Temperatures and qualities of light in Niger (Guizotia abyssinica (L.f.) Cass.) seeds germination in Mato Grosso do Sul, Brazil

For each vegetable species, there is a specific environment conditions to occur the seed germination process. However, there is a little information regarding the necessary conditions for Niger (Guizotia abyssinica (L.f.) Cass.) seeds germination. The aim of this research was to evaluate the influence of different temperatures and types of light on Niger (Guizotia abyssinica (L.f.) Cass.) seeds germination. Seeds were sown on two sheets of “germitest” paper inside plastic box type “gerbox” and placed on B.O.D. Treatments were constituted of two constant temperatures (15 ºC and 25 ºC, respectively) and an alternating temperature (20-30 ºC) under 10 hours for the lowest temperature and 14 hours for the highest temperature and they were associated to the wavelengths as follows: blue (440 nm), green (560 nm), red (660 nm), extreme red (730 nm), white light and dark. The experiment was conducted in a completely randomized design with four replicates of 50 seeds. Effects of different temperatures and qualities of light were evaluated by seeds germination and vigor. Higher germination of Niger seeds is observed in temperatures of 25 and 20-30 ºC and they can be considered as non-photoblastic.For each vegetable species, there is a specific environment conditions to occur the seed germination process. However, there is a little information regarding the necessary conditions for Niger (Guizotia abyssinica (L.f.) Cass.) seeds germination. The aim of this research was to evaluate the influence of different temperatures and types of light on Niger (Guizotia abyssinica (L.f.) Cass.) seeds germination. Seeds were sown on two sheets of “germitest” paper inside plastic box type “gerbox” and placed on B.O.D. Treatments were constituted of two constant temperatures (15 ºC and 25 ºC, respectively) and an alternating temperature (20-30 ºC) under 10 hours for the lowest temperature and 14 hours for the highest temperature and they were associated to the wavelengths as follows: blue (440 nm), green (560 nm), red (660 nm), extreme red (730 nm), white light and dark. The experiment was conducted in a completely randomized design with four replicates of 50 seeds. Effects of different temperatures and qualities of light were evaluated by seeds germination and vigor. Higher germination of Niger seeds is observed in temperatures of 25 and 20-30 ºC and they can be considered as non-photoblastic

Substrate water availability and seed water content on niger germination

Niger is an oleaginous species whose cultivation has been spreading, but there is not much information on the adverse conditions during its seedling establishment. This study aimed at evaluating the effects of substrate water availability and seed water content on niger germination. Seeds were moistened using the humid atmosphere method for 0; 24; 48; and 72 hours, obtaining the water contents of 7.0 %, 12.8 %, 16.8 % and 32.2 %. Then, they were sown in substrate moistened with PEG 6000 solutions with different osmotic potentials: 0.0 MPa (control), -0.1 MPa, -0.2 MPa, -0.3 MPa and -0.4 MPa. A completely randomized design, in a 4 x 5 factorial scheme (water content x osmotic potential), with four replications of 50 seeds, was used. First count and germination percentage, germination speed index and mean time, shoot and root length and seedlings dry weight were evaluated. The reduction in the substrate osmotic potential decreases the niger seed germination and seedling growth, regardless of water content, but with a higher evidence in seed water contents below 32.2 % and 12.8 %, respectively

Accelerated aging test in niger seeds

Abstract:Niger is a promising oilseed species for biodiesel production but there is no much information about the physiological potential of its seeds. Thus, the aim was to adapt the methodologies of accelerated aging test on six lots of niger seeds. The test was carried out by traditional and with saturated salt solution (20 and 40 g NaCl.100 mL-1) methods at 41 and 45 °C for 24, 48, 72 and 96 hours. After the decay period, the seeds were submitted to the germination test, proceeding to an evaluation on the seventh day after sowing, counting the normal seedlings percentage. A completely randomized design with four replications of 50 seeds was used and the means were compared by Tukey's test. The accelerated aging test was correlated with seedling emergence and provided lots classification in at least two levels of vigor. For the accelerated aging test, the method with 20 g NaCl.100 mL-1 at 41 °C for 24 hours is recommend. The traditional method is not suitable because it provides water content variation between samples above what is tolerable

Accelerated aging test in niger seeds

Abstract:Niger is a promising oilseed species for biodiesel production but there is no much information about the physiological potential of its seeds. Thus, the aim was to adapt the methodologies of accelerated aging test on six lots of niger seeds. The test was carried out by traditional and with saturated salt solution (20 and 40 g NaCl.100 mL-1) methods at 41 and 45 °C for 24, 48, 72 and 96 hours. After the decay period, the seeds were submitted to the germination test, proceeding to an evaluation on the seventh day after sowing, counting the normal seedlings percentage. A completely randomized design with four replications of 50 seeds was used and the means were compared by Tukey's test. The accelerated aging test was correlated with seedling emergence and provided lots classification in at least two levels of vigor. For the accelerated aging test, the method with 20 g NaCl.100 mL-1 at 41 °C for 24 hours is recommend. The traditional method is not suitable because it provides water content variation between samples above what is tolerable

Estresse salino na germinação de sementes e desenvolvimento de plântulas de niger (Guizotia abyssinica (L.f.) Cass.) Salt stress on seeds germination and seedlings development of niger (Guizotia abyssinica (L.f.) Cass.)

O processo de salinização dos solos e das águas subterrâneas e superficiais é um dos mais importantes problemas de degradação ambiental. O niger é uma herbácea anual com potencial para a produção de biodiesel, cujo comportamento em condições salinas ainda é desconhecido. Dessa forma, objetivou-se avaliar a germinação de sementes e crescimento de plântulas de niger submetidos a diferentes sais e concentrações. Os tratamentos utilizados corresponderam a três sais: cloreto de potássio (KCl), cloreto de cálcio (CaCl2) e cloreto de sódio (NaCl), associados a quatro potenciais osmóticos (-0,3; -0,6; -0,9 e -1,2 MPa). As sementes de niger semeadas diretamente sobre substrato umedecido com água destilada constituíram o controle. O efeito da salinidade na germinação das sementes foi avaliado pela porcentagem, tempo médio e índice de velocidade. As plântulas foram analisadas quanto ao comprimento da parte aérea e raiz e massas fresca e seca de plântulas inteiras. O delineamento estatístico adotado foi o inteiramente casualizado, constituindo-se de um fatorial 3x5 (sais x potenciais osmóticos) com quatro repetições de 50 sementes cada. As sementes de niger são sensíveis a salinidade. A exposição ao NaCl, KCl e CaCl2 a partir do potencial osmótico de -0,3 MPa reduz o poder germinativo e o crescimento de plântulas. Os sais inibem a germinação de sementes do niger no potencial de -1,2 MPa.The soil, and subterranean and superficial water saltiness process is one of the most important environment degradation problems. Niger is an annual herbaceous with biodiesel production potential, which seeds behavior is unknown in saline conditions. In this way, this work aimed to evaluate the niger seeds germination and initial seedlings growth submitted to different salt solutions. The treatments used constituted of three types of salts: NaCl, KCl and CaCl2 at four osmotic potentials (-0.3; -0.6; -0.9 e -1.2 MPa). The niger seeds sowed directly on substrate water moistured constituted the control treatment. The saline effects on seeds germination were evaluated though germination percentage, germination medium time and germination speed index. The Niger seedlings were analyzed through the shoot and root length and fresh and dried mass seedlings. The statistic design used was entirely casualized, constituted by a factorial 3x5 (salts x osmotic potentials) with four repetitions of 50 seeds. The Niger seeds are salinity sensitive. Seeds exposition to NaCl, KCl and CaCl2 reduces the germinative ability and the seedlings growth at -0.3 MPa. The salt solutions inhibit the Niger seeds germination at -1.2 MPa

Photosynthetic and enzymatic metabolism of Schinus terebinthifolius Raddi seedlings under water deficit

ABSTRACT Schinus terebinthifolius Raddi is a tree species that can be used in the recovery of degraded areas, as it exhibits rapid growth and has a very expansive root system, facilitating water uptake from the deeper layers of the soil. The objective of this study was to evaluate photosynthesis and enzymatic activity in S. terebinthifolius seedlings under conditions of water deficit and their potential to recover following re-irrigation. The experiment was conducted in a greenhouse under a plastic covering where plants were distributed into two groups: Group 1 - control plants, where irrigation was maintained at 70% of the water retention capacity, and Group 2 - stressed plants, where irrigation was suspended until the photosynthetic rate neared zero, followed by rehydration for 12 days, then a further suspension of irrigation. At the beginning of the experiment and during the suspension of irrigation and rehydration, plants were evaluated for gas and antioxidant enzyme exchanges. Hydric stress significantly reduced photosynthesis, stomatal transpiration conductance, carboxylation efficiency of Rubisco, and the chlorophyll content of the S. terebinthifolius plants. Following rehydration, plants recovered the carboxylation efficiency of Rubisco, but not the photosynthetic rate. Antioxidant enzyme activity increased in both the aerial part and the root in response to water deficit

Níveis de fertirrigação nas características morfofisiológicas de mudas de couve chinesa

A couve chinesa é uma hortaliça amplamente utilizada na alimentação humana. Tendo em vista a escassez de informações referentes à fertirrigação na produção de mudas de olerícolas, o objetivo do presente trabalho foi avaliar os efeitos de diferentes níveis de fertirrigação nas características morfofisiológicas de mudas de couve chinesa (Brassica pekinensis L.), utilizando o fertilizante 20-5-10 (NPK). O experimento foi conduzido em viveiro telado, na Universidade Federal da Grande Dourados (UFGD), em bandejas de isopor de 128 células. Foram realizadas duas fertirrigações, aos 5 e aos 12 dias após a emergência. Avaliou-se, aos 32 dias após a semeadura, o número de folhas, o comprimento da parte aérea e da raiz, as massas fresca e seca da parte aérea e da raiz, a área foliar e o teor de clorofila.  O delineamento experimental adotado foi o de blocos ao acaso, utilizando-se seis doses do fertilizante (0,0; 1,0; 2,0; 4,0; 8,0 e 16,0 g L-1), com quatro repetições. Os resultados indicaram que a dose de 9,8 g L-1 do fertilizante proporcionou maiores valores de comprimento e massa seca da parte aérea e menor comprimento das raízes, enquanto o número de folhas não sofreu interferência das doses utilizadas. Sendo assim, doses do fertilizante de até 10 g L-1 na água de irrigação são recomendadas para a produção de mudas de couve chinesa