Seed Biologists Beware: End-of-Trial Estimation of Initial Viability May Be Error-Prone Due to Unexpected Seed Death during the Experiment

Seed viability is routinely measured on seeds that fail to germinate at the end of an experiment. Together with the number of germinants, this is used to estimate viability of the seeds at start of the experiment (i.e., initial viability) and provides the comparative basis on which germination success is determined. We used this standard procedure on 40 Leucadendron species subjected to oscillating temperatures, heat and/or smoke pre-treatments to examine the extent to which they raised germination levels above that of the untreated controls. 16 species showed significantly different levels of estimated initial seed viability between treatments when they should have been unaffected. Loss of viability during the trial was an order of magnitude greater than annual loss during cold storage, which was usually negligible. Lowest levels of estimated initial viability occurred among the poorly germinating controls and confirmed that the heat and smoke treatments had little effect on viability. Species with soil-stored seeds were more vulnerable to this artefact than those with plant-stored seeds. We caution against the routine use of end-of-trial germination and viability of ungerminated seeds as an estimate of initial viability in determining germination success of various treatments. The preference is for estimates of initial viability to be undertaken on a separate sample of seeds in association with the trial.

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Seed Biologists Beware: Estimates of Initial Viability Based on Ungerminated Seeds at the End of an Experiment May Be Error-Prone

10.20944/preprints202109.0256.v3 ◽

2021 ◽

Author(s):

Byron B. Lamont

Keyword(s):

Seed Viability ◽

Separate Sample ◽

Prolonged Duration ◽

Germination Success

Seed viability is routinely measured on seeds that fail to germinate at the end of an experiment. Together with the number of germinants, this is used to estimate viability of the seeds at start of the experiment (i.e., initial viability) and provides the comparative basis on which germination success is determined. Perusal of the literature shows that sometimes (perhaps often, as the problem has yet to be recognized or reported) prolonged duration in the treatment, especially the control where little germination occurs, can lead to loss of viability. This results in underestimation of initial viability if that treatment is used. I caution against the routine use of end-of-trial germination and viability of ungerminated seeds as an estimate of initial viability in determining germination success of various treatments. I explore ways to deal with the problem but the preference is for estimates of initial viability to be undertaken on a separate sample of seeds concurrently with the experiment as this avoids the risk of seed death during the trial.

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Seed Biologists Beware: Estimates of Initial Viability Based on Ungerminated Seeds at the End of an Experiment May Be Error-Prone

10.20944/preprints202109.0256.v2 ◽

2021 ◽

Author(s):

Byron B. Lamont

Keyword(s):

Seed Viability ◽

Separate Sample ◽

Prolonged Duration ◽

Germination Success

Seed viability is routinely measured on seeds that fail to germinate at the end of an experiment. Together with the number of germinants, this is used to estimate viability of the seeds at start of the experiment (i.e., initial viability) and provides the comparative basis on which germination success is determined. Perusal of the literature shows that sometimes (perhaps often, as the problem has yet to be recognized or reported) prolonged duration in the treatment, especially the control where little germination occurs, can lead to loss of viability. This results in underestimation of initial viability if that treatment is used. I caution against the routine use of end-of-trial germination and viability of ungerminated seeds as an estimate of initial viability in determining germination success of various treatments. I explore ways to deal with the problem but the preference is for estimates of initial viability to be undertaken on a separate sample of seeds concurrently with the experiment as this avoids the risk of seed death during the trial.

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A method of precise misorientation determination

Journal of Applied Crystallography ◽

10.1107/s0021889803015905 ◽

2003 ◽

Vol 36 (6) ◽

pp. 1319-1323 ◽

Cited By ~ 5

Author(s):

A. Morawiec

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Spatial Resolution ◽

Standard Procedure ◽

Good Spatial Resolution ◽

Transmission Electron ◽

Order Of Magnitude ◽

Achievable Accuracy ◽

Better Than

A method that improves the accuracy of misorientations determined from Kikuchi patterns is described. It is based on the fact that some parameters of a misorientation calculated from two orientations are more accurate than other parameters. A procedure which eliminates inaccurate elements is devised. It requires at least two foil inclinations. The quality of the approach relies on the possibility to set large sample-to-detector distances and the availability of good spatial resolution of transmission electron microscopy. Achievable accuracy is one order of magnitude better than the accuracy of the standard procedure.

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Quantitative reduction of triphenyl tetrazolium chloride as a measure of viability in cereal seeds

Australian Journal of Experimental Agriculture ◽

10.1071/ea9720517 ◽

1972 ◽

Vol 12 (58) ◽

pp. 517 ◽

Cited By ~ 10

Author(s):

RL Harty ◽

LG Paleg ◽

D Aspinall

Keyword(s):

Sample Size ◽

Standard Procedure ◽

Seed Viability ◽

Close Correlation ◽

Triphenyl Tetrazolium Chloride ◽

Tetrazolium Chloride ◽

Enzyme Systems ◽

Dehydrogenase Enzyme ◽

Viable Seeds ◽

Extracting Solvent

The reduction of 2,3,5-triphenyl tetrazolium chloride (TTC) to a coloured formazan derivative by dehydrogenase enzyme systems in viable seeds has been examined. TTC reduction occurs in dry but not wetmilled tissue and the coloured product could be extracted by any of several organic solvents. This formazan product was estimated spectrophotometrically at 480 nm. The influence of fineness of grinding the tissue, TTC concentration, period of treatment, sample size, vacuum infiltration of the milled tissue with TTC and of extracting solvent were examined and a standard procedure is suggested. Using this procedure, a close correlation between seed viability and TTC reduction was demonstrated. The advantages of this method over the widely used topographical method for estimating seed viability with TTC are discussed.

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Effects of desiccation of seeds in nine species with morphophysiological dormancy on germination and embryo growth

Journal of Plant Ecology ◽

10.1093/jpe/rtaa083 ◽

2020 ◽

Author(s):

Miguel A Copete ◽

José M Herranz ◽

Raquel Herranz ◽

Elena Copete ◽

Pablo Ferrandis

Keyword(s):

Seed Viability ◽

Intermediate Complex ◽

Growth Stages ◽

Morphophysiological Dormancy ◽

Anthriscus Sylvestris ◽

Germination Ability ◽

Clematis Vitalba ◽

Narcissus Pseudonarcissus ◽

Different Levels ◽

Late Embryo

Abstract Aims In species with morphophysiological seed dormancy (MPD), little is known about the effects of desiccation of imbibed seeds on embryo growth and germination. We studied seed responses to dehydration in nine species with different levels of MPD. Methods For each species, a control test was conducted by keeping seeds permanently hydrated and exposed to the optimal stratification-incubation sequence to promote embryo growth. Simultaneously, tests were run in which seed stratification was interrupted for 1 month by desiccation at room temperature. Important Findings In Clematis vitalba and Ribes alpinum, with nondeep simple MPD, desiccation affected neither embryo growth nor seed viability, but the desiccation led to a decrease of germinative ability in R. alpinum by 16%. The seeds of Narcissus pseudonarcissus subsp. munozii-garmendiae, with deep simple epicotyl MPD, tolerated desiccation in different embryo growth stages, but their germinative ability decreased slightly. The response of species with complex levels of MPD to desiccation was more variable: Delphinium fissum subsp. sordidum, with intermediate complex MPD, and Anthriscus sylvestris and Meum athamanticum, both with deep complex MPD, tolerated desiccation. In contrast, Ribes uva-crispa with nondeep complex MPD, Lonicera pyrenaica with intermediate complex MPD, and Chaerophyllum aureum with deep complex MPD, had diminished germination ability by desiccation. Although seeds of the species with simple levels of MPD tolerated desiccation, those of some species with complex levels were also highly tolerant. Thus, desiccation did not induce secondary dormancy in late embryo growth stages. The desiccation tolerance of imbibed seeds of most of the nine species may show their adaptability to climate change in the Mediterranean region.

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Methodology of the tetrazolium test for assessing the viability of seeds of Eugenia brasiliensis Lam., Eugenia uniflora L. and Eugenia pyriformis Cambess

Journal of Seed Science ◽

10.1590/2317-1545v36n41029 ◽

2014 ◽

Vol 36 (4) ◽

pp. 427-434 ◽

Cited By ~ 6

Author(s):

Edmir Vicente Lamarca ◽

Claudio José Barbedo

Keyword(s):

Electrical Conductivity ◽

Seed Viability ◽

Important Method ◽

Eugenia Uniflora ◽

Fruit Species ◽

Incubation Periods ◽

Physiological Quality ◽

Different Levels ◽

Tetrazolium Test

Eugenia brasiliensis Lam. ("grumixameira"), Eugenia uniflora L. ("pitangueira") and Eugenia pyriformis Cambess. ("uvaieira") are forest and fruit species of pharmacological and gastronomic potential and have desiccation-sensitive seeds. The development of quick viability tests for the assessment of physiological quality of these seeds is needed. The tetrazolium test is an important method providing fast assessment of the seed physiological quality. Thus, this work aimed to develop a method for the tetrazolium test for determining viability of "grumixameira," "pitangueira" and "uvaieira" seeds. Initially the seeds of these species were soaked in water for 3 h at 25 ºC. Three concentrations of tetrazolium solutions were analyzed (0.100 %, 0.125 % and 0.250 %) for seed staining using three incubation periods (2, 3 and 6 h) at 35 ºC in the dark. After staining, seed viability was determined. Then, the seeds were subjected to different levels of controlled drying and were analyzed for their physiological quality by germination and electrical conductivity tests. The tetrazolium test is a suitable tool for determining viability after staining the seeds at 35 ºC using a 0.250 % concentration solution for 3 hours for "grumixameira" seeds, 0.125 % for 3 hours for "pitangueira" seeds and 0.100 % for 2 hours for "uvaieira" seeds.

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Activities of enzymes in β-carboxylation reactions and of catalase in cell-free preparations from the symbiotic dinoflagellates Symbiodinium spp. from a coral, a clam, a zoanthid and two sea anemones

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1986.0065 ◽

1986 ◽

Vol 228 (1253) ◽

pp. 483-492 ◽

Cited By ~ 16

Keyword(s):

Malate Dehydrogenase ◽

Sea Anemones ◽

Stony Coral ◽

Enzyme Systems ◽

Glycollate Dehydrogenase ◽

Order Of Magnitude ◽

Symbiotic Dinoflagellates ◽

Tridacna Maxima ◽

First Time ◽

Different Levels

Cell-free extracts of cultured and freshly isolated symbiotic dinoflagellates, Symbiodinium spp, isolated from the stony coral Montipora verrucosa , the clam Tridacna maxima , the zoanthid Palythoa sp. and the sea anemone Aiptasia pulchella were assayed for the enzyme systems involved in β-carboxylation and photorespiration. Markedly different levels of phosphoenolpyruvate carboxylase (EC 4 . 1 . 1 .31; PEP-case) activity were demonstrated in extracts from the different algae. The activity of PEP-case in the algae from M. verrucosa was highest, being an order of magnitude higher than PEP-case in algae from Palythoa sp. and up to 25-fold higher than that in algae from A. pulchella and T. maxima . The algae from M. verrucosa also exhibited pyruvate-P i dikinase (EC 2 . 7 .9 .1) activity. When these data are combined with previous demonstrations of the existence of NAD malate dehydrogenase and NADP malate dehydrogenase (decarboxylating; ‘malic enzyme’) in these algae, the indications are that they possess functional β-carboxylation enzyme systems. Past demonstrations of the photoassimilation of 14 CO 2 into glycollate by Symbiodinium spp. indicated photorespiration. The demonstration for the first time of activity of catalase (EC 1 . 11 . 1 . 6) when viewed in light of previous demonstrations of other composite enzymes of the photorespiratory pathway (e.g. phosphoglycollate phosphatase, glycollate dehydrogenase), add further confirmation to the disputed existence of a functional photorespiratory system in these symbiotic dinoflagellates.

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Coagulation-filtration of a secondary effluent by means of pre-hydrolyzed coagulants

Water Science & Technology ◽

10.2166/wst.1996.0675 ◽

1996 ◽

Vol 33 (10-11) ◽

pp. 193-201 ◽

Cited By ~ 5

Author(s):

Evangelos Diamadopoulos ◽

Christos Vlachos

Keyword(s):

Metal Salts ◽

Secondary Effluent ◽

Uv Absorbance ◽

Optimal Conditions ◽

Turbidity Removal ◽

Direct Filtration ◽

Order Of Magnitude ◽

Filter Bed ◽

Hydrolysis Of ◽

Different Levels

Jar tests were applied to a secondary effluent in order to determine optimal conditions for coagulation. The metal salts Al2(SO4)3, AlCl3 and FeCl3 were used as coagulants, and their efficiency under various degrees of pre-hydrolysis was examined. The variables under examination were the dose of the coagulant, the degree of pre-hydrolysis, B=[OH−]/[Me+3], and the pH at two different levels (pH=5.5 and pH=7.5). The efficiency of the various coagulants was evaluated for the removal of turbidity, phosphorous, COD and UV absorbance at 254 nm. The results showed that as far as turbidity removals are concerned, pre-hydrolysis of the aluminum and ferric chloride coagulants at values of B equal to 0.5 to 1 gave optimal results. However, for phosphorous removal, the higher the degree of pre-hydrolysis, the lower the removal of phosphorous. No remarkable differences were observed for the removal of organic matter measured as COD, while alum gave the best results for the reduction in UV absorbance at 254 nm. Direct filtration of the effluent showed that the coagulant dose required was an order of magnitude lower than that required for coagulation. 35 cm of filter bed were sufficient for effective filtration. All coagulants performed well, increasing the degree of turbidity removal as compared to the absence of coagulants. The lowest headloss rate was observed when alum was used, while the highest headloss rate, almost three times as much, when the aluminum chloride coagulants were used (with and without pre-hydrolysis). Ferric coagulants, with or without pre-hydrolysis, demonstrated intermediate headloss rates.

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