REVISTA CIENTÍFICA MULTIDISCIPLINAR NÚCLEO DO CONHECIMENTO ISSN: 2448-0959 https://www.nucleodoconhecimento.com.br PELTOPHORUM DUBIUM FRUIT PROCESSING INFLUENCE ON GERMINATION ORIGINAL ARTICLE REGNIER, Leonardo de Lima Pereira 1 REGNIER, Leonardo de Lima Pereira. Peltophorum dubium fruit processing influence on germination. Multidisciplinary Scientific Journal Knowledge Nucleus. Year 04, Ed. 10, Vol. 09, pp. 112-120. October 2019. ISSN:2448-0959 ABSTRACT Peltophorum dubium has gained economical relevance to its uses in forest plantations and agroforestry systems, but seedling production, establishment, and management information are still restricted. Thus, this study aimed to understand the influence of the fruits on P. dubium germination. About ten thousand fruits were evenly distributed between three replicas of each treatment: Integral fruits, cut fruits, and direct seed sowing. The material was kept in a greenhouse with white plastic covering and periodic irrigation system. Seeds did not germinate at the integral fruit treatment. All the studied indexes presented significant discrepancies, except to uncertainty index. Germination rate was close to other studies results. When kept inside the fruits, seeds require greater time to germinate, and when fruits were cut they present an intermediate pattern between direct seed sowing and integral fruits sowing. High and fast emergence of this species is probably associated with its ecological whole as early secondary. Keywords: Canafístula, Forestry seeds, Fabaceae, Seedling production. 1 Master’s student - Department of Botany, Institute of Biosciences University of São Paulo (USP) – Brazil. RC: 39784 Disponível em: https://www.nucleodoconhecimento.com.br/biology/germination REVISTA CIENTÍFICA MULTIDISCIPLINAR NÚCLEO DO CONHECIMENTO ISSN: 2448-0959 https://www.nucleodoconhecimento.com.br INTRODUCTION Peltophorum dubium (Spreng.) Taub. popularly know as Canafístula, is a Brazilian native species, which belongs to the Fabaceae family. It is widespread in southeast and south regions, but also present in west-center and northeast regions (SILVA; RANDO; CARVALHO, 2015). It is characterized as a helophyte, early secondary, anemochoric (fruits are dispersed by wind), high-tolerant to low temperatures, and a fast-growing species (CASTANHO, 2009; MATTEI; ROSENTHAL, 2002; MONTIEL; VERÓN, 2018). This species is mainly used as a wood source to civil construction, paper, furniture industry due to its resistance to high moisture and weather variations (MONTIEL; VERÓN, 2018). This species leaves aspect and tree-top form also provide its uses as ornamental (LORENZI, 2002; MATTEI; ROSENTHAL, 2002; VENTURIN et al., 1999). The fast-growing and widespread characteristics of this species led to its recent use of as an alternative to the wood industry in forest plantations (MONTIEL; VERÓN, 2018) and also agroforestry systems (SGARBOSSA et al., 2018). The P. dubium fruits are indehiscent (i.e. in natural conditions the fruits do not open and spread seeds to the environment) samaroid legumes (MONTIEL; VERÓN, 2018). Thus, understanding the germination behavior when seeds are retained by the fruit could also provide insights about this species seed bank dynamic. Relevant information to understand the ecologic behavior of this species. Ecological and economic information concerning about P. dubium seedling production, establishment and management are very restricted (GUERRA et al., 1982). Therefore, is essential to recognize the natural conditions that could promote or hampers germination. This species presents seed dormancy due to the structure of its tegument (PIROLI et al., 2005). This aspect has been extensively explored because dormancy is one of the most important defense mechanism against adverse environment conditions (PIROLI et al., 2005). Fruit processing is another important aspect to notice in seedling production perspective since it could reduce the production time because RC: 39784 Disponível em: https://www.nucleodoconhecimento.com.br/biology/germination REVISTA CIENTÍFICA MULTIDISCIPLINAR NÚCLEO DO CONHECIMENTO ISSN: 2448-0959 https://www.nucleodoconhecimento.com.br removing seeds from fruits is not necessary (REGNIER, 2019). Besides that, the influence of fruits in the germinating process of P. dubium has not been properly described. Being very difficult to recognize the germination behavior in a natural environment, when fruits are dispersed by wind. Fruit processing methods and their effects on germination have already been described to other Fabaceae family members (REGNIER, 2019). Thus, this study sought to understand the influence of the fruits on Peltophorum dubium germination. MATERIAL AND METHODS This study was conducted at the Harry Blossfeld plant nursery of São Paulo, situated in Cotia (23°36'30.0"S 46°50'48.9"W). According to Köppen’s climate classification, the study region presents Cwa, altitude tropical climate (SILVA; GENTILI, 2013). Featuring concentered rains during summer, dry winter, and the highest mean temperature above 22°C. Plant material was collected in the plant nursery region at the end of April of 2018. Harvesting method consisted of mature fruits gathered directly from tree-top. The material was kept in open plastic bags at room temperature during 20 days, seeking to dry the seeds (PIÑA-RODRIGUES et al., 2007) and to recognize the emergence of insects or pathogens. Fruit lot consisted of 10 863 units, and they were evenly distributed between three repetitions of each treatment. The control treatment consisted of direct sowing of integral fruits (Figure 1a). While in the second treatment all fruits had their edges around the seed removed with scissors (Figure 1b). In the third treatment, seeds were removed from the fruits (Figure 1c) and proceeded to sow. As this study did not seek to understand the influence of dormancy on germination, and P. dubium seeds are easier attacked by pathogens after the scarification (MATTEI; ROSENTHAL, 2002), they were not submitted to any processing. In sequence, fruits and seeds were planted in white trays containing vermiculite as substrate. After all treatments, the plastic trays containing the fruits and seeds were kept at greenhouse with white plastic covering RC: 39784 Disponível em: https://www.nucleodoconhecimento.com.br/biology/germination REVISTA CIENTÍFICA MULTIDISCIPLINAR NÚCLEO DO CONHECIMENTO ISSN: 2448-0959 https://www.nucleodoconhecimento.com.br and a fogging watering system with periodic activation every 35 minutes. Plant emergence was recorded about 70 days after seeding, with measurements nearly every 7 days. Figure 1. Adopted fruit processing treatments: a) Integral fruits; b) Fruits with edges cut; c) seeds of Peltophrum dubium. Gray represents the sowed parts. (JARDIM, 2019) The evaluation consisted in the use of indexes as mean germination time, also known as mean length of incubation time (RANAL; SANTANA, 2006), and the standard deviation was calculated as proposed by Haberlandt in 1875 (LABORIAU, 1983). All the other indexes were calculated as presented in Ranal e Santana (2006). RC: 39784 Disponível em: https://www.nucleodoconhecimento.com.br/biology/germination REVISTA CIENTÍFICA MULTIDISCIPLINAR NÚCLEO DO CONHECIMENTO ISSN: 2448-0959 https://www.nucleodoconhecimento.com.br All data were compiled to Excel component of Microsoft Corporation Office pack. Most usual germination indexes were obtained and graphically represented through GerminaQuant software (LOZANO‐ISLA; BENITES‐ALFARO; POMPELLI, 2019), and also all the statistical tests using the individual data of the replicas. The results were tested by ANOVA and in sequence submitted to Tukey test with a critical p-value of 1% (p < 0.01). RESULTS AND DISCUSSION Some indexes require at least one germination to its value estimation. During the analysis period, there was no seedling emergence to the control group (Integral fruit sowing), which made the estimation of mean germination rate (MGR), mean germination time (MGT), germination speed (GSP) and synchrony (SYN) indexes not possible. Only the uncertainty index did not present statistical differences between the treatments (Figure 2). While the integral fruits sowing treatment no seeds germinated, cutting the edges of the fruits provided an intermediate response of germination. When the fruits had their edges cut, the germination rate, speed, and synchronization are lower, and time required to germination is higher than the observed values to direct sowed seeds. RC: 39784 Disponível em: https://www.nucleodoconhecimento.com.br/biology/germination REVISTA CIENTÍFICA MULTIDISCIPLINAR NÚCLEO DO CONHECIMENTO ISSN: 2448-0959 https://www.nucleodoconhecimento.com.br Figure 2. Germination Proportion (GRP), Mean germination rate (MGR), Mean germination time (MGT), Germination speed (GSP), Synchronization index (SYN) and Uncertainty index (UNC) according to fruit treatment. Integral fruits (I), fruits with edges removed (II), direct seed sowing (III). Lowercase letters present the statistical differences adopting p<0.01. Error bars presents a standard error. In general, Peltophorum dubium documented germination rate, of non-processed seeds, is about 40% (CASTANHO, 2009; PIÑA-RODRIGUES et al., 2007). In this study, the mean germination proportion, also denominated as germination rate, reached 32.5%. Relatively close to the mentioned studies results. However, this RC: 39784 Disponível em: https://www.nucleodoconhecimento.com.br/biology/germination REVISTA CIENTÍFICA MULTIDISCIPLINAR NÚCLEO DO CONHECIMENTO ISSN: