Fenologia e desempenho ecofisiológico de Vasconcellea quercifolia A.St.-Hill
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2020-07-17
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Universidade Estadual Paulista (Unesp)
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A espécie Vasconcellea quercifolia A.St.-Hill. apresenta grande importância ecológica, assim como importantes características fisiológicas de interesse ao melhoramento genético, como tolerância a baixas temperaturas e resistências a doenças que afetam o desenvolvimento de culturas da mesma família. Com isso, esta pesquisa teve o objetivo de avaliar o desempenho fenológico, reprodutivo e ecofisiológico da espécie, em sua população natural. O estudo foi desenvolvido na Fazenda Lageado, da Faculdade de Ciências Agronômicas e no Departamento de Botânica do Instituto de Biociências da UNESP – campus Botucatu – SP. Pelas visitas quinzenais observou-se alta sincronia e correlação entre os fenômenos avaliados, destacando a grande influência da radiação e temperatura para todas as fases (Capítulo I). A brotação tem início em setembro e se estende até dezembro, com pico em outubro. A floração iniciou-se em setembro, se estendendo até o mês de fevereiro, sendo que o pico da floração ocorre entre novembro e dezembro. A frutificação iniciou-se em outubro e teve pico entre dezembro e fevereiro e os últimos frutos foram observados em maio. A queda foliar inicia-se em dezembro perdendo 100% das folhas até o início do mês de junho e entra em repouso vegetativo até o final de agosto. No capítulo II são descritos o efeito de diferentes concentrações de ácido giberélico (GA3) na germinação de sementes em câmara Biochemical Oxygen Demand (BOD) e na emergência de plântulas em casa de vegetação. Para o teste de germinação em BOD, a maior concentração de GA3 (500 mg L-1) proporcionou 69,5% de germinação. Para a emergência de plântulas, GA3 à 300 mg L-1 (T4) foi mais eficiente quanto ao índice de Velocidade de Emergência (IVE), proporcionando emergência de plântulas mais rápida e mais uniforme em relação aos demais tratamentos, promovendo também maior acúmulo de massa da parte aérea das plântulas, assim como das raízes. A espécie é considerada de alto poder germinativo, distribuído em longos períodos e bastante desuniforme. O capítulo III foi escrito a partir do comportamento da planta em relação às trocas gasosas e presença e atividade de enzimas antioxidantes, de acordo com a presença dos eventos fenológicos da espécie. As coletas foram realizadas a cada fenofase. As plantas apresentaram menor taxa de assimilação de CO2 nas fenofases frutificação e queda foliar. As enzimas superóxido dismutase (SOD) e catalase (CAT) apresentaram maior atividade no período da brotação, resultando na menor concentração de H2O2 nesta fase. A peroxidação lipídica aumentou a cada fenofase, registrando maior teor no período em que as plantas já se encontravam em uma escala avançada de queda foliar. As frequentes e distintas condições ambientais determinaram alterações nos mecanismos fisiológicos das plantas, causando reações no aparato fotossintético, assim como, no sistema antioxidante.
The species Vasconcellea A.St.-Hill. it presents great ecological importance, as well as important physiological characteristics of interest to genetic improvement, such as tolerance to low temperatures and resistance to diseases that affect the development of cultures of the same family. Thus, this research aimed to evaluate the phenological, reproductive and ecophysiological behavior of the species, in its natural population. The study was carried out at Farm Lageado, Faculty of Agronomic Sciences and Department of Botany, Biosciences Institute, UNESP - Botucatu campus - SP. In Chapter I, through biweekly visits, there was a high synchrony and correlation between the variable evaluated, highlighting the great influence of radiation and temperature for all phases. Sprouting begins in September and extends to December with a peak in October. Flowering started in September, extending until February, with peak flowering occurring between November and December. Fruiting started in October, peaked between December and February and the last fruits were seen in May. The leaf fall starts in December, losing 100% of the leaves until the beginning of June and enters vegetative rest until the end of August. In Chapter II, the effect of different concentrations of gibberellic acid (GA3) on germination in Biochemical Oxygen Demand (BOD) and seedling emergence in the greenhouse of Vasconcellea quercifolia A.St.-Hill was evaluated. For the BOD germination test, the highest concentration (500 mg L-1) provided 69.5% of germination. For seedling emergence, the concentrations of the regulator did not differ, however 300 mg L-1 (T4) was more efficient in terms of the Emergency Speed Index (IVE), providing faster and more uniform seedling emergence in relation to the others. Treatments, also promoting greater accumulation of mass in the aerial part of the seedlings, as well as the roots. The species is considered to have high germinative power, distributed over long periods and quite uneven. Chapter III was written from the behavior of the plant in relation to gas exchange and the presence of antioxidant enzymes, according to the presence of the phenological events of the species. Collections were made at each phenophase. Plants showed a lower rate of CO2 assimilation in fruiting and leaf fall phenophases. SOD and CAT had greater activity in sprouting, resulting in the lowest concentration of H2O2 in this phase. Lipid peroxidation increased with each phenophase, registering a higher content in the period when the plants were already in an advanced scale of leaf fall. The frequent and distinct environmental conditions determined changes in the physiological mechanisms of the plants, causing reactions in the photosynthetic apparatus, as well as in the antioxidant system.
The species Vasconcellea A.St.-Hill. it presents great ecological importance, as well as important physiological characteristics of interest to genetic improvement, such as tolerance to low temperatures and resistance to diseases that affect the development of cultures of the same family. Thus, this research aimed to evaluate the phenological, reproductive and ecophysiological behavior of the species, in its natural population. The study was carried out at Farm Lageado, Faculty of Agronomic Sciences and Department of Botany, Biosciences Institute, UNESP - Botucatu campus - SP. In Chapter I, through biweekly visits, there was a high synchrony and correlation between the variable evaluated, highlighting the great influence of radiation and temperature for all phases. Sprouting begins in September and extends to December with a peak in October. Flowering started in September, extending until February, with peak flowering occurring between November and December. Fruiting started in October, peaked between December and February and the last fruits were seen in May. The leaf fall starts in December, losing 100% of the leaves until the beginning of June and enters vegetative rest until the end of August. In Chapter II, the effect of different concentrations of gibberellic acid (GA3) on germination in Biochemical Oxygen Demand (BOD) and seedling emergence in the greenhouse of Vasconcellea quercifolia A.St.-Hill was evaluated. For the BOD germination test, the highest concentration (500 mg L-1) provided 69.5% of germination. For seedling emergence, the concentrations of the regulator did not differ, however 300 mg L-1 (T4) was more efficient in terms of the Emergency Speed Index (IVE), providing faster and more uniform seedling emergence in relation to the others. Treatments, also promoting greater accumulation of mass in the aerial part of the seedlings, as well as the roots. The species is considered to have high germinative power, distributed over long periods and quite uneven. Chapter III was written from the behavior of the plant in relation to gas exchange and the presence of antioxidant enzymes, according to the presence of the phenological events of the species. Collections were made at each phenophase. Plants showed a lower rate of CO2 assimilation in fruiting and leaf fall phenophases. SOD and CAT had greater activity in sprouting, resulting in the lowest concentration of H2O2 in this phase. Lipid peroxidation increased with each phenophase, registering a higher content in the period when the plants were already in an advanced scale of leaf fall. The frequent and distinct environmental conditions determined changes in the physiological mechanisms of the plants, causing reactions in the photosynthetic apparatus, as well as in the antioxidant system.
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Evento fenológico, Germinação, Trocas gasosas, Bioquímica, Phenological event, Germination, Gas exchange, Biochemistry