Effects of moisture content and temperature during storage on germination of the achenes of Bidens gardneri Baker

Abstract

-(Effects of moisture content and temperature during storage on germination of the achenes of Bidens gardneri Baker). Bidens gardneri is a herbaceous species of the cerrados, whose seeds are light sensitive at 25°C, but they become indifferent to light when stored in soil. In this work the effects of moisture content, temperature and light (during storage) upon light sensitivity during germination were studied. Ripe achenes were collected in the cerrados of Itirapina and Moji Guaçu, State of São Paulo, Brazil. The storage conditions of the achenes varied in each experiment. Achenes were stored in darkness or light, in closed bottles, at 4°C, 20/30°C or 25°C. Achenes were imbibed for 24 h at 4°C, 25°C or 20/30°C (in darkness) and then stored for 1, 10, 20, 30 and 40 days (40 days only for 4°C and 25°C). Germination tests were conducted at 25°C and 20/30°C. The achenes not previously imbibed showed sensitivity to light during germination. High moisture content did not affect light sensitivity of the achenes during germination but high moisture content together with storage temperatures of 25°C and 20/30°C had a deleterious effect upon the longevity of the achenes. Alternate temperatures during germination did not change the light sensitivity of newly collected achenes from Itirapina but changed the light sensitivity of the achenes stored imbibed at 4°C in darkness. Alternate temperatures during storage of achenes with low moisture content did not change their photoblastism when germination was carried out at 25°C. Alternate temperatures during storage of achenes with high moisture content followed by alternate temperatures during germination changed the light sensitivity of the achenes.RESUMO -(Efeito do conteúdo de água e temperatura durante o armazenamento na germinação dos aquênios de Bidens gardneri Baker). Bidens gardneri é uma espécie herbácea dos cerrados, cujas sementes são fotoblásticas positivas a 25°C, mas tornam-se indiferentes à luz quando armazenadas em solo. Neste trabalho, foram estudados os efeitos do conteúdo de água dos aquênios, da temperatura e da luz (durante o armazenamento) na sensibilidade à luz durante a germinação. Os aquênios foram coletados nos cerrados de Itirapina e de Moji Guaçu, estado de São Paulo, Brasil. As condições de armazenamento variaram em cada experimento. Os aquênios foram armazenados no escuro ou em luz, em vidros fechados a 4°C, 25°C e 20/30°C. Os aquênios foram embebidos por 24 horas a 4°C, 25°C e 20/30°C (no escuro) e então armazenados por 1, 10, 20, 30 e 40 dias (40 dias somente para 4°C e 25°C). Os testes de germinação foram conduzidos a 25°C e 20/30°C. Os aquênios que não foram embebidos apresentaram sensibilidade à luz durante a germinação. O conteúdo alto de água durante o armazenamento não afetou a resposta à luz dos aquênios durante a germinação, mas o conteúdo alto de água em temperaturas de armazenamento de 25°C e 20/30°C tiveram efeito deletério na longevidade dos mesmos. As temperaturas alternadas durante a germinação não alteraram a resposta à lu...

Seed germination in Cerrado species

“…Achenes stored for up to six months at 4°C showed light sensivity, but after nine months storage, the photoblastic response is lost for the shortest and longest achenes (Sassaki et al, 1999b). Alternate temperatures during storage of achenes with high moisture content followed by alternate temperatures during germination change the light sensitivity of the achenes (Rondon et al, 2001). According to the authors, this could explain the germination of the achenes during storage in the soil.…”

Qualitative Loss of Maize under Different Bag Storage Modes

“…It was also seen that the moisture increased initially slowly upto30 days of storage period and then it increased rapidly as relative humidity increases day-by-day. The elevation in water activity with storage period was observed which had similar trend as moisture content (Rondon et al, 2001).…”

“…In Bihar, farmers store Maize crop in homes, on the field, in the open, jute or polypropylene bags, clay structures and baskets. During storage, quantitative as well as qualitative losses occur due to insects, rodents and micro-organisms (Rondon et al, 2001;(Murdock, 2014)). …”

Capacidade de germinação de Abrus precatorius L. (Fabaceae) / Germination capacity of Abrus precatorius (Fabaceae)

“…2021 as sementes aptas a responderem às flutuações térmicas possuem mecanismos enzimáticos que funcionam a diferentes temperaturas, de maneira que a germinação é iniciada apenas quando ocorre variação térmica que dá início ao processo catalisado por essas enzimas. Em Bidens gardneri, uma herbácea ocorrente em áreas abertas e marginais de Cerrado, as temperaturas alternantes de 20 a 30ºC durante o armazenamento de aquênios com teor alto de água aumentam a germinação no escuro e, portanto, alteram a resposta fotoblástica (Rondon et al, 2001).…”