Regulation of Germination of Seed of Anigozanthos manglesii

1994 ◽  
Vol 42 (2) ◽  
pp. 191 ◽  
Author(s):  
N Sukhvibul ◽  
JA Considine

Germination of seed of Anigozanthos (Haemodoraceae) species is usually low and unreliable which hinders the propagation of sexually generated progeny, impedes plant breeding activities and their use in horticulture. This study was undertaken to investigate the basis of these germination problems. Seeds of cultivated Anigozanthos manglesii D. Don. were shown to possess two mechanisms for regulating seed germination, both of which were external to the embryo. Embryos germinated freely on excision and culture on nutrient agar. This first barrier is a physico-chemical barrier and can be eliminated by a brief treatment with 5 M KOH and less effectively by physical abrasion with 50% H2SO4 or 0.7% NaOCl. Release of this barrier was correlated with permeability to fluorescein diacetate (FDA) and this proved to be a more useful indicator of seed viability than 2,3,5-triphenyl tetrazolium chloride (TTC). The other barrier was physiological and could be eliminated by treatment with GA3 or KNO3. Treatment of A. viridis Endl., A. humilis Lindley and A. flavidus DC. with KOH or H2SO4 with or without GA(3) elicited a small, a nil or negative response showing that mechanisms of control of germination may differ between taxa. Observations on the effects of temperature and duration of storage suggest mechanisms which may be significant in natural systems: moist stratification at 5°C caused reduced germination but sustained viability (as assessed by FDA) while dry seed stored at room temperature, showed increased germination with increasing duration of storage. The chilling response may indicate the capacity to initiate secondary dormancy under unfavourable germination conditions.

1972 ◽  
Vol 12 (58) ◽  
pp. 517 ◽  
Author(s):  
RL Harty ◽  
LG Paleg ◽  
D Aspinall

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.


2007 ◽  
Vol 21 (1) ◽  
pp. 141-144 ◽  
Author(s):  
Charles T. Bryson ◽  
Clifford H. Koger ◽  
John D. Byrd

Cogongrass, a rhizomatous perennial, is among the world's most troublesome weeds. Research was conducted at the Southern Weed Science Research Unit, Stoneville, MS, to determine cogongrass rhizome mortality with increasing temperature and duration of exposure to heat and to determine if 2,3,5 triphenyl tetrazolium chloride (TTC) could be used to evaluate cogongrass rhizome mortality following heat treatment. Cogongrass rhizome mortality was 100% at 65, 79, 93, 107, 121, 149, 177, and 187 C at time periods greater than or equal to 25, 5, 2.5, 2.5, 2.5, 2, 2 and 1 min, respectively. The duration of heat required for cogongrass mortality decreases as temperature increased. The standard greenhouse bioassay was more effective than tetrazolium chloride in predicting viability of cogongrass rhizomes following heat treatments.


2010 ◽  
Vol 32 (3) ◽  
pp. 163-169 ◽  
Author(s):  
Camila Ribeiro de Souza ◽  
Osvaldo de Castro Ohlson ◽  
Melícia Ingredi Araújo Gavazza ◽  
Maristela Panobianco

Freshly harvested triticale seeds are usually dormant, making the immediate evaluation of the physiological potential of seed lots difficult. We evaluated different triphenyl tetrazolium chloride (TTC) test methods for rapidly determining the viability of four seed lots of x.Triticosecale Wittmack cultivar IPR111. The test variables were: Preconditioning, (i) placing whole seeds between moistened paper towels or (ii) directly soaking the seeds in water, both procedures being conducted at 20 ºC for 18 hours; Post-conditioning seed preparation, (i) longitudinal bisection of the seed through the embryo with one half being stained and the other discarded or (ii) longitudinal bisection with both halves being stained; Staining for three and four hours, in the dark, with 0.1%, 0.5% or 1.0% (w/v) TTC according to the preconditioning method described above, (i) both halves of each seed were placed on filter paper moistened with TTC and maintained at 40 ºC or (ii) one half of each seed was immersed in 5 mL of TTC solution in a 100 mL glass beaker at 30 ºC. The best results were obtained by preconditioning seeds between moistened paper towels at 20 ºC for 18 hours and staining on filter paper with 1.0% (w/v) TTC for three hours at 40 ºC.


2018 ◽  
Vol 5 (12) ◽  
pp. 181230 ◽  
Author(s):  
Yi-Xin Sun ◽  
Ying-Ying Wang ◽  
Bing-Bing Shen ◽  
Bi-Xian Zhang ◽  
Xiao-Mei Hu

A series of dicationic ionic liquids (ILs) including [C 4 (MIM) 2 ][PF 6 ] 2 , [C 5 (MIM) 2 ][PF 6 ] 2 , [C 6 (MIM) 2 ][PF 6 ] 2 and [C 4 (PYR) 2 ][PF 6 ] 2 were synthesized. Their thermal stability and melting points were analysed. It was found that dicationic ILs presented important implications in the design of homogeneous and heterogeneous system with water. A homogeneous system of dicationic ILs with water could be formed at a relatively high temperature and then a heterogeneous system was formed when the solution was cooled to a low temperature. The ILs recovered by altering the temperature were obtained in high percentage yields of [C 4 (MIM) 2 ][PF 6 ] 2 (97.6%), [C 5 (MIM) 2 ][PF 6 ] 2 (97.3%), [C 6 (MIM) 2 ][PF 6 ] 2 (98.0%) and [C 4 (PYR) 2 ][PF 6 ] 2 (94.2%). On the other hand, [C 4 (MIM) 2 ][PF 6 ] 2 and [C 5 (MIM) 2 ][PF 6 ] 2 exhibited good solubility in acetonitrile and acetone. A homogeneous system could be achieved with imidazolium-based ILs with a relatively low amount of water and acetonitrile at room temperature. All of the properties of dicationic ILs have a strong correlation with the nature of dications, the linkage chain and the symmetry of dications. Dicationic ILs may provide a new opportunity for some specific applications in order to enable the effective separation and isolation of products.


HortScience ◽  
1993 ◽  
Vol 28 (9) ◽  
pp. 899-901 ◽  
Author(s):  
Carlma B. Bratcher ◽  
John M. Dole ◽  
Janet C. Cole

The germination responses of wild blue indigo [Baptisia australis (L.) R. Br.], purple coneflower [Echinacea purpurea (L.) Moench.], Maximilian sunflower (Helianthus maximiliani Schrad.), spike goldenrod (Solidago petiolaris Ait.), and Missouri ironweed (Vernonia missurica Raf.) seeds after 0, 2, 4, 6, 8, or 10 weeks of stratification at 5C were investigated. Seed viability was determined using triphenyl tetrazolium chloride staining and germination based on the percentage of viable seeds. Germination percentage (GP) increased in all five species as weeks of stratification increased. Days to first germination and germination range (days from first to last germinating seed) decreased with increasing weeks of stratification, but the effect beyond 4 to 6 weeks was minimal. The number of weeks of stratification for maximum GP was 4 for purple coneflower, 6 for Maximilian sunflower, 8 for Missouri ironweed, and 10 for wild blue indigo and spike goldenrod.


Author(s):  
José R. Mondoñedo

The germinative capacity of coffee seeds may be evaluated within 2 days by using the following procedure: 1. The parchment is removed from a representative sample of coffee seeds and the seeds are soaked in water for an hour or more. Soaking for 24 hours is recommended for older and drier seeds. 2. The silverskin then is rubbed off, the seed rinsed, and kept in water ready for sectioning. 3. With a sharp blade, the seed is sectioned longitudinally through the embryo (slicing off a small portion of the cotyledons and radicle) which is imbedded in the endosperm but visible from the dorsal side. 4. The part with the larger section of the embryo is fully immersed for 16 to 24 hours in the TZ test solution (0.5 to 1.0 percent 2,3,5 triphenyl tetrazolium chloride in distilled water, adjusted to pH 5 to 7). 5. After immersion, the seed sections are rinsed and the embryo and endosperm examined carefully. Uniform red pigmentation on the embryo and endosperm indicates healthy viable seed. Pink or mottled coloration indicates weak seed of doubtful germinative capacity. White or no color change indicates dead seed. 6. Reading of results may be delayed several days by rinsing the treated seeds with water and storing them underwater at 8° to 10° C. It is recommended that more tests be conducted to determine more accurately the relationship between TZ test results and actual germination tests, especially those borderline cases exhibiting pink or mottled coloration. An easier method of exposing the uninjured whole embryo to the test solution could help in these cases. It also may be worth looking into a much longer duration of soaking before sectioning as this affects speed of reaction to the test, especially on older and drier seeds.


2014 ◽  
Vol 7 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Jeffrey R. Smith ◽  
Judith Hough-Goldstein ◽  
Ellen C. Lake

AbstractMile-a-minute weed or devil's tearthumb (Polygonum perfoliatum, syn. =Persicaria perfoliata) is an invasive annual vine in the Mid-Atlantic and Northeastern United States that reproduces solely through seeds. Our study aimed to identify how mile-a-minute seed viability is affected by time of year and the maturity of the fruit surrounding the achene. Full-sized immature (green) and mature (blue) fruits were collected from five field sites every 2 wk over a 3 mo period, and seed viability was assessed using a triphenyl tetrazolium chloride (TZ) assay. At the onset of seed production in mid-August, 35% of seeds from immature fruits were viable. This percentage increased steadily, peaking at 84% in late September before declining at some sites around the time of the first frost. In contrast nearly all seeds with mature fruits (96%) were viable at all collection dates. Thus land managers who apply physical or chemical control methods for mile-a-minute weed should do so before the onset of any seed production and not simply before fruit maturation. If it is necessary to apply control methods after fruit set, it should be done as early in the season as possible.


2020 ◽  
Vol 35 (1-2) ◽  
Author(s):  
Axay Bhuker ◽  
V. S. Mor ◽  
S. S. Jakhar ◽  
Puneeth Raj M. S.

Present study was conducted on four genotypes of quinoa to find out optimum temperature and method for germination test at Department of Seed Science and Technology, CCS HAU, Hisar during 2019-20. The result of this study revealed that at 25oC temperature average germination was 22.47 per cent while it was 13.31 per cent at 20oC temperature. Similarly seedling lengths were 9.69 and 7.58cm and seedling vigour index-I were 229.54 and 103.07 at 20 and 25oC respectively. Between the methods, Top of Paper (TP) recorded 19.78 % germination while Between Paper (BP) recorded 16.00 % germination. Similarly, 8.51 and 8.77cm seedling lengths and 157.83 and 174.78 vigour index-I were observed in Top of Paper and Between Paper methods respectively. Poor germination was recorded in all four genotypes (Maximum 42%) which was confirmed by conducting tetrazolium test. It is concluded from the study that 25 oC temperature and both Top of Paper and Between Paper methods can be used for germination test in quinoa crop. For radical emergence test, 250C temperature for 60 hours should be used and for seed viability test, the seeds should soaked into 1.0% percent tetrazolium solution (2, 3, 5-triphenyl tetrazolium chloride) for 20 hours at 30oC.


Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.


Alloy Digest ◽  
1960 ◽  
Vol 9 (7) ◽  

Abstract HAYNES STELLITE 98M2 Alloy is a cobalt-base alloy having higher compressive strength and higher hardness than all the other cobalt-base alloys at room temperature and in the red heat range. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as fracture toughness. It also includes information on heat treating, machining, and joining. Filing Code: Co-22. Producer or source: Haynes Stellite Company.


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