Emergência e crescimento inicial de plântulas de Swietenia macrophylla (King) em função da posição da semente e presença do endocarpo

Abstract

PALAVRAS-CHAVE RESUMO:O mogno (Swietenia macrophylla King) é uma Meliaceae de alto potencial econômico, encontrada nas florestas de terra firme da Amazônia brasileira, sendo uma das espécies mais exploradas no Brasil e por isso ameaçada de extinção. O estudo objetivou avaliar o efeito da posição de semeadura e presença de endocarpo na emergência e crescimento inicial de plântulas de S. macrophylla. O delineamento foi inteiramente ao acaso, com quatro repetições de 25 sementes, disposto em esquema fatorial 3 × 2 (posições e endocarpo). Os tratamentos consistiram em diferentes posições das sementes no substrato tendo como referência o poro germinativo: 0° -poro germinativo voltado para cima -PGC; 90° -poro germinativo voltado para o lado -PGL; 180º -poro germinativo voltado para baixo -PGB. Foram avaliados: a percentagem de emergência, tempo médio de emergência, diâmetro do coleto, número de folhas, altura da parte aérea, comprimento de raiz, massa seca da parte aérea e massa seca da raiz. As posições da semente afetam o percentual e o tempo médio de emergência de plântulas de S. macrophylla. A posição 0º proporciona maiores porcentagens de emergência e menor tempo médio de emergência. Para favorecer a emergência e crescimento inicial de plântulas de S. macrophylla, a semeadura deve ser realizada com o poro de germinação da semente voltado para cima, sem a presença do endocarpo. ABSTRACT: Mahogany (Swietenia macrophylla King) is a high economic potential Meliaceae found in an upland forest of the Brazilian Amazon, one of the most exploited species in Brazil and because of that is endangered. The study aimed to evaluate the effect of sowing position and presence of endocarp in the emergence and initial growth of S. macrophylla seedlings. The design was completely randomized with four replications of 25 seeds, arranged in a factorial 3 × 2 (positions and endocarp

Seedling production of Bertholletia excelsa in response to seed origin and position inside fruit

“…The distribution of germination over time in polynomial curves ( Figures 3A and 3B) followed the standard model of germination found in most tree species (Czabator, 1962). This kind of germination is featured by three different periods: initial, where the increase in germination percentage is slow (water absorption time), followed by a period of higher germination, and finally a period of decrease in the germination rates (Dionisio et al, 2017). The long period demanded for germination of B. excelsa seeds found in this study (30-160 days) can be related to their genetic variability and level of the embryo maturation of the sampled seeds.…”

Production of Bertholletia excelsa Humb. & Bonpl., (Lecythidaceae) seedlings in microenvironments under different substrates

“…Sand has been reported as an excellent substrate to maintain viability of stored seeds of B. excelsa (Silva et al, 2009) and germination of many tree species (Dionisio et al, 2017;Marques et al, 2018a).…”

“…Seedlings production is one of the most important activities in the process of setting forest stands, since the seedlings quality implies in the success of these forest stands. Projects on the recovery of degraded areas, commercial reforestation, and harvesting and conservation of native commercial species largely depend on the production of high quality seedlings (Dionisio et al, 2017;Marques et al, 2018b). In this way, it is essential the research and development of techniques to make it viable the seedlings production of native commercial species under low cost.…”

Substrates based on swine wastewater in the production of seedlings of Guazuma ulmifolia (Malvaceae)

“…Projects aimed at the recovery of degraded areas, commercial reforestation, conservation, or exploitation of forest species depend on the availability of seedlings with a certain quality level (Dionísio et al 2017;Marques et al 2018), like being healthy, growing vigorously with robust stems, and being free from disease, these Rodriguésia 73: e00712021. 2022 characteristics can be evaluated through biometric measurements and visual aspects.…”