The time when the seed germinates is very important. Ability to change the time of germination may be very advantageous. It allows the emerging seed to choose the best time according to abiotic conditions, and also to avoid of competition with neighbouring individuals. The seed reacts not only on adult plants and seedlings, but also on other seeds, with which is able to communicate. For a better understanding to this mechanism I conducted an experimental study with twenty-six species. The species were selected according to their position in long succession seres of mesic/xeric abandoned fields in Český kras. The seeds were left to germinate in pairs in all combinations among them. Here I present the results where I show how the time of emergence changes, depending on presence of neighbouring seed. Also, I show how these changes in germination are related to species specific traits. Out of this, I tried to influence communication between seeds by adding activated carbon. Activated carbon should stop the communication by highly absorbing surface. The time of germination of seeds which germinated alone was not proportional to the time of germination of seeds which germinated with neighbours. This correlation showed up like nonlinear, late-emerging seeds emerging unproportionally later when emerging...

Made available in DSpace on 2016-12-23T14:37:37Z (GMT). No. of bitstreams: 1 Fabiola Lacerda de Souza Barros.pdf: 6472406 bytes, checksum: d8013423c68ed8608b3a5668f18e35ac (MD5) Previous issue date: 2008-07-10 / Foram realizados experimentos in vivo e in vitro objetivando a propagação assexuada do mamoeiro (Carica papaya L.). O experimento in vivo foi realizado com a cultivar Golden , do grupo Solo , em lavoura comercial com dois anos e meio de idade em final de produção, onde se estudou o efeito da poda em diferentes alturas do tronco (inteira sem o ápice, 0,5, 1,0, 1,5, 2,0 m) a partir do solo, para se identificar qual destas proporcionaria maior rendimento de brotações laterais aptas à estaquia. Uma contagem de brotações aos 25 dias após a poda a diferentes alturas foi realizada no experimento in vivo. As brotações contabilizadas foram podadas e, posteriormente, feita outra contagem de novas brotações aos 50 dias. Com a poda a 2,0 metros de altura, obteve-se maior número de brotações aos 25 e aos 50 dias, no período do verão, mostrando viabilidade no reaproveitamento de lavouras em final de produção na propagação assexuada. Meios de enraizamento foram testados nos experimentos in vitro. No primeiro experimento foram estudadas as concentrações do meio MS a 100%, 50% da força e MS modificado associados aos níveis do regulador de crescimento AIB (0; 0,1; 0,2; 0,4 e 0,8 mg L-1). No primeiro experimento o enraizamento foi insatisfatório devido à contaminação bacteriana, aliada a uma possível fitotoxidez do antibiótico utilizado (cefotaxima 100 mg L-1), ou ainda, ao acúmulo de citocinina remanescente da fase de multiplicação, prejudicando as reações morfogênicas e o enraizamento. No segundo experimento, utilizou-se meio de enraizamento contendo ou não carvão ativo, na concentração 1gL-1, associado aos níveis do regulador de crescimento ANA (0; 0,25; 0,5; 1,0; 2,0 mgL-1). Também não se obteve sucesso no enraizamento, provavelmente pela quantidade ou associação dos antibióticos utilizados (rifampicina 300 mg L-1 +cloranfenicol 100 mg L-1) ao meio de cultura, mesmo tendo controlado acontaminação bacteriana. O carvão ativo a 1 g L-1 acrescentado ao meio, apesar de não auxiliar o enraizamento, mostra significância de forma isolada, sendo benéfico ao desenvolvimento da parte aérea e impedindo o calejamento na base dos ramos, mostrando eficiência na adsorção de substâncias tóxicas do meio de cultivo, em relação ao tratamento que não recebeu o carvão ativo / The experiments were carried out in vivo and in vitro having of the objective the assexual reproduction of the papaya tree (Carica papaya L.). The experiment in vivo was accomplished with to cultivate Golden, of the group Sole, in commercial farming with two and a half years of age in production end, where it was studied the effect of the pruning in different heights of the trunk (it completes without the apex, 0,5, 1,0, 1,5, 2,0 m) starting from the ground, and to identify which of these it would provide larger income of capable production of lateral shoots to the cutting. With the pruning to 2,0 meters of height was obtained larger shoots number, in two consecutive pruning, in other words, to the 25 and 50 days, in the period of the summer, showing viability in the recycling of farmings in production end in the assexual reproduction. In the experiments in vitro were tested rooting medium. In the first experiment were studied the concentrations of the MS medium of 100%, 50% of the force and MS modified associates at the levels of the growth regulator AIB (0; 0,1; 0,2; 0,4 and 0,8 mg L-1). The rooting was unsatisfactory due to the bacterial contamination, allied to a possible phytotoxity of the used antibiotic (cephotaxin 100 mg L-1), or still, to the kitocinin accumulation remaining of the multiplication phase harming the morphogenics reactions and the rooting. In the second experiment was used rooting medium containing (1 g L-1) or not active coal, associate at the levels of the growth regulator ANA (0; 0,25; 0,5; 1,0 and 2,0 mg L-1). It was not also obtained success in the rooting probably for the amount or association of the antibiotics used (Rifampicin 300 mg L-1 + cloranphenicol 100 mg L-1) in the culture medium, even having controlled the bacterial contamination. The active coal to 1 g L-1 increased to the medium, in spite of not aiding the rooting show significance in an isolated way, being beneficial to the development of the aerial part and impeding the calluse in the base of the shoots, showing efficiency in the adsorption of poisonous substances of the culture medium, in relation to the treatment that didnt receive the active coal