic bacteria in two soil classes. The experiments were performed under greenhouse conditions and under a completely randomized design. The treatments were constituted by strains UFRB FA34C2-2, UFLA 03-84 and INPA 0311B, and two control treatments (devoid of bacterial inoculation and with and without nitrogen fertilization). Two experiments were carried out, one using a soil classified as a dystrophic yellow Latosol (Oxisoil) and one using a Quartsandy Neosol (Typic Quartzipsamment). Chlorophylls a, b and total; plant height; number of leaves; dry mass of the aerial portion; dry mass of roots; total dry mass; effectiveness; efficiency in addition to N and P gathering in the aerial portion, were evaluated 60 days after seeding. The inoculation with diazotrophic bacteria resulted in adequate production when compared to the control treatment without nitrogen fertilization and without inoculation. Diazotrophic bacteria showed potential supplying nitrogen to chicory plants and spare the use of nitrogen fertilization in both soil classes. The strain INPA 0311B, recommended for cowpea, promoted vegetal growth and increased the dry weight of the aerial portion in chicory, under both dystrophic yellow Latosol (Oxisoil) and Neossolo Quartzarênico (Typic Quartzipsamment), when cultivated under greenhouse conditions.

ELECTRICAL CONDUCTIVITY AND QUALITY OF DIFFERENT UMBEL ORDER CARROT SEEDS

Carrot seeds exhibit irregular vigor due to the wide blooming period of the crop. Results from germination tests are insufficient to evaluate the physiological potential. Thus, vigor tests are used in combination with germination tests. The objective of this work was to evaluate the quality of carrot seeds from different umbel order and the electrical conductivity under different temperatures and imbibing periods. Carrot seeds from cultivar Brasilia were used to perform the experiments. Content of water, the first and the final score of the germination test, index of germination rate, and length of roots and of the aerial portion were determined in the initial characterization. The electrical conductivity test was completed with replicates containing 50 seeds, in 25 mL deionized water at 20, 25 and 30oC. Evaluations were performed with 2, 4, 6, 8, 12 and 24 hours of imbibing period. The experiment was accomplished under a completely random statistical design. The quality of carrot seeds varied according to the umbel order. Seeds of secondary umbels showed better physiological quality. The electrical conductivity test is efficient to evaluate the vigor of carrot seeds with 8 hours of imbibing period at 25°C.

Quality of Myracrodruon urundeuva seedlings in different container sizes and organic compost proportion

Myracrodruon urundeuva, commonly known as black aroeira is a species regularly found in diverse Brazilian biomes, especially in the Caatinga. The species is a timber tree with great quality wood used extensively to construct buildings. The species has chemical components which confer high resistance and protection against pests, thus being used to prepare insecticides as well as cosmetics. Due to its diverse utilization and predatory exploration, the species has become an endangered species. Thus, the objective of this work was to evaluate the influence of organic compost and the size of the containers in the development of M. urundeuva seedlings. The experiment was performed in greenhouse in a factorial scheme 5 x 3, represented by 5 proportions of organic compost: soil (80, 60, 40, 20 and 0% of compost) and 3 container sizes (20x30, 18x22 and 12x18 cm), under a completely randomized statistical design with 5 replicates. The variables evaluated were: neck diameter; seedling height; number of leaves; length of the roots; dry weight of leaves; dry weight of stems; dry weight of the aerial portion; dry weight of roots; height/diameter ratio and Dickson’s quality index. There was significant interaction between treatments for all variables evaluated. When analyzing the containers individually or interacting with compost proportion, the container with volume of 1.335 dm³ was the most adequate for production of aroeira seedlings. Concerning compost proportion alone, the proportion of 40% proportioned the best results for all the evaluated parameters.

GROWTH RESPONSE OF Bauhinia Variegata L. TO INOCULATION AND ORGANIC FERTILIZATION

ABSTRACT The objective of this work was to evaluate the initial growth of Bauhinia variegata L. when inoculated and fertilized with different proportions of organic compost. The experiment was performed in greenhouse in a completely random factorial (2 x 5) + 1 design, with 9 replicates, constituted by the presence or absence of inoculation, five proportions of organic compost:soil (0:100, 20:40, 40:60, 60:40 and 80:20; v/v) and one additional treatment with chemical fertilization without inoculation. Ninety days after sowing, the plant height, stem diameter, number of leaves, radicular length, dry mass of the aerial portion, dry mass of roots, total dry mass, Dicksosn's quality index (IQD), contents of nitrogen and carbon and the C/N ratio of the dry mass of the aerial portion, were evaluated. The inoculation with diazotrophic bacteria stimulated growth in height, stem height/diameter ratio, dry mass of the aerial portion, dry mass of roots, total dry mass and the foliar contents of nitrogen and carbon in seedlings of B. variegata L. Seedlings grown using organic compost showed better development when compared to seedlings grown only in soil with or without chemical fertilization. Seedlings grown with formulated substrate at a proportion of 16:84 (organic compost:soil + inoculation) exhibited higher IQD, therefore, this constitutes the recommended proportion for production of B.variegata L. seedlings.