Salt stress is one of several major abiotic stresses that affect plant growth and development, and there are many evidences that silicon can ameliorate the injuries caused by high salinity. This study presents the results of an assay concerning: (1) the effect of in vitro NaCl-induced salt stress in cape gooseberry plants and (2) the possible mitigating effect of silicon in saline conditions. For that, nodal segments were inoculated in Murashige and Skoog (MS) medium under salinity (0.5 and 1.0% NaCl) with different silicic acid concentrations (0, 0.5 and 1.0g L-1). Phytotechnical characteristics, photosynthetic pigments content, and leaf anatomy were evaluated after 30 days. Shoot length, root length, number of leaves and buds, fresh and dry weight, pigment content, stomatal density and leaf blade thickness were drastically reduced by increased salt level. The supply of silicon (1.0g L-1) has successfully mitigated the effect of salinity at 0.5% NaCl for chlorophyll, carotenoids, stomatal density and leaf blade thickness. When salt stress was about 1.0%, Si was not effective anymore. In conclusion, we affirmed that, in in vitro conditions, salt stress is harmful for cape gooseberry plants and the addition of silicon showed effective in mitigating the saline effects of some features.
The objective of the present study was to evaluate the interference of water excess in soil on the growth of young coffee plants of the Mundo Novo and Catuaí cultivars.Plants were subjected to the following three different substrate water availability conditions: control (wellwatered), continuous substrate waterlogged, and intermittent substrate waterlogged. Several growthrelated traits were evaluated over the course of 19 weeks. Based on the number and quality of the affected variables from all forms of analyses, the Catuaí cultivar showed greater sensitivity to waterlogging. Both cultivars exhibited growth inhibition in response to substrate waterlogging stress, which was exacerbated by premature leaf dropping.Efeitos do excesso de água no crescimento de mudas de cafeeiro (Coffea arabica L.) RESUMO. O presente trabalho visou avaliar a interferência do excesso hídrico do solo sobre o crescimento de plantas jovens de café, cultivares Mundo Novo e Catuaí. As mudas foram submetidas a três condições de disponibilidade de água no substrato: controle (mudas irrigadas), encharcamento contínuo do substrato e encharcamento intermitente do substrato. Diversas características de crescimento foram analisadas ao longo de 19 semanas. Baseado no número e qualidade das variáveis afetadas em todas as análises, a cultivar Catuaí mostrou maior sensibilidade ao encharcamento.. Ambas as cultivares de café apresentaram inibição do crescimento em resposta ao estresse por encharcamento do substrato, que foi agravado pela queda prematura das folhas.Palavras-chave: encharcamento do solo, hipoxia, cultivar mundo novo, cultivar catuaí.
The objective of this work was to evaluate the productivity and beverage sensory quality of arabica coffee under the influence of tree species cultivated at different spacings. The experiment was set in 2012, in the municipality of Santo Antônio do Amparo, in the state of Minas Gerais, Brazil. A randomized complete block design was carried out with four replicates and seven treatments, as follows: Catuaí Vermelho IAC 99 Coffea arabica in monoculture (3.40x0.65 m); and this cultivar intercropped at two spacings (9.0x13.6 and 18.0x13.6 m) in the coffee row ‒ either with African mahogany (Khaya ivorensis), teak (Tectona grandis), or pink cedar (Acrocarpus fraxinifolius). Three coffee rows were fixed between rows, totaling 13.6 m between the wooded rows. Productivity, sensory analysis (cup test), and content analysis of sensory attributes were evaluated in the 2017 and 2018 crop years. The treatments and years of harvest influenced productivity. The sensory analysis was positive for coffee intercropped with African mahogany and teak, in 2018. Sensory attributes and nuances are modified by the years of harvest. Arabica coffee plants intercropped with African mahogany show a superior productivity, regardless of the spacing between species, as well as a higher sensory quality in the 2018 harvest.
Climate change greatly influences coffee production, especially in areas infested with plant‐parasitic nematodes. In this study, coffee genotypes showed differences in their morphological and physiological characteristics when subjected to a water deficit and parasitism by Meloidogyne paranaensis. The cultivar IPR 100 had the largest superficial and volumetric root system area, even when parasitized. The two progenies (MG 0179‐1 and MG 0179‐3) and the cultivar Catuaí IAC 62 had a similar surface area (p < .05) when parasitized. However, the root surface area and volume of MG 0179‐3 increased by 96% and 400%, respectively, when parasitized by M. paranaensis. On the other hand, Catuaí IAC 62 had a 31% reduction in root surface area. Catuai 62 and IPR 100 showed higher sensitivity to drought when parasitized because of the increased photochemical sensitivity and reduction in photochemical quenching. In MG 0179‐1 and MG 0179‐3, an increase in non‐photochemical quenching occurred in response to stress, indicating that these progenies use a photochemical response to protect photosystem II. In this work, MG 0179‐3, which is resistant to M. paranaensis, was remarkable because, interestingly, the infestation caused an increase in its root surface area. In addition, MG 0179‐3 had relatively good photochemical performance under water deficit and M. paranaensis parasitism.
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