Land plants are characterized by the alternation of two generations: the haploid gametophyte and the diploid sporophyte. As land plants evolved from bryophytes to vascular plants, the sporophyte became the dominant generation in the life cycle. The sporophytes of bryophytes are developmentally simple structures characterized by determinate growth. In contrast, the sporophytes of vascular plants diverged to become highly variable and often complex structures with indeterminate growth. KNOTTED1-LIKE HOMEOBOX (KNOX) genes encode homeodomain containing transcription factors that are key regulators of sporophyte development. KNOX genes are divided into two subclasses, class 1 and class 2. The critical role of class 1 KNOX genes in the apical growth of all extant land plants studied to date, suggests that modifications to class 1 KNOX gene function may have played an important role in sporophyte evolution. However, the nature of any such modifications is largely unknown. In this study, a number of cross-species complementation experiments were carried out to determine the extent to which class 1 KNOX gene function is conserved between different land plant groups. The role of KNOX genes in hornworts was also investigated because hornworts are believed to be the sister group to vascular plants. The work presented in this thesis demonstrates that the function of class 1 KNOX genes is conserved between lycophytes and angiosperms. In contrast, the function of class 1 KNOX genes appears to have diversified between bryophytes and vascular plants. Collectively, these results indicate increased complexity of class 1 KNOX gene function during the evolution of land plants.

Orientador: Sylvio Luis Honorio / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-13T08:26:48Z (GMT). No. of bitstreams: 1 Leme_JoseMarcos_D.pdf: 2428565 bytes, checksum: 307c11c514ff806a02eefd633c29ee84 (MD5) Previous issue date: 2009 / Resumo: A demanda mundial pela excelência dos produtos da floricultura requer a prática do uso de tecnologias adequadas para melhor retenção da qualidade, entre elas, um fator muito importante é a aquisição de material vegetativo selecionado, livre de contaminações e garantido por laboratórios especializados. Visando avaliar a qualidade de clones da principal variedade brasileira de antúrio, foi desenvolvido este trabalho com objetivos de determinar os principais indicadores de qualidade pré-colheita e pós-colheita no desenvolvimento de plantas e flores, respectivamente, oriundas de cultura de tecidos. Foram utilizados Anthurium andraeanum Lind. ('IAC Eidibel') cultivados em sistema hidropônico fechado e substrato de fibra de coco, com plantas e flores analisadas quali-quantitativamente. Como resultados, o antúrio 'IAC Eidibel' apresentou: plena adaptação e desenvolvimento no cultivo em sistema hidropônico fechado com substrato de fibra de coco; precocidade na produção de flores de corte; crescimento médio das plantas, em termos de altura, constante e homogêneo; produção média de uma folha/planta/mês; incremento médio de massa de matéria seca nas folhas maior que o aumento de área foliar, ambos constantes; maior acúmulo de massa de matéria seca de espata no ponto de maturação de 1/3 das flores ainda fechadas; coloração homogênea e formato uniforme; 15% das flores retas; flores comerciáveis a partir do segundo ano de cultivo; e exigência no controle de folhas a partir do sexto mês de cultivo. / Abstract: The global demand for excellence of floriculture products requires the use of appropriate technologies to ensure a good quality product. One important factor is the acquisition of selected plant propagation material, free of contamination, guaranteed by specialized laboratories. Aiming for the assessment of clones of the main brazilian variety of anthurium, this work was conducted to evaluate some preharvest and postharvest quality indices of plant growth and flowers, respectively. Anthurium andraeanum Lind. ('IAC Eidibel') was grown in closed hydroponic system with coconut fiber as growing media, with plants and flowers evaluated qualitative and quantitatively during the experimental period. As a result, the anthurium 'IAC Eidibel' presented: full adaptation and development in closed hydroponic system with coconut fiber; early production and plant height, constant and homogeneous; average production of one leaf/plant per month; constant increment of dry matter in leaves bigger than the increase in leaf area; greater accumulation of dry matter of spathe at the point of maturation with 1/3 of their flowers still immature; uniform color and shape of the spathes; an average stem strainghtness index of 15%; flowers at the commercial stage in the second year of cultivation and; prunning control of leaves after the sixth month of cultivation. / Doutorado / Tecnologia Pós-Colheita / Doutor em Engenharia Agrícola

Due to unique physical and chemical properties, engineered nanomaterials (ENM) have been used in more than 2000 products that are commercialized in various sectors including electronics, therapeutics, medical diagnostics, clothing, and personal care products. Increasing use and unique properties of ENMs have raised concerns for their potential to cause harm to the receptor organisms. Soil contamination of ENMs may occur due to land application of biosolids and wastewater, land disposal of nanoproducts, surface runoff, and atmospheric deposition. Little is known about the potential impact of ENMs to the terrestrial crop plants. Therefore, we investigated the potential developmental phytotoxicity of silver and zinc oxide nanoparticles (NP) on two agriculturally significant crop plant species, Zea mays (maize) and Brassica oleracea var. capitata (cabbage), using microscopic examination of the root anatomy, germination rate and root elongation measurements. Results showed that the NPs evaluated were less toxic to germination and root growth than Ag+ or Zn+2 treatment. Several anatomical alterations were observed in the primary root cells in maize with both NPs and their corresponding ionic salt treatments. Greater biouptake of Ag occurred with Ag+ treatment than with the nanosilver treatment in maize. The number of metaxylem vessels was also altered with nanosilver, Ag+, and Zn+2 treatments, but not with nanozinc oxide treatment. These findings suggest that the NPs and their ions may impair the growth and development of the terrestrial crop plants. To understand whether uptake of nanosilver by maize is of human health concern would require a human health risk assessment considering exposure to nanosilver via human consumption of edible crops such as maize and cabbage.