Deborah de Souza Vidigal

Teste de envelhecimento acelerado em sementes de pimenta

The objective of this study was to adequate the methodology of accelerated aging test for vigor evaluation of pepper seeds. Six seed lots of pepper were tested for germination, germination at first count, cool germination and accelerated aging. For accelerated aging, the following methods were tested: traditional (100% RH) and modified (76% RH), at 38, 42 and 45oC for 48, 72 and 96 hours. The accelerated aging test was efficient for vigor evaluation of pepper seeds producing results similar to the first count and cool germination test, especially when conducted at 38 or 42oC for 96 hours by both traditional and modified methods.

Qualidade fisiológica de sementes de tomate em função da idade e do armazenamento pós-colheita dos frutos

The objective of this study was to evaluate the effects of age and post-harvest storage period of tomato fruits (Kada cv, Santa Cruz group) on seed quality. Fruits were harvested at 40, 50 and 60 DAA and stored for 0, 4, 8 and 12 days before seed extraction. The seeds were fermented for two days at 25oC to remove the mucilage. The following characteristics were evaluated: seed moisture and dry matter content, standard germination, first count, speed emergence index, accelerated aging and electrical conductivity. The post-harvest storage of fruits harvested at 60 DAA reduced the seed quality. For the fruits harvested at 50 DAA, 8 days-storage contributed to increasing the speed of emergence. Early harvest (40 DAA) was beneficial to physiological seed quality, when related to post harvest fruit storage for 12 days.

Teste de condutividade elétrica para semente de pimenta

This study was carried out with the objective of verifying the effect of pepper seeds number, water volume and imbibition period on the electrical conductivity test results and correlating these data with germination, first count, accelerated aging and seedling length tests results. The electrical conductivity test was conducted with 25 and 50 seeds per replication, imbibed in 25 and 50 mL of water at 25oC for 1, 2, 3, 4, 5, 6, 7, 8, 12, 16, 24, and 48 hours. The electrical conductivity test was efficient to evaluate pepper seeds vigor, but 25 showed to be an inadequate number of seeds when the objective was to identify seed lot vigor level. Better results were obtained when samples of 50 seeds, soaked for 1 hour in 25 mL of water were used.

Validation of the software SEEDSOLVE for predicting losses of germination and vigor of stored seeds.

The objective of this study was validate the software SEEDSOLVE for predicting the germination and vigor losses in stored orthodox seeds. The validation was accomplished by comparing the calculated and experimental values of the germination and vigor losses in three seed lot sof corn and soybean stored in the laboratory, during a period of 210 days. The corn and soybean seeds, with three levels of moisture content (11, 13, and 15% for corn and 9, 11, and 13% for soybean), were packed in polyethylene bags and stored in incubators at three temperatures (15, 25, and 35oC). The results of the comparisons of the calculated and experimental data of germination and vigor that occurred during the storage of the three seed lots, under different storage conditions, allowed the conclusion that the SEEDSOLVE predicted the germination and vigor losses in stored corn and soybean seeds with reasonable precision.

Influência de temperatura, luz e giberelina na germinação de sementes de Thlaspi caerulescens J. Presl & C. Presl (Brassicaceae)

Thlaspi caerulescens is a natural zinc (Zn), cadmium (Cd) and nickel (Ni) hyperaccumulator, a model species to study heavy metal hyperaccumulation and tolerance. However, the quick loss of viability under storage and the low production of seeds under non temperate climates justify the need to identify conditions to maximize germination and seed vigor. In order to characterize better conditions for germination, seeds of T. caerulescens were incubated under a photoperiod of 8h light/16h dark (15 mmol.m-2.s-1) or in darkness, at temperatures of 10, 15, 20 and 25oC. The assays were performed with germination paper wetted with 0,05% giberelic acid or distillated water. Percentage of germination (G%), and germination speed index (GSI) were evaluated. The highest percentage of germination (66%) was recorded for the treatments with GA at the temperatures of 15 and 20oC. The highest GSI was recorded for the treatments with GA at 15o and 20oC, independent of the light effect. The highest germination and germination speed index for T. caerulescens were obtained with the GA3 treatment, under light, and temperatures between 15 and 20oC.

Equating the initial quality of corn and soybean seed for application in the probit model

The objective was to equate the initial quality of the seeds (Ki), used in the probit model for predicting the longevity of corn (Zea mays) and soybean (Glycine max), as a function of the result of the initial tests of germination and accelerated ageing. Eleven seed lots of different corn and soybean cultivars were submitted to the tests of germination (TG), accelerated ageing (TEA), cold without soil (TF), for corn, and tetrazolium (TZ), for soybean, and to accelerated ageing tests, with constant conditions of moisture content and temperature of the seeds, to determine the value of Ki. Literature data with results of TEA and TF for corn and TEA and TZ for soybean were also used in this research. Simple and multiple linear regression analyses were conducted to equate: a) Ki as a function of TG and TEA for corn and soybean; b) TEAm (accelerated ageing of corn) as a function of TF; c) TEAs (accelerated ageing of soybean) as a function of TZ. The equations obtained were: Ki = 0,4230 + 0,4464 TG + 0,4131 TEA TEAM = - 0,4408 + 1,214 TF TEAS = - 0,1872 + 0,9875 TZ. The Ki equation presented an adjusted determination coefficient (r2) of 0,80 (d.p. 0,18 probit and parameters significant in p < 0,01, p < 0,02 e p < 0,05, respectively). The TEAm equation presented r2 of 0,80 (d.p. 0,24 probit and parameters significant in p < 0,002). The TEAs equation presented r2 of 0,84 (d.p. 0,18 probit and parameters significant in p < 0,005). The value of Ki can be equated as a function of the result of the initial tests of germination and vigor for corn and soybean (TEA or TF for corn and TEA or TZ for soybean).

GERMINAÇÃO E MORFOLOGIA DO DESENVOLVIMENTO PÓS-SEMINAL DE SEMENTES DE NIM-INDIANO (Azadirachta indica A. Juss. - MELIACEAE) 1

Azadirachta indica A. Juss. is a native specie of the arid areas of Asia and Africa, but nowadays is also distributed in America and other areas with tropical and sub-tropical climate. It is a very resistant plant that presents excellent medicinal properties. The objective of this study was to define the ideal germination conditions for neem (Azadirachta indica A. Juss.) seeds evaluating the most appropriate substrates, temperature and characterizing its post-seminal morphology. Seeds were sown on vermiculite, sand and towel paper and maintained in a germinator at 25°C, 30°C, 35°C and 20-30°C. A complete randomized design was used, with 25 seeds sown in four replications, and the germination percentage was evaluated. The best results were obtained for temperature of 35°C in vermiculite and towel paper substrates and countings performed at 15 and 30 days after sowing. Normal seedlings were classified as epigeal germination.

Caracterização morfológica e germinação de sementes de jalapa (Operculina macrocarpa (L.)Urb.)

The objective of this study was to evaluate the presence of tegumentar dormancy and identify pre-germination treatments that can unify and accelerate the germination and know the morphology of the seminal development in post-seed of Operculina macrocarpa. The seeds were subjected to the following pre-germination treatments: immersion in water for 1 hour; immersion in hypochlorite solution for 1 hour and the control, represented by seeds without pretreatment. Germination and emergence tests were conducted with four replications of 25 and 20 seeds, carried out in the laboratory and greenhouse, respectively. Evaluations were conducted daily, for 30 days and the percentage of normal seedlings (15 and 30 days) and the rate of speed germination/emergency were calculated. The germination of Operculina macrocarpa is epigeous-phanerocotylar and the seed, although it has a hard seed coat, was not shown to be impermeable to water and thus does not require pre-germination treatments.