الفهرس 
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Abstract
INTRODUCTION: Sunflower (Helianthus annuus, L.) as a cut flower has been increasing in economic importance in the floral industry. However, their vase life is short. The vase life of sunflowers varies between 4-13 days depending on cultivar and is terminated by symptoms such as scape bending, abscission and wilting of ray flowers (Kılıç et al., 2020). Solidago (Solidago canadensis, L.) is an excellent cut flower commonly used for indoor decoration in vases, bowls and as a dried flower. Demand for solidago has been dramatically over the past years, it is a new crop among the top 25 most popular cut flowers around the world (Taha et al., 2015). MATERIALS AND METHODS: The cut flowers used for this investigation were brought from a well-known commercial nursery in El-Qanater, El-Qaluobiya Governorate, Egypt, (Tabaraq nursery) at 23 and 19 June during both seasons, respectively. Cut flowers were cut in the early morning, potted in icebox collar and were transported under controlled environment conditions to the control vase life room during about 3 hours. The holding solutions for sunflower were fortified with 10% sucrose, while the holding solutions for solidago were fortified with 2% sucrose. The holding solutions treatments could be summarized as follows: • Control (Distilled water). • Silver nitrate at 30 ppm for sunflower and 10 ppm for solidago. • Neem at 2.0, 1.0 and 0.5%. • Oleander at 2.0, 1.0 and 0.5%. • Guava at 2.0, 1.0 and 0.5%. Part 1: postharvest parameters in sunflower cut inflorescences. A- Impact of silver nitrate and some natural extracts on cut inflorescences of sunflower postharvest characteristics. 1. The longest vase life was obtained from sunflower inflorescences which held in vase solution fortified with 1.0% neem extract, 1.0% oleander extract and 0.5% guava extract each separately plus 10% sucrose (11.00 days for each) in both seasons of the study. 2. Change in fresh weights of sunflower from cut inflorescences held in solution with 1.0% neem extract, 1.0% oleander extract, and 2.0% guava extract vase solution, increased until the eleventh day (final day of vase life) in both seasons compared to other treatments of study. 3. Preservative solution supplemented with 1.0% from oleander, neem or guava extracts resulted in the highest value of maximum increase in fresh weights (11.53 and 12.45%), (9.29 and 9.50%), (9.15 and 9.58%), respectively among other treatments in both seasons. 4. Holding solutions of 30 ppm silver nitrate, 1.0 or 0.5% of neem extract, 1.0% of oleander extract and 1.0% guava extract increased percentage of relative fresh weight percentages (RFW) until the seventh day in both seasons. 5. Maximum total water uptakes were obtained from cut inflorescences which held in 1.0% oleander or neem extracts, as they recorded the highest values (143.67 and 149.67 g/inflorescence) (129.67 and 145.33 g/inflorescence), in both seasons, respectively. Besides, 30 ppm silver nitrate preservative solution, still give higher total water uptake values comparing with the control. 6. Preservative solutions contained 1.0% oleander or neem extracts and 0.5% guava extract still gave higher values in change in water uptake (g/100g F.W./2days) until the last day (11th day) of experiment in both seasons, as well as 0.5% neem in the second season. However, change in water uptake of sunflower cut inflorescences was not recorded significant differences between most of the holding solutions in both seasons until the seventh day of experiment. 7. Change in water loss had no significant differences between most of preservative solutions and the control in both seasons until the fifth day of shelf-life. However, the control started to record higher water loss values from the fifth day until the seventh day of its shelf-life comparing with all the other preservative solutions. 8. Comparing with the control, all concentrations of the natural extracts and silver nitrate (30 ppm) significantly improved the water balance after the first three days until the seventh day in most of cases and after that a slight decrease in water balance values began until the end of shelf-life period in both seasons. 9. Sunflower inflorescences diameter was not recorded significant differences between all holding solutions in both seasons of study. But treatments of neem extract at 2.0 or 1.0% and oleander extract at 0.5%, followed by silver nitrate at 30 ppm still recording higher values of this parameter. B- Impact of silver nitrate and some natural extracts on cut inflorescences of sunflower chemical characteristics. 1. Cut inflorescences which held in preservative solution fortified with 2.0% guava extract recorded the highest values of chl. a, b and a+b (0.648, 0.359 and 1.041 mg/g F.W., respectively) during the first seasons. Neem extract at 2.0% came in the second order (0.610, 0.340 and 1.000 mg/g F.W.), then 2.0% of oleander extract (0.530, 0.306 and 0.869 mg/g F.W.). Data in second season gave a similar trend. 2. The highest values of carotenoids content in leaves (0.099 and 0.111 mg/g F.W., respectively in both seasons) resulted from the use of silver nitrate at 30 ppm. While the lowest values (0.050 mg/g F.W.) recorded from neem extract at 1.0% in the first season and 0.054 mg/g F.W. from oleander extract at 1.0 % in the second season. 3. Cut inflorescences held in preservative solutions containing 2.0% of guava extract had significantly an increase effect in carotenoids content of flowers compared to control (70.0% and 72.5, respectively in both seasons), Followed by 2.0% of neem extract (57.5 and 65.0%, respectively in both seasons). While the lowest value of this character was recorded in the control flowers (0.040 mg/g F.W. in both seasons). On the other hand, no significant difference between treatments of silver nitrate (30 ppm) or neem and oleander extract at 0.5% comparing with the control in this character. 4. Maximum values of total sugar in cut inflorescence leaves resulted when using preservative solution contained 2.0% guava extract (7.06 and 7.44 %D.W.) in both seasons, respectively. Followed by using a preservative solution contained 2.0% neem extract (6.91 and 7.24 %D.W.) and a preservative solution contained 30 ppm silver nitrate (6.78 and 7.04 %D.W.) in both seasons, respectively. 5. Sunflower cut inflorescences held in solution contained 2.0% guava extract gave the highest values of N, P and K % (4.23 % N), (0.81 %P) and (4.01 % K) followed by 2.0% neem extract (4.16 % N), (0.80 % P) and (3.97 % K), respectively. Also, sunflower treated with silver nitrate gave high values of N, P and K % (4.12 % N), (0.77 % P) and (3.83 % K). B- Impact of silver nitrate and some natural extracts on cut inflorescences of sunflower microbial growth. 1. Holding solution containing sucrose solely (control) recorded the highest bacterial count (800.00 and 1056.00 x102 cfu/ml), respectively in both seasons compared with all the other treatments. On the other side, preservative solution which contained silver nitrate was free from any bacterial count, followed by rest of the other treatments. Part 2: postharvest parameters in solidago cut spikes. A- Impact of silver nitrate and some natural extracts on cut spikes of solidago postharvest characteristics. 1. The longest vase life was obtained from solidago spikes which held in vase solution fortified with 2.0% neem extract or 0.5% oleander extracts each separately plus 2.0% sucrose for any of them (15.00 days). On the other hand, treatments of 1.0% neem or oleander extracts, guava extract at 2.0% or 1.0% and 0.5% also tabulated a longer vase life values and there were no significant between them and the previous superior treatments in both seasons. 2. Change in fresh weights of solidago cut spikes which held in the preservative solutions with all-natural extracts in any concentration recorded highest values for this parameter in both seasons of study compared to control. 3. Highest value of maximum increase in fresh weight obtained from spikes which held in solutions supplemented with 0.5% oleander extract, followed by 2.0% neem extract among other treatments in the first seasons.4. The highest percentages of RFW were obtained with oleander extract at 0.5% compared with control. On the other hand, cut spikes held in a preservative solution containing 10 ppm of silver nitrate gave good results for this characteristic until the end of their life (13th day) during both seasons. 5. Total of water uptake (g) for most treated solidago cut spikes with different preservative solutions was higher in both seasons than control treatment. Moreover, in both seasons it was clear that adding 10 ppm silver nitrate, 2.0% or 1.0% neem extract, 0.5% oleander extract and 2.0% guava extract recorded higher total water uptake values compared with control and some other treatments. 6. Holding solutions which fortified with 10 ppm silver nitrate, 2.0% neem extract, 0.5% oleander extract and 2.0% guava extract significantly improved change in water uptake during both seasons comparing with most of the other cases during the shelf-life. Although, the control especially in the first season gained high change in water uptake, but a sharp decrease in values of that parameter were shown during the shelf-life period more than most of the natural preservative solutions under study or the silver nitrate treatment. 7. Oleander extract at 0.5%, neem extract at 2.0% and guava extract at 2.0% in both seasons, maintained stable water loss values than most of other treatments until the final day of shelf-life. Moreover, the use of 10 ppm silver nitrate recorded high values for this trait, until the death of its spikes at 13th day. In addition, the control represented the highest water loss values from the first day during the shelf-life in season one comparing to most treatments. 8. Cut spikes held in most concentrations of natural extracts under study or silver nitrate at 10 ppm maintained higher water balance values compared with control until the eleventh and thirteenth days (the death days of cut spikes held in control treatment), respectively in both seasons. B- Impact of silver nitrate and some natural extracts on cut spikes of solidago chemical characteristics. 1. Holding solidago cut spikes in solutions fortified with 2.0% neem or guava extracts gave the maximum values of chl. a, chl. b and a+b contents (0.645, 0.398 and 1.043 mg/g F.W.) and (0.637, 0.401 and 1.038 mg/g F.W.), respectively in both seasons. Also, cut spikes which held in preservative solution contained 2.0% oleander extract produced higher values of chl. a, chl. b and a+b in second season than control and most other treatments (0.637, 0.390 and 1.027 mg/g F.W.), respectively. 2. Highest values of leaves carotenoids content (0.204 and 0.203 mg/g F.W.), respectively in both seasons resulted from cut spikes which held in preservative solution supplemented with guava extracts at 2.0%. Followed by spikes which held in preservative solutions contained neem extracts at 2.0% (0.194 g/mg F.W.). 3. Most concentrations of natural extracts increased total sugars content in leaves of solidago cut spikes when compared with control and silver nitrate at 10 ppm. where cut spikes held in preservative solutions containing 2.0% of guava extracts had significantly an increase effect compared with other treatments. The least values (12.98 and 13.40 % D.W.) resulted from the control in both seasons, respectively. 4. Solidago cut spikes which held in preservative solution contained 2.0% guava extract gave the highest values of N, P and K % (3.73 % N), (0.79 % P) and (3.63 % K), followed by 2.0% neem extract (3.62 % N), (0.78 % P) and (3.55 % K). Also, cut spikes which held in preservative solution of 10 ppm silver nitrate gave high values (3.67 % N) and (3.54 % K) compared with control. B- Impact of silver nitrate and some natural extracts on cut spikes of solidago microbial growth. 1. Holding solution containing sucrose solely (control) recorded the highest bacterial count (3540.00 and 2880.00 ×102cfu/ml), respectively in both seasons compared with all concentrations of natural extracts and silver nitrate at 10 ppm treatments. In conclusion, this study demonstrated the potential influence of ethanolic natural extracts of neem, oleander and guava leaf as floral preservatives on the postharvest longevity and quality characteristics of cut sunflower and solidago stems. Continuous use of preservative solutions containing 1.0% neem or oleander and 0.5% guava leaf extract plus 10.0% sucrose led to the best postharvest ornamental qualities on cut sunflower inflorescences. For cut spikes of solidago, continuous treatment with 2.0% neem or guava and 0.5% oleander plus 2.0% sucrose proved to be the best preservative solutions. These applications may be developed to suit the intended use by consumers as safe and biodegradable alternatives to chemical preservatives, being extend tested species vase life and keeping quality. Sunflower, Solidago, Postharvest, Vase life, Water relationships, Natural extracts.