Recent Advances in Guayule Seed Germination Procedures<sup>1</sup>

Naqvi, Himayat H.; Hanson, George P.

doi:10.2135/cropsci1980.0011183x002000040020x

Cited by 33 publications

(9 citation statements)

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“…to GA 3 might also have been a factor. For example, germination of Parthenium argentatum Gray (Asteraceae) was enhanced more by GA 3 (200 mgÁL -1 ) when seeds were scarified for 2 h in sodium hypochlorite compared with nonscarified seeds treated with GA 3 (Naqvi and Hanson, 1980). The inability of moist preconditioning or soaking seeds in running tap water to improve staining also is consistent with a metabolic activity effect on staining.…”

Section: Resultsmentioning

confidence: 71%

Assessing Viability of Prevariety Germplasm of Native Coreopsis Species

Norcini¹,

Aldrich²

2008

horts

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Dormancy issues and lack of approved protocols have led to increasing use of the pregermination tetrazolium test to assess whether seeds of premium-priced, prevariety germplasm of native wildflower species are living and have the potential to germinate and develop normally under field conditions, that is, whether seeds are viable. A major concern is the limited amount of industrywide training on how to conduct and interpret results of tetrazolium (TZ) tests for the multitude of native species. Precise methods that yield uniform results are especially critical for testing of prevariety germplasm of native species given their high value and economic consequences of inaccurate test results. In preliminary work, we observed that embryos extracted from intact seeds of native Coreopsis species subjected to TZ testing were viable if they were turgid and appeared normal and were stained pink, red, or were pure white with or without the radicle tip stained pink to red. In this study, we conducted an in-depth analysis of TZ testing of intact seeds of prevariety germplasm of four native Coreopsis species to: 1) verify our preliminary conclusions; and 2) to determine if staining could be improved by preconditioning or gibberellic acid (GA3) because relatively low percentages of embryos of intact seeds stained pink or red. In addition, we evaluated two other methods to assess viability: the excised embryo test and emergence tests in soil and a soilless medium under ambient conditions. We confirmed that embryos extracted from intact seeds subjected to TZ testing were viable provided that embryos were turgid and appeared normal and were stained pink, red, or were pure white ± a pink to red radicle tip. Embryo staining was not consistently improved by moist preconditioning or GA3. Results of pregermination TZ tests of intact seeds and/or germination plus postgermination TZ tests of intact, nongerminated seeds were not consistently accurate and/or uniform across all species and seed lots, issues usually encountered in seed lots that were relatively dormant or of poor quality, and in postgermination TZ testing of seed lots with relatively low dormancy. Moreover, these issues are likely to be encountered even with standard TZ testing protocols given the widely accepted challenges of accurately interpreting TZ tests of native species in general. The most precise, uniform method of assessing viability was the excised embryo germination test because all viable seeds germinated, results were easy to interpret so the likelihood of false-positives or -negatives was nil, and results were very uniform across replications. Emergence tests under ambient conditions substantially underestimated viability. In summary, the high cost of prevariety germplasm seeds of native Coreopsis species, inherent genetic and phenotypic variability, and unknown dormancy characteristics warrant the use of the embryo excision test for determining viability and for increased sample sizes, especially for any tests involving TZ.

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Section: Resultsmentioning

confidence: 71%

Assessing Viability of Prevariety Germplasm of Native Coreopsis Species

Norcini¹,

Aldrich²

2008

horts

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“…Additional details on the above-mentioned plant materials are reported by Ilut et al [43]. Seeds were treated to break dormancy using the method of Naqvi and Hanson [44] and were sown in wet filter paper inside a growth chamber. Two weeks after germination, seedlings were moved into jiffy pots and afterwards put in plastic bags.…”

Section: Methodsmentioning

confidence: 99%

Bioactive Compounds from Leaves and Twigs of Guayule Grown in a Mediterranean Environment

Piluzza

Campesi

Molinu

et al. 2020

Plants

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Guayule (Parthenium argentatum) is one of the most promising alternatives to produce natural rubber. As the guayule leaves represent a waste byproduct in the rubber extraction process, their exploitation might contribute to the valorization of the whole plant biomass. The specific aim of our study was to determine the antioxidant capacity and the content of phenolic compounds in leaves and twigs of different guayule lines cultivated in a Mediterranean environment. The antioxidant capacity and the contents of phenolic were affected significantly by guayule accession and harvest time. Overall means in twigs represented about 60% of the corresponding leaf values for antioxidant capacity as DPPH (1,1-diphenyl-2-picrylhydrazyl) and not tannic phenolic and about 55% as ABTS (2,2′-azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt), total phenolic, tannic phenolic and total flavonoid contents. Five individual phenolic compounds were identified in methanolic extracts of leaves. Neochlorogenic acid (62.5–174.8 mg g−1 DW) and chlorogenic acid (28.6–41.1 mg g−1 DW) were the most abundant phenolic acids. In addition to the compounds quantified in leaves, cynarin was identified only in twigs and for the first time in guayule biomass. Our results indicate that guayule leaves and twigs represent a rich source of antioxidants for potential applications in fodder, nutraceutical and pharmacological sectors.

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“…Seeds (593, 11591, 11604, 4265XF, N576, and bulk collection) were first evaluated for germination using a procedure outlined by Naqvi and Hanson ( 1980). In brief, cleaned seeds were soaked in distilled water overnight, treated with 0.5 NaOCl solution for 2 h, then placed in petri dishes containing wet cotton fiber.…”

Section: Germination Testsmentioning

confidence: 99%

“…Guayule seeds treated in the same manner as the laboratory germination test (50 per pot) were spread over the smoothed potted soil and covered to a depth of0.5 em. Such a shallow seeding depth was used, since emergence decreases sharply with increasing seeding depth (e.g., Naqvi and Hanson, 1980). The potted soil surface was smoothed after seeding, and covered with a filter paper during watering to minimize surface disturbance.…”

Section: Emergence and Seedling Mortality Testsmentioning

confidence: 99%

Salt Effects on Emergence and Seedling Mortality of Guayule¹

Miyamoto¹,

Piela²,

Davies³

et al. 1984

Agronomy Journal

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Establishment of guayule (Parthenium argentatumGray) by direct seeding has been unreliable due to poor seedling emergence and subsequent mortality. Laboratory germination, greenhouse and small field plot tests were performed for evaluating possible salinity interactions. Guayule seeds (593, 11591, and bulk collection) germinated 60 to 85% in petri dishes containing high saline solutions (EC = 22 dSm−1). Yet, emergence from well‐watered sandy soils was reduced sharply with increasing salinity, e.g., less than 10% emergence at irrigation water salinity of 4.5 dSm−1in field plots irrigated twice a day. Seedling mortality was negligible when irrigated with distilled or low salt water, but increased with increasing salinity. Both emergence and seedling survival rates were highly correlated (r = −0.94) with the salinity of surface (0 to 1 cm depth) soil samples. Salts introduced through irrigation water accumulated mostly in the surface 0.5 cm of soils with concentrations ranging from 4 to 22 dSm−1in soil saturation extract. Salt concentrations at seeding depths (0.5 to 0.8 cm) were, however, low enough to allow seed germination. Low emergence and high seedling mortality observed here appeared to be related to hypocotyl and seedling damage by salts accumulated on soil surfaces. Such damage can occur in soils classified as nonsaline when irrigated with water having salinity as low as 1 dSm−1.

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Recent Advances in Guayule Seed Germination Procedures¹

Cited by 33 publications

References 0 publications

Assessing Viability of Prevariety Germplasm of Native Coreopsis Species

Assessing Viability of Prevariety Germplasm of Native Coreopsis Species

Bioactive Compounds from Leaves and Twigs of Guayule Grown in a Mediterranean Environment

Salt Effects on Emergence and Seedling Mortality of Guayule¹

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Recent Advances in Guayule Seed Germination Procedures1

Cited by 33 publications

References 0 publications

Assessing Viability of Prevariety Germplasm of Native Coreopsis Species

Assessing Viability of Prevariety Germplasm of Native Coreopsis Species

Bioactive Compounds from Leaves and Twigs of Guayule Grown in a Mediterranean Environment

Salt Effects on Emergence and Seedling Mortality of Guayule1

Contact Info

Product

Resources

About

Recent Advances in Guayule Seed Germination Procedures¹

Salt Effects on Emergence and Seedling Mortality of Guayule¹