Optimum conversion to staminate flowering in hermaphroditic lines of pickling cucumber (Cucumis sativus L.) was obtained with 3 to 4 applications of 200-400 mg/liter of silver nitrate (AgNO3) at 4-day intervals, with initial treatment at the first true leaf stage.
Response of Toyonoka strawberry to AgNO3 was studied. Types and combinations of plant growth regulators had significant effects on shoot regeneration efficiency. Explants cultured for 10 days in shoot regeneration medium in the presence of AgNO3 not only enhanced shoot regeneration efficiency but also expedited the initiation of adventitious buds. Highest regeneration (87.38%) and number of shoots per explant (11.67) were achieved in shoot regeneration media containing 1.5 mg·L–1 TDZ, 0.4 mg·L–1 IBA and 1.0 mg·L–1 AgNO3. Half-strength MS containing 1.0 mg·L–1 AgNO3 was an optimum medium for rooting. AgNO3 advanced root emergence and increased percent rooting, root length, dry weight and activity. Lower concentrations of AgNO3 inhibited ethylene production and promoted shoot regeneration and growth. It had a significant stimulatory effect on chlorophyll, soluble protein contents and antioxidant enzyme activities. Chlorophyll and soluble protein contents, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities were increased in the presence of AgNO3 and reached maximum at 1.0 mg·L–1 AgNO3. Root water content, superoxide free radicals (O2 .-), malondialdehyde (MDA) content, proline accumulation and IAA-oxidase activity in leaves were increased while (IAA) content was decreased in the presence of AgNO3. Chemical names used: indole-3-butyric acid (IBA); silver nitrate (AgNO3); thidiazuron (TDZ); N6-benzyladenine (BA); 2,4-dichlorophenoxy acetic acid (2,4-D); indole-3-acetic acid (IAA); α-naphthalene acetic acid (NAA); gibberellic acid (GA3); bovine serum albumin (BSA); 2,3,5-triphenyl-2H-tetrazolium chloride (TTC).
Short pretreatments of stems of anthurium flowers (Anthurium andraeanum André) with silver nitrate solutions increased vase life by 40 to 60% after a simulated shipping. Significant improvement was obtained with a single 10-minute treatment with 1 mm silver nitrate. Maximum postharvest life was obtained with flowers treated with silver nitrate within 12 hours of harvest. Silver nitrate treatment was effective on flowers ranging from half to full maturity. No measurable silver was translocated to the spathe or spadix. Silver thiosulfate complex was not as effective as silver nitrate. For response to silver treatment following simulated shipping of 3 days, 2 cm of stem had to be removed before placing in a vase solution. Continuous maintenance of the flower before and after simulated shipping in a commercial preservative was not significantly better than a single pulse with silver nitrate or a combination of silver nitrate pulse and commercial preservative.
Cowpea (Vigna unguiculata L.) is an important grain legume that is grown extensively in Africa, South America, India, and in the United States. This study investigated the effects of silver nitrate (AgNO3) on regeneration of cowpea cotyledon explants. Silver nitrate at 50 μm significantly increased percent regeneration in comparison to the control. The effect of duration of exposure was also determined with the ethylene inhibitor AgNO3. By exposing explants to 59 μm AgNO3 during different stages of culture, significant increases were actualized in percent regeneration and shoot number. The greatest percent regeneration was obtained when 59 μm AgNO3 was augmented to both the initiation and regeneration media or to only the regeneration media. These results indicate that the low percentage of regeneration of this genotype may be related to ethylene biosynthesis or metabolism. This study resulted in an improved regeneration system for the commercial cowpea cultivar Early Scarlet, and will be useful in developing a cowpea transformation system.
Haploid (2x) roses derived from modern tetraploid breeding lines would allow for crosses to diploid species at the diploid level. In addition, inheritance studies are easier at the diploid level, using diploids derived from tetraploids possessing economically important traits. Haploidization of 4x roses through anther culture has not been successful due to challenges in callus induction and shoot regeneration. This study investigates rose anther responses to recently reported methods that optimize in vitro adventitious shoot regeneration in rose leaves. Anthers of three cultivars (Akito, Grand Gala, and Orlando) were put in a two-step callus induction (CI) and shoot regeneration procedure with varying CI factors. Experiment one (E1) compared continuous light/dark and silver nitrate (0,30,60 mg·L-1) and experiment two (E2) used the optimal E1 treatment comparing two and four weeks on CI media. Twenty-five anthers per treatment per cultivar were used in E1 and n = 100 for E2. Although no adventitious shoots were generated, callus formed on anther tissue and frequency of formation was variable across treatments. Continuous light resulted in 100% lethality. Darkness and silver nitrate (30 or 60 μm) favored callus generation and significant differences for callus generation were found among cultivars. Darkness and 30 μm silver nitrate were used in E2. Two and four weeks on initiation media were not significantly different for generation of anther-derived callus. Identification of factors which optimize callus formation on rose anthers is a positive step toward reliably generating rose haploids.
Silver nitrate and gibberellin A4/A7 (GA4/7) were compared for induction of staminate flower production on an inbred gynoecious cucumber (Cucumis sativus L.) line grown in the field at Madison, Wisconsin. Foliar sprays of silver nitrate at 100, 200, and 400 ppm induced significantly more staminate flowers per plant than did GA4/7 at the standard, widely-used rate of 50 ppm, making gynoecious x gynoecious hybrid seed production commercially feasible. The strong induction all plants treated with silver nitrate should minimize the genetic shift toward maleness observed from one generation to the next when GA is used to increase seed of gynoecious parental lines.
Sprays of silver nitrate (AgNO3), aminoethoxyvinylglycine (AVG) and gibberellins A4+7 (GA4+7) plus 6-benzylamino purine (BA) were applied with 0.1% Triton B-1956 at bloom to ‘Richared Delicious’ apple trees (Malus domestica Borkh.). AVG at 200 ppm alone or when applied with 50 ppm each of GA4+7 and BA increased fruit set whereas GA4+7 plus BA applied alone at 50 ppm caused fruit thinning. AVG reduced endogenous ethylene production and overcame the increased ethylene production brought about by GA4+7 plus BA application. AVG applied alone at 200 ppm or when combined with GA4+7 plus BA reduced fruit size and increased the L/D ratio at harvest.
( Catinot et al., 2008 ; Métraux et al., 1990 ). Silver nitrate (AgNO 3 ), an inhibitor of ethylene signal transduction, has been shown to improve in vitro plant regeneration ( Beyer, 1976 ; Chaudhuri and Kar, 2008 ; Kumar et al., 2007 ). Somatic
The effects of silver-containing compounds used for prolonging the vase life of cut rose (Rosa hybrida L. `Asami Red') flowers were investigated. Silver nitrate and RNA-Ag+tris (a ribonucleic acid-silver complex and trishydroxymethylaminomethane) increased the vase life by 2.7 days and prevented bent neck of cut rose flowers compared with the control, whereas silver thiosulfate (STS) did not have a significant effect on longevity. Fresh weights of the rose stems pretreated with silver nitrate or RNA-Ag+tris were maintained along with longer vase life. There were higher amounts of Ag+ in the basal parts of the stem in these treatments compared with STS treatment. Bacterial count at the cut surface of stems treated with either silver nitrate or RNA-Ag+tris were lower than STS-treated or control stems. These results indicated that the primary effect of silver-containing compounds on `Asami Red' roses was antimicrobial.
Species of Alternaria and Gloeosporium were most often isolated from fruit with blossom-end yellowing (BEY), a disorder associated with summer fruit drop of navel orange [Citrus sinensis (L.) Osbeck]. Fruit inoculated with pure cultures of these fungi did not develop BEY; however, wounded fruit which were inoculated with fungi produced higher levels of ethylene and more extensive BEY than wounded, noninoculated fruit. Fruit with BEY produced higher amounts of ethylene than symptomless fruit. The methoxy analog of rhizobitoxine (methoxyvinylglycine) did not reduce ethylene levels, and silver nitrate increased ethylene production from fruit with BEY. Ethylene and fungi are associated with BEY of navel orange but do not appear to be causal factors.
