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During in vitro multiplication of horticulture plant species, synthetic cytokinins such as 6-benzylaminopurine (BA) can affect the microshoot formation. Murashige and Skoog culture medium (MS) can also act as a morphogenetic response modulator. The aim was to analyze the effects of BA and a gradient of MS salts on the morphophysiological status of Billbergia zebrina microshoots. Plantlets were cultured with a gradient of MS salts (50%, 100%, 150%, or 200%) supplemented with two BA levels (0 or 13 μM). After 50 days of culture, stomatal parameters, contents of photosynthetic pigments, and chlorophyll fluorescence were assessed. Plantlets cultured in all media without BA presented a low budding rate. In contrast, plantlets cultured with BA showed 100% budding. With 13 μM BA, the leaves presented bigger stomata and wider opening. Plantlets cultured with BA had lower contents of photosynthetic pigments. MS treatments without BA supplementation did not show any change in the pigments’ ratios. Plantlets cultured with BA had lower activity of the water-splitting complex and signs of photoinhibition damage. This resulted in the reduced performance of the photosynthetic apparatus. BA exposure can ensure the inducement of adventitious microshoots. BA at the tested concentration can induce morphophysiological disorders, irrespective of MS salt concentration.

EMERGÊNCIA E DESENVOLVIMENTO DE PLÂNTULAS DE MARACUJÁ-AMARELO EM DIFERENTES SUBSTRATOS   LAÍS GERTRUDES FONTANA SILVA1; RAMON AMARO DE SALES2; FRANCIELE PEREIRA ROSSINI3; YAGO TONINI DA VITÓRIA1 E SÁVIO DA SILVA BERILLI1   1Instituto Federal do Espirito Santo – Campus Itapina, BR 259, KM 70, Colatina-ES, Brasil, laiisfontana@gmail.com; yago.agro@hotmail.com; berilli@gmail.com 2Departamento de Fitotecnia, Universidade Federal de Viçosa, Avenida Peter Henry Rolfs, s/n, Campus Universitário, CEP: 36570 900, Viçosa - MG, Brasil, ramonamarodesales@hotmail.com 3Departamento de Cultura de Tecidos, UFES – campus São Mateus, Rodovia Governador Mário Covas, Km 60, Bairro Litorâneo, 29932-540, São Mateus - ES, Brasil, francielypr@gmail.com   RESUMO: O Brasil domina a produção do maracujazeiro-amarelo, abastecendo o mercado nacional e internacional com a sua fruta e polpa. Dentro da cadeia produtiva do maracujá, na etapa de produção de mudas, um fator importante que deve ser levado em consideração é o uso da matéria orgânica na composição dos substratos, devido as diversas características benéficas que o mesmo condiciona as mudas. Nesse sentido, o presente trabalho teve o objetivo avaliar a emergência e o desenvolvimento de mudas de Passiflora edulis f. flavicarpa cultivadas em substratos com diferentes fontes de matéria orgânica. O experimento foi conduzido em casa de vegetação, em delineamento de blocos casualizados, com seis repetições e seis tratamentos, contendo cinco fontes de matéria orgânica para a composição do substrato: lodo de curtume, resíduo de torrefação de café, esterco bovino curtido, resíduo de laticínio e composto urbano, além dos tratamentos sem uso de matéria orgânica (solo com e sem adubação). Foram avaliadas características de emergência e desenvolvimento das mudas, observando-se que houve maior índice de velocidade de emergência no tratamento com resíduo de torrefação de café, além de que todos os tratamentos com fontes orgânicas apresentaram respostas satisfatórias favorecendo o desenvolvimento vegetativo do maracujá-amarelo sendo recomendadas para a produção de mudas.   Palavras-chaves: Passiflora edulis f. flavicarpa, Resíduos orgânicos, Sustentabilidade   YELLOW PASSION FRUIT PLANTLETS EMERGENCY AND DEVELOPMENT IN DIFFERENT SUBSTRATES   ABSTRACT: Brazil dominates yellow passion fruit production, supplying national and international market. In the stage of seedling production  an important factor that must be taken into account is the use of organic matter in substrates composition, due to several beneficial characteristics it brings to plantlest development. The aim of this study was to evaluate the emergence and development of Passiflora edulis f. flavicarpa grown on different substrates with organic matter sources. The experiment was conducted in a greenhouse, in randomized block design, with six treatments and (tannery sludge, coffee roasting residue, tanned bovine manure, dairy and urban compost and the control - soil with and without fertilization) six replicates,. It was evaluated the emergence and emergence characteristics of the seedlings. The results showed that there was a higher rate of emergence speed in the treatment with coffee roasting residue, besides that all treatments with organic sources presented satisfactory responses favored the yellow passion fruit vegetative development being recommended for plantlets production.   Keywords: Passiflora edulis f. flavicarpa, Organic waste, Sustainability

Despite having the ability to bioaccumulate trace elements such as cadmium (Cd), many species also present morphophysiological disorders that can hamper their use as phytoremediation plants. Since it can lead to alterations in biomass accumulation. The employment of elements that mitigate stress, such as silicon (Si), can diminish the deleterious effects caused by trace elements. The objective of this study was to analyze the anatomical and physiological modulations induced by the synergy between Cd and Si in Alternanthera tenella plants, as well as to elucidate whether Si can mitigate the harmful effects caused by Cd under in vitro conditions. Nodal segments were cultured in media containing a concentration gradient of Cd (0, 50, 100, or 200 μM) combined with two levels of Si (0 or 40 μM) for a total of eight treatments. After 34 days, the plants' anatomy, physiology, and tolerance index were analyzed. The plants presented anatomical adjustments (such as lower stomatal index and number of vessel elements), suggesting lower translocation of Cd to the aerial part. When cultured with 200 μM Cd, the plants presented the lowest Chl a/b ratio. In the presence of Si, the decline of this ratio was smaller. Plants exposed to Cd concentrations of 50 μM without Si presented a signi cant decrease in the performance of the photosynthetic apparatus and tolerance index. The presence of Si in the medium reduced the damages caused by cadmium to the plants' physiology, resulting in greater growth and higher tolerance to this element.

The use of plants that present clear physiological responses to heavy metals such as cadmium (Cd) can assist in environmental monitoring. The aim was to evaluate physiological responses of Cd in Alternanthera tenella plants in micro-controlled conditions and to assess the its tolerance level and bioindicator potential. Nodal segments of A. tenella were grown in flasks containing semi-solid MS medium supplemented with (0, 50, 100, and 150 μM Cd). The total fresh and dry weight of the plants, in addition to physiological analyses, were determined after 30 days of cultivation. Plants submitted to Cd showed a reduction in biomass and photosynthetic pigments content. The decline in the Chl a/b ratio indicated the deleterious effects of Cd, as evidenced by the decrease in the density of active reaction centers (RC/CSM). The levels of deterioration in the functionality or structural integrity of the thylakoid membranes (WL) and the activity of the oxygen evolution complex (WK) increased as a function of Cd concentrations. The decreases in photochemical and non-photochemical quenching (qP and qN, respectively) observed in plants exposed to Cd indicated photochemical dysfunctions. Additionally, the increase in the quantum yield of non-regulated energy dissipation (ΦNO) indicated the presence of photodamage. Plants had a low/intermediate TI level (≥21.7) in the analyzed concentration range. A. tenella plants can bioaccumulate high amounts of Cd. The level of physiological responses of A. tenella is dependent on the concentration of Cd, which makes the use of this species even more promising as a bioindicator for this metal.

Despite having the ability to bioaccumulate trace elements such as cadmium (Cd), many species also present morphophysiological disorders that can hamper their use as phytoremediation plants. Since it can lead to alterations in biomass accumulation. The employment of elements that mitigate stress, such as silicon (Si), can diminish the deleterious effects caused by trace elements. The objective of this study was to analyze the anatomical and physiological modulations induced by the synergy between Cd and Si in Alternanthera tenella plants, as well as to elucidate whether Si can mitigate the harmful effects caused by Cd under in vitro conditions. Nodal segments were cultured in media containing a concentration gradient of Cd (0, 50, 100, or 200 μM) combined with two levels of Si (0 or 40 μM) for a total of eight treatments. After 34 days, the plants' anatomy, physiology, and tolerance index were analyzed. The plants presented anatomical adjustments (such as lower stomatal index and number of vessel elements), suggesting lower translocation of Cd to the aerial part. When cultured with 200 μM Cd, the plants presented the lowest Chl a/b ratio. In the presence of Si, the decline of this ratio was smaller. Plants exposed to Cd concentrations of 50 μM without Si presented a significant decrease in the performance of the photosynthetic apparatus and tolerance index. The presence of Si in the medium reduced the damages caused by cadmium to the plants' physiology, resulting in greater growth and higher tolerance to this element.