X-Ray analysis to assess mechanical damage in sweet corn seeds

The X-ray test is a precise, fast and non-destructive method to detect mechanical damage in seeds. In the present study, the efficiency of X-ray analysis in identifying the extent of mechanical damage in sweet corn seeds and its relationship with germination and vigor was evaluated. Hybrid 'SWB 551' (sh2) seeds with round (R) and flat (F) shapes were classified as large (L), medium (M1, M2 and M3) and small (S), using sieves with round and oblong screens. After artificial exposure to different levels of damage (0, 1, 3, 5 and 7 impacts), seeds were X-rayed (15 kV, 5 min) and submitted to germination (25 °C/5 days) and cold (10 °C/7 days) tests. Digital images of normal and abnormal seedlings and ungerminated seeds from germination and cold tests were jointly analyzed with the seed X-ray images. Results showed that damage affecting the embryonic axis resulted in abnormal seedlings or dead seeds in the germination and cold tests. The X-ray analysis is efficient for identifying mechanical damage in sweet corn seeds, allowing damage severity to be associated with losses in germination and vigor.

Hydric restriction as vigor assessment method of soybean seeds

The objective of this study was to investigate the possibility of using hydric restriction as a method for evaluating vigor of soybean seeds. The soybean seeds, cultivar BRS 245RR, represented by four different seed lots, were characterized by germination and vigor. For the treatment of hydric restriction and temperature, the combination of substrate water potential and temperature were the following: deionized water (0.0 MPa); polyethylene glycol (PEG 6000) aqueous solution (-0.1, -0.3 and -0.5 MPa); and four temperatures (20 ºC, 25 ºC, 30 ºC, and 35 ºC), respectively. A completely randomized experimental design was used, with four replications per treatment, and the ANOVA was performed individually for each combination of temperature and water potential of substrate. According to results obtained, the test of hydric restriction has the same efficiency of the accelerated aging test in estimating vigor of soybean seeds, cv. BRS 245RR, when water potentials of -0.1 MPa or -0.3 MPa at a temperature of 25 ºC, or -0.3 MPa at a temperature of 30 ºC are used.

Assessment of physiological potential of cucumber seeds using the software Seedling Vigor Imaging System® (SVIS®)

The software Seed Vigor Imaging System (SVIS®), has been successfully used to evaluate seed physiological potential by automated analyses of scanned seedlings. In this research, the efficiency of this system was compared to other tests accepted for assessing cucumber (Cucumis sativus L.) seed vigor of distinct seed lots of Supremo and Safira cultivars. Seeds were subjected to germination, traditional and saturated salt accelerated aging, seedling emergence, seedling length and SVIS analyses (determination of vigor indices and seedling growth uniformity, lengths of primary root, hypocotyl and whole seedlings). It was also determined whether the definition of seedling growth/uniformity ratios affects the sensitivity of the SVIS®. Results showed that analyses SVIS have provided consistent identification of seed lots performance, and have produced information comparable to those from recommended seed vigor tests, thus demonstrating a suitable sensitivity for a rapid and objective evaluation of physiological potential of cucumber seeds. Analyses of four-days-old cucumber seedlings using the SVIS® are more accurate and growth/uniformity does not affect the precision of results.

Viability of recently harvested and stored Xylopia aromatica (Lam.) Mart. (Annonaceae) seeds

Xylopia aromatica is a native species from Brazil's "Cerrado", recommended for restoration ecology and also as a medicine. Its seeds have embryos with morphophysiological dormancy, making nursery propagation difficult. The objective of this study was to verify the efficiency of X-ray and tetrazolium tests for evaluating the viability of three seed lots, stored for different periods. All seeds were X-rayed (13 kV, 350 seconds) and samples used for tetrazolium and germination tests. In the tetrazolium test, seeds were submitted to six treatments at two temperatures (25 and 30 °C) with imbibition in distilled water and immersion in three concentrations of tetrazolium solution (0.5, 0.75 and 1%) at the two imbibition temperatures. Seeds for the germination test were placed for imbibition in distilled water and a 500 ppm Promalin® (6-Benzyladenine + GA4 + GA7) solution and later sown in sterilized sand. The embryo could not be observed with the X-ray test. However, those seeds observed with an undamaged endosperm did not differ in the percentages of seeds with firm and stained endosperms observed in the tetrazolium test for all the lots. The tetrazolium test is efficient for evaluating seed viability, principally if imbibed at 30 °C and immersed in a 0.5% solution at 30 °C.

Computerized imaging analysis of seedlings for assessment of physiological potential of wheat seeds

Nowadays, image analysis is one of the most modern tools in evaluating physiological potential of seeds. This study aimed at verifying the efficiency of the seedling imaging analysis to assess physiological potential of wheat seeds. The seeds of wheat, cultivars IAC 370 and IAC 380, each of which represented by five different lots, were stored during four months under natural environmental conditions of temperature (T) and relative humidity (RH), in municipality of Piracicaba, Stated of São Paulo, Brazil. For this, bimonthly assessments were performed to quantify moisture content and physiological potential of seeds by means of tests of: germination, first count, accelerated aging, electrical conductivity, seedling emergence, and computerized analysis of seedlings, using the Seed Vigor Imaging System (SVIS®). It has been concluded that the computerized analyses of seedling through growth indexes and vigor, using the SVIS®, is efficient to assess physiological potential of wheat seeds.

Physiological quality of osmoprimed eggplant seeds

Eggplant seeds germination can be slow and uneven, justifying the use of pre-germinative treatments to improve the performance of seed lots. One option of treatment is the controlled hydration of seeds by priming. In this way, this study aimed to evaluate the performance of eggplant seeds cv. Embu submitted to different methodologies of priming. The seeds used in the experiment were stored in cold chamber (15º C and 55% RH) in paper bags. The research was carried out at Central Laboratory of Seeds/UFLA. The seeds were submitted to the priming in aerated solutions varying the following factors: temperature (15º C and 25º C), time (24, 48 and 72 hours) and solution (water, PEG, KNO3 and PEG+KNO3). Seeds were washed in running water and dried at 30º C, until the return to the initial moisture content, around 10%. The variables analyzed were percentage of germination, percentage of emergence, speed index of emergence and electrical conductivity. The treatments were arranged in a completely randomized design, according to a factorial arrangement 2x3x4+1 (control - seeds without priming). The results showed that priming improves the vigour of eggplant seeds with no effect on viability; the priming in water or KNO3 is efficient to improve the seed vigour and priming in water or KNO3 may use temperature of 15º C or 25º C for 24, 48 or 72 hours.

Germination, carbohydrate composition and vigor of cryopreserved Caesalpinia echinata seeds

The present study investigated the germination and vigor of Caesalpinia echinata (Brazilwood) seeds stored at negative temperatures. Recently harvested seeds were cryopreserved at -18º or -196ºC and periodically evaluated for germination, seed vigor and carbohydrate composition. The temperatures did not influence the germination percentages or vigor. The germination percentage decreased from 88% in recently harvested seeds to 60% after 730 days of storage. The different temperature and storage times tested did not affect the vigor seed germination as indicated by the measures of plant growth and survival. The different temperatures used did not cause changes in the carbohydrate composition. The tegument cell walls were rich in lignin, arabinose and xylose. The cytoplasm of the cotyledons and embryos had high levels of glucose, fructose, and sucrose. The cryopreservation technique here presented was effective in the conservation of Brazilwood seeds for the medium term.