A seasonal study was conducted to assess the freezing injury of `Boskoop Giant' black currant (Ribes nigrum L.) samples from Oct. 1991 through Mar. 1992. Buds were subjected to either differential thermal analysis (DTA) or one of a series of temperatures (0 to -36C). Freeze injury was then assessed either visually or with TTC. Results indicated that black currant floral buds have multiple low-temperature exotherms (LTE). Freeze injury in intact buds could not be visually quantified because of the lack of visible browning, nor assayed with TTC reduction. Excised floral primordia incubated in TTC, however, developed colored formazan following exposure to nonfreezing and sublethal freezing temperatures, but remained colorless when exposed to lethal temperatures. The percentage of floral primordia that were colored and colorless were tabulated and a modified Spearman-Karber equation was used to calculate the temperature at which 50% of floral primordia were killed (T50 The T50 temperature was correlated with the temperature at which the lowest LTE was detected (R2 = 0.62). TTC reduction assay using excised floral bud primordia was a good indicator of viability in frozen blackcurrant buds. Chemical name used: 2,3,5-triphenyltetrazolium chloride (TTC).
measured. Relative EL (Rt) was calculated as Rt (%) = (EC1/EC2) × 100. TTC test. One 1-cm-long section was cut from the apical, middle, and basal parts of each shoot, and placed in a tube, to which 10 mL 0.5% 2,3,5-triphenyltetrazolium chloride (TTC) was
opened for removing seed samples, bar = 2 cm. ( B ) 2,3,5-Triphenyltetrazolium chloride (TTC)–positive red coloration of viable seeds observed under a stereomicroscope (4×), bar = 1 mm. ( C ) In vitro seed germination and protocorm development (90 d after
( n = 3). The effects of PGRs on root 2,3,5-triphenyltetrazolium chloride-reducing activity under suboptimal temperature stress. As shown in Fig. 5 , under normal conditions (day 0), the root TTC-reducing activity in ‘Zhongshu6’ was similar to that
2,3,5-Triphenyltetrazolium chloride (TTC) reduction measures glucose equivalents of substances diffusing from plant tissues. Amounts of diffusing substances are greater from cold-hardened than unhardened citrus. These differences are colorimetrically distinguishable and identify citrus plants exposed to low temp in controlled environment studies.
. (2009 ), we used 0.5% triphenyltetrazolium chloride (TTC) buffer solution and a culture medium (10 g·L −1 agar + 0.1 g·L −1 boric acid + 100 g·L −1 sucrose solution) combined with the in vitro germination method to detect the pollen vitality
Ethylene and ethane production of freeze-stressed rhododendron (Rhododendron sp. ‘Sappho’) leaf disks were compared to visual rating, TTC reduction, and electrolyte leakage as possible means of measuring tissue viability. Ethane production, as caused by freezing temperatures, was highly correlated with visual rating, TTC reduction, and electrical conductivity (r = 0.96, r = −0.81, and r = 0.96, respectively). Ethylene production peaked concurrently with initial stages of visual tissue damage, then decreased as the temperature was lowered until complete death occured. Ethane production and electrolyte leakage peaked coincidentally with the decrease of ethylene. Ethylene:ethane ratios are suggested as a measurement of freeze-induced tissue damage. This study supports the view that ethylene production is related to stress and ethane production to cell death. Chemical names used: 2,3,5-triphenyltetrazolium chloride (TTC).
Roots of one year old grape cvs. Concord, White Riesling, Grenache and Semillon were frozen to 0, -5, -10, -15 and -20°C in a programmable freezer. The tops were protected from cold by insulating them. For survival test, 4 plants of each cv. were planted in the greenhouse and their growth observed. Differential thermal analysis (DTA), using a computer attached to a programmable freezer was performed on roots. To aid in the interpretation of DTA, triphenyltetrazolium chloride (TTC) was performed. Hardiness determinations were based on DTA, TTC and the survival tests. DTA patterns representing exothermic response showed an exotherm associated with extracellular free water in tissue which appeared at about the same temperature range for all cvs. This is not associated with hardiness. Additional minor exotherms related to hardiness appeared at lower temperatures than the extracellular water exotherm. Their location differed from one cv. to another. Based on these tests, Concord roots appear to be hardier than other cvs. with important but minor differences in the hardiness of other cvs.
`Danka' black currant floral buds produce multiple low temperature exotherms (LTEs). However, the absence of visual injury symbtoms in the buds after exposure to subfreezing temperatures make it difficult to assess injury in these buds. A 2,3,5-triphenyltetrazolium chloride (TTC) reduction assay was used to determine whether LTEs corresponded to freezing injury of individual floral primordia or to the entire floral axis. Intact buds were cooled at 3C/n, removed at 3C intervals from -12 to -33C, and thawed on ice for 24 h. Duplicate samples were subjected to differential thermal analysis. Freeze injury Could not be measured with TTC in thawed, intact buds. However, incubation of excised floral primordia in TTC resulted in an all or nothing response. The number of LTES did not correspond to the number of floral primordia killed within a floral bud, but the median LTE did correspond with the temperature at which lethal injury of the whole inflorescence occurred. Therefore, preliminary results indicate that TTC reduction assay of individual floral buds is a fast, reliable technique to assess bud injury.
Samples of current season shoots of Anjou, Bartlett and Bosc pears were collected throughout the year during 1990, `91 and `92. Differential thermal analysis (DTA) and vital staining with triphenyltetrazolium chloride (TTC) were used at the sampling times to determine freeze resistance. Freezing tests were conducted on greenhouse-grown trees. Temperatures to freeze the trees were predetermined by DTA. After freezing TTC staining, acid fuchsin test and growth were used to determine survival. All three varieties began to acclimate after terminal growth ceased in late June until October. Bartlett and Anjou obtained about -25°C resistance by this time and Bose about -23°C. After frost began, Anjou and Bartlett gained an additional resistance to -33°C and Bose to -28°C. Trees frozen artificially at -27°C had limited growth but did leaf out only to die a month later. Trees frozen at -33°C never leafed out Bartlett trees at -27°C looked better than Anjou and Bose trees but died also.