Effect of seed age,stratification, and soaking on germination of wild asparagus (Asparagus acutifolius L.)

Wild asparagus (Asparagus acutifolius L.) is a widespread species found in all the Mediterranean areas. The spears are highly valued by consumers and owing to its frugality, this species is a feasible new crop with high income potential, especially for Mediterranean marginal areas. Currently, the cultivation of this species is limited because of its low and erratic seed germination that makes difficult the production of seedlings for plant propagation. In this research, non-after-ripened (1 month-old) and after-ripened seeds (dry stored at room temperature for 13 months) were exposed for 30 days in the dark to three moist stratification treatments: cold (5 °C), warm (23 °C) or no stratification; subsequently they were soaked for 12 h in warm water (35 °C) or not soaked. The effect of these pre-germination treatments on three germination parameters (germination percentage, time to 50% of final germination – T₅₀ – and germination pattern) was studied, as well as some possible seed dormancy forms involved therein. The 1-year dry storage period proved to be effective in after-ripened seeds by enhancing seed sensitivity to the subsequent pre-germination treatments. After-ripened seeds exhibited higher and more rapid germination compared to non-after-ripened seeds. Soaking, cold or warm moist stratification had similar single effect on non-after-ripened seeds (27% germination). With after-ripened seeds, only soaking or warm stratification were effective (47% germination) when singularly applied, while cold stratification did not improve germination. By combining stratification and soaking treatments, a higher germination for both non-after-ripened and after-ripened seed-lots was achieved. The highest germination was obtained when after-ripened seeds were stratified and soaked (76%), without any significant difference between cold or warm stratification. Single or combined application of moist stratification (regardless of the temperature used) and soaking resulted always in a faster germination compared to that of no-treated seeds and especially with after-ripened seeds (T₅₀ = 6 days). A non-deep type 1 physiological dormancy can be hypothesized for the seeds of this species. Low stratification temperature induce secondary dormancy in after-ripened seeds that can be removed by soaking them at 35 °C for 12 h.     

Biocontrol of mildew with Bacillus subtilis in bitter gourd (Momordica charantia L.) seeds during germination

The bitter gourd seed has a thick, hard seed coat. Mildew often occurs during germination and causes uneven and low rates of seed germination. However, the problems caused by mildew can be overcome by treating seeds with hot water, by soaking in water, or by using microorganisms. Seeds of the ‘Ching Pi’ bitter gourd were treated in a water bath at 60 °C for 10 min and then soaked in tap water at 25 °C for 24 h. The resulting germination percentage was 86.7%, and the resulting percentage of mildewed seeds was 10%. The biocontrol potential of three commercially available Bacillus subtilis solutions was examined. For seeds primed with Huodijun B. subtilis solution, the germination percentage was 73.3% and the mildewed percentage 6%. In dual cultures, the antibiotic content in the Huodijun B. subtilis solution was significantly greater than in Yunghsing and Huolibao, the other B. subtilis solutions examined. B. subtilis effectively inhibited the growth of Rhizoctonia solani mycelium and caused abnormal mycelial growth.     

Seed dormancy and germination of Michelia yunnanensis (Magnoliaceae)

Michelia yunnanensis Franch. is a Chinese endemic ornamental shrub with potential for greater utilization as a landscape and medicinal plant if propagation was less difficult. Seed development and breaking of seed dormancy were investigated to improve propagation of M. yunnanensis. No fresh seeds germinated when tested at the time of dispersal. Newly matured seeds of M. yunnanensis contained differentiated linear underdeveloped embryos that were physiologically dormant. The embryo/seed length ratio of M. yunnanensis was 0.15. Warm stratification did not break seed dormancy. Dormancy was broken by cold stratification at 4 °C but not by flowing water or nitrate. Embryos developed grew inside seeds during cold stratification at 4 °C. In newly harvested dormant seeds, embryos were 0.94 mm long and increased in length 139% before radicle emergence (germination). GA₃ substituted for cold stratification to break dormancy in seeds of M. yunnanensis incubated at 25 °C or 20/25 °C. Mature M. yunnanensis seeds exhibited intermediate complex morphophysiological dormancy. Optimal germination of non-dormant seed in terms of both germination percentage and rate occurred at 20/25 °C.     

赤霉酸处理对核桃种子萌发和幼苗生长的影响

为了提高核桃种子的发芽率和幼苗生长量,用不同浓度赤霉酸处理核桃种子后,研究了不同浓度赤霉酸处理对核桃种子出苗期、发芽率和种子播种后幼苗生长量的影响.结果 表明:不同浓度赤霉酸处理核桃种子后,均提早了出苗始期、出苗高峰期、出苗终期,缩短了出苗周期,提高了发芽率和幼苗株高、地径、根长,促进了枝条木质化和顶芽饱满程度.不同处...     

The effect of gibberellic acid (GA3) on some phenolic substances in globe artichoke (Cynara cardunculus var. scolymus (L.) Fiori)

Globe artichoke has important nutritional values related to its high content of phenolic compounds such as cynarin and chlorogenic acid. Cynarin (1,5-dicaffeoylquinic acid) is a derivative of caffeic acid and has effect on hepatobiliary diseases, hyperlipidaemia, dropsy, rheumatism and cholesterol metabolism. The effect of gibberellic acid (GA₃) on the yield of the phenolics, chlorogenic acid and cynarin, both in leaves and in the edible part of the head of globe artichoke, were studied. Plant samples were collected for chemical analyses at the laboratories of the Chair of Vegetable Science, Department for Plant Sciences, Technische Universität München in Freising-Weihenstephan, Germany. GA₃ at 60 ppm was applied either at 4, 6 or 8 weeks after transplanting date (ATD). When transplant were used, application of GA₃ at 4 weeks ATD significantly increased the content of chlorogenic acid in leaves while the level of cynarin was similar to the untreated control. In contrast when plants were direct seeded into the field, GA₃ treatments had no affect on phenolics in leaves compared to the untreated control. Whereas GA₃ reduced the time to flowering, it did not increase the content of chlorogenic acid or cynarin in leaves or in most of the flower receptacles, except when GA₃ was applied at 6 or 8 weeks. On the other hand, cynarin yield in the 3rd–5th harvested flower heads was higher than controls. The timing of GA₃ application is, thus, critical for decreasing time to flower as well as altering the content of cynarin and chlorogenic acid in globe artichoke.     

Relationship between changes in endogenous polyamines and seed quality during development of sh2 sweet corn (Zea mays L.) seed

Polyamines putatively affect tolerance to abiotic stresses and are believed to be important in organogenesis. Present experiments investigate the relationship between polyamines (PAs) and seed quality. Therefore, during seed development, the changes in free putrescine (Put), spermidine (Spd) and spermine (Spm) and physiological and biochemical parameters in F₁ seeds of sh₂ sweet corn were compared. Concentrations of Put, Spd and Spm increased from 14 to 30 days after pollination (DAP). After 30 DAP Put concentration declined with an opposite trend to that of Spd and Spm. The regression analysis between PAs and seed quality described by physiological and biochemical parameters including germination percentage, germination energy, germination index, seed size, seed fresh and dry weight, total soluble sugar, total soluble protein, Malondialdehyde (MDA) concentration, electrolyte leakage, peroxidase (POD) and catalase (CAT) activity were conducted. Spd was observed to have a closer relation with the comprehensive physiological changes of seeds during their development than that of Put and Spm. Moreover, the Spm concentration might be more suitable to forecast seed germinability during seed maturation period than Spd and Put. It indicated that endogenous Spd and Spm in dissociated form had more effect than Put during seed development progress of sweet corn.     

Effects of ethephon,GA3 and nutrient elements on sex expression of Chinese chestnut

The effects of ethephon or GA₃ on sex expression of Chinese chestnut (Castanea mollissima BL.) were opposite to the effects of these plant growth regulators on cucumber, pumpkin and Chinese white-flowered gourd. Ethephon at 100–500 mg 1^?1 inhibited the development of female flowers and promoted that of male flowers. GA₃ at 50–500 mg 1^?1 caused a significantly lower number of male inflorescences, but increased the number of female flowers. Urea applications decreased the number of male inflorescences and increased the number of female flowers. For plants grown on phosphorous-deficient soils, fertilizing with superphosphate also increased the number of female flowers. Spraying trees with GA₃, urea or a mixture of both increased the number of female flowers. Therefore, it is proposed that such applications should be employed at the onset of differentiation of flower primordia of Chinese chestnut to increase the ratio of female to male flowers.     

Horticultural factors regulating effectiveness of GA3 inhibiting flowering in peaches and nectarines (Prunus persica L. Batsch)

The application of gibberellic acid during the flower bud induction period significantly reduced flowering in peaches and nectarines. The magnitude of the response significantly depended on the total amount of active material applied per tree. Results show, for cultivars tested, a higher sensitivity of peach to GA₃ in comparison with nectarine. Concentrations of 0.5 or 1.0 g tree⁻¹ of gibberellic acid reduce flowering by about 50% in both, peaches and nectarines, respectively, and it gives rise to a reduction of costs of hand thinning by 50%, approximately, without affecting the yield. Fruit colour advanced, total soluble solids concentration increased and fruit firmness increased as a consequence of treatments. The effect was higher in the basal part of the shoots and reduced from the base to the apical part.     

Effect of GA3, CCC defoliation and quantum flux density on growth and flowering in Pelargonium × hortorum

In vegetatively propagated Pelargonium × hortorum plants, formation of axillary shoots and initiation of inflorescences and leaves were promoted by an increase in quantum flux density, whereas application of GA₃ had a negative effect. Application of CCC caused an increase in number of axillary shoots and consequently an increase in number of inflorescences and leaves per plant.Dry weight increase was promoted by an increase in quantum flux density, unaffected by GA₃ treatment, but inhibited by CCC treatment. Moreover, continuous removal of the oldest leaves reduced the number of inflorescences, leaves, axillary shoots and dry weight. The changes in inflorescence and leaf initiation could not be definitely correlated to the changes in dry weight increase.     

Germination of Passiflora mollissima (Kunth) L.H.Bailey, Passiflora tricuspis Mast. and Passiflora nov sp. seeds

Passiflora mollissima, Passiflora tricuspis and Passiflora nov sp. are three passion fruit species occurring in Bolivia. Germination percentages and rates were determined for 11 different treatments. Per species, germination of 100 seeds was monitored every 3 days, during 90 days. Germination started after 9 days and 50% of final germination was reached within a month or less. Successful, recommended methods for P. mollissima are removing the basal point of seeds (27% germination) or removing the basal point in combination with pre-soaking seeds for 48 h in 50 ppm GA₃ (18%). Pre-soaking seeds for 24 h in 400 ppm GA₃ (42%) and removal of the basal point in combination with pre-soaking seeds for 48 h in 50 ppm GA₃ (36%) are suggested methods to improve germination of P. nov sp. Removing the apical point of P. tricuspis seeds resulted in maximal germination (57%). No unique treatment gave satisfactory results for the three species tested. Exogenous dormancy, probably a combination of mechanical and chemical dormancy is present in the three species studied. Presence of physical dormancy was found in P. mollissima.     

Effects of seed maturity,seed storage and pre-germination treatments on seed germination of cleome (Cleome gynandra L.)

The influence of seed maturity, seed storage and germination pre-treatments on seed germination of cleome (Cleome gynandra L.) were investigated. Seed maturation studies showed that capsules harvested at 18 days after anthesis possessed the highest dry weight with 19.2% moisture and 1% germination. Development of fresh-ungerminated seed was observed with increasing maturity of fruit, suggesting that cleome exhibited forms of seed dormancy. Storing mature seed at 15 °C and at room temperature for 5 months showed that seed dormancy was broken after 3 months under both storage regimes. When mature seeds were subjected to different treatments including various levels of GA₃, KNO₃, leaching, pre-chilling, soaking and pre-heating at different temperatures, it was found that pre-heating at 40 °C for period of 1–5 days was the most effective method in breaking dormancy in cleome.     

Effects of cadmium and copper on pollen germination and fruit set in pea (Pisum sativum L.)

In this work, pea (Pisum sativum) plants exposed to increasing cadmium and copper concentrations were tested for heavy metals accumulation in flowers and for ‘in vivo’ pollen germination. Based on the Cd and Cu accumulation amounts in the flowers, an evaluation of the same metals effects on ‘in vitro’ pollen germination was achieved. Moreover, the effects of both metals on fruits number and weight and on seed set and yield at individual plant level were examined. While cadmium concentrations did not affect ‘in vivo’ pollen germination, only higher copper concentrations rendered a significant reduction. This is in contrast with the clear negative effect on pollen germination in vitro and might be explained by the different dynamic and bioavailability of both metals. A clear effect of Cd and Cu was observed on two important yield components ie, fruit weight and seed set. Although results obtained herein cannot give a clear cut relationship between the effect of Ca and Cu on reproductive development and its consequences on yields, they represent emerging results on the potential consequences of metals contamination on reproductive development in plants.     

The effects of GA3, CCC and B-9 upon growth,development and organic compounds in Primula obconica

GA₃ induced stem elongation and had no effect on leaf area, whereas CCC and B-9 reduced those characteristics. All 3 growth substances increased leaf formation. GA₃ and CCC accelerated the beginning and duration of blooming, but B-9 exhibited the opposite trend. Inflorescence formation was promoted by CCC and B-9 and decreased by GA₃. Stalk length of inflorescences was elongated only by GA₃ and dwarfed by CCC and B-9. Carbohydrate fractions and content of anthocyanin in flowers were promoted by CCC and B-9.     

芥菜类蔬菜种子休眠破除技术的研究

采用常温、低温和变温处理的方法对5个芥菜变种开展了种子休眠敏感性试验,试验结果表明,在各芥菜变种材料开花期和采收期一致的情况下,以芥菜完成后熟(2017年采收)的种子为对照(CK),常温下进行种子发芽率测试,结球芥菜、茎瘤芥菜和大头菜无休眠现象,大叶芥菜17W170与分蘖芥菜17W306与各自对照间有显著差异;具休眠现象的芥菜种子,低温3 d处理及干燥种子变温处理可明显提高芥菜类种子发芽率。因此,芥菜类蔬菜不同变种存在不同程度的休眠,而低温和变温处理是打破芥菜类蔬菜种子休眠的实际有效方法。     

The effect of chlormequat chloride (CCC) application at the bolting stage on the flowering and seed production of lettuce plants previously treated with water or gibberellic acid (GA3)

Lettuce plants were sprayed with gibberellin (GA₃) or water at the rosette (8-leaf) stage and subsequently with water or CCC (500 or 1500 ppm) at the onset of bolting. GA₃ induced rapid bolting and increased seed yield, but seed stalks were longer and thinner than those that had been sprayed with water at the same stage. Treatment with CCC (500 ppm) at bolting decreased the flower stalk height of plants that had been sprayed with water at the rosette stage, but not that of GA₃ treated plants. CCC (500 ppm) increased the number of inflorescence branches per plant as well as seed yield in the autumn sown crop, but had no effect on the winter sown crop. When a higher concentration of CCC (1500 ppm) was applied at bolting, flower stalk height decreased, irrespective of whether the plants had been previously treated with GA₃ or not, and seed stalk diameter increased. However, 1500 ppm CCC reduced the number of inflorescence branches per plant and mean seed yield. It is concluded therefore that although the application of 500 ppm CCC at the onset of bolting may increase seed yield in the autumn sown crop, this treatment does not improve the seed stalk strength (e.g. increasing diameter or reducing height) of GA₃ treated plants. On the other hand, whereas a higher concentration of CCC (1500 ppm) improves seed stalk characteristics, it reduces seed yield.     

UV-B增强下6-BA、GA_3对油桃光合和抗氧化酶活性的影响

【目的】为探讨UV-B增强下植物生长调节剂对油桃光合作用的调控,【方法】以‘中油桃8号’为试材,研究了叶面喷施6-BA和GA3对UV-B增强下油桃光合特性和抗氧化酶活性的影响。【结果】结果表明,补充15μW.cm-2的UV-B辐射后,油桃的净光合速率下降,叶绿素a含量增加;补充30μW.cm-2的UV-B辐射,净光合速率和叶绿素a含量受到明显抑制,叶绿素b略有下降。喷施50 mg.L-16-BA和GA3可有效提高UV-B增强下叶片的Pn和叶绿素a、b含量。50 mg.L-16-BA处理14 d后,UV-B增强下叶片的SOD、POD活性明显上升,MDA含量显著下降,类黄酮含量与对照无显著差异;而GA3处理则提高了叶片的类黄酮含量,但MDA和抗氧化酶活性无显著变化。【结论】UV-B辐射增强下,6-BA对油桃光合特性的促进可能与SOD等抗氧化酶活性的提高有关。     

Effects of proline on antioxidant system in leaves of grapevine (Vitis vinifera L.) exposed to oxidative stress by H2O2

Although proline is one of the major computable organic solutes that accumulate in many plant species in abiotic stresses, a hot debate continues about whether proline accumulation is a reaction to abiotic stress, or a plant's response is associated with stress tolerance. The effects of proline on antioxidative system in grape leaves of Vitis vinifera L. cv., ‘Öküzgözü’ exposed to oxidative stress by H₂O₂ was investigated. Endogenous proline, hydrogen peroxide (H₂O₂), malondialdehyde (MDA) concentrations, percentage of electrolyte leakage (EL), and some of the antioxidant enzyme activities; such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (POD) were measured spectrophotometrically. Inhibitory effect of H₂O₂ on antioxidant enzyme activities, MDA, and EL was found. In the presence of proline, SOD and CAT activities decreased, while POD and APX activities increased. Proline pre-treatment resulted in a decrease in cellular H₂O₂ content, MDA, and EL, while cellular concentration of proline increased. Based on the finding, it was suggested that proline and H₂O₂ could play an important role in oxidative stress injury of grapevine leaves grown in vitro culture. Also, proline might have a direct positive effect on antioxidant enzyme system, membrane phase change, MDA, and EL.     

The effects of foliar applied CaCl2·2H2O,Ca(OH)2 and K2CO3 combined with the surfactants Glucopon and Plantacare on gas exchange of 1 year old apple (Malus domestica BORKH.) and broad bean (Vicia faba L.) leaves

Calcium chloride, calcium hydroxide, potassium carbonate and the alkylpolyglycoside surfactants Glucopon 215 CSUP and Plantacare 12 UP are salts applied to leaves as foliar nutrients and fungicides. These chemicals were sprayed on apple (Malus domestica BORKH.) and broad bean (Vicia faba L.) leaves. Stomatal conductance and rates of net photosynthesis were measured continuously in the light and in the dark using a Portable Photosynthesis System CIRAS-1. All compounds with the exception of Ca(OH)₂ affected stomatal conductance and net photosynthesis, albeit to different degrees. In light, Plantacare either alone (0.2 g l⁻¹) or in combination with CaCl₂·2H₂O (5 g l⁻¹) or K₂CO₃ (5 g l⁻¹) caused a rapid initial increase in stomatal conductance during the first 1–3 h after spraying on the leaves, maximum conductances were observed about 6 h after application. A rather high stomatal conductance was observed during the dark period when Glucopon (0.2 g l⁻¹) was applied either alone or in combination with Ca(OH)₂. The combination CaCl₂·2H₂O + Glucopon did not cause this elevated stomatal conductance during the dark. CaCl₂·2H₂O reduced stomatal conductance in combination with both Glucopon and Plantacare. The surfactant Plantacare reduced net photosynthesis during the first light period (12 h), if applied alone or in combination with CaCl₂·2H₂O. Treatment of broad bean leaves with K₂CO₃ + Plantacare resulted in a rapid decrease in net photosynthesis during the first hour, and then the rates of net photosynthesis increased rapidly and approached to those of the water control. The effects of surfactants and salts on net photosynthesis had nearly disappeared by the beginning of the second light period. Non-specific glycosidases presumably cleaved the glycosidic bond between the alkyl and the sugar moieties during the preceding night. Our data showed that foliar applications of CaCl₂·2H₂O and K₂CO₃ together with alkyl polyglycoside surfactants can affect gas exchange. However, the effects of the chemicals at the concentrations used in our study were not very large and were transient. They practically vanished within 24 h and a detrimental effect on growth and development of crops was not likely.     

Effect of GA3, Planofix (NAA) and Ethrel on granulation and fruit quality in ‘Kaula’ mandarin

The effect of GA₃ 15 mg l^?1, Planofix (NAA = 1-naphthalene acetic acid) 300 mg l^?1 and Ethrel 250 mg l^?1 on granulation and fruit quality in ‘Kaula’ mandarin (Citrus recticulata Blanco) was studied during 1975–1976. Three sprays of Planofix reduced the incidence of granulation to 30.7% from 62.7% in control. Three sprays of GA₃ were almost equally effective (31.3% granulation). These treatments also improved the fruit quality and gave the highest fruit weight, pulp percentage, juice, T.S.S., reducing and non-reducing sugars and ascorbic acid, and the lowest acidity, peel and rag. In both these treatments (3 sprays of GA₃ or Planofix) the T.S.S. was 9.3% (8.1% in control). The application of 3 sprays of Planofix 300 mg l^?1 or GA₃ 15 mg l^?1 is, therefore, considered to be successful in reducing the granulation in this cultivar of mandarin.     

Effect of ABA and sucrose on germination of encapsulated somatic embryos of guava (Psidium guajava L.)

Present study demonstrates the effect of sucrose and ABA on germination of encapsulated somatic embryos of guava (Psidium guajava L.). Sucrose and ABA at different concentrations were also evaluated for their effects on maturation and germination of somatic embryos. Mature somatic embryos developed on MS medium containing high concentration of sucrose (10%) or ABA (1.0 mg l⁻¹) showed inhibition in germination if they continued to be in same medium for 4 weeks. With increasing concentrations of sucrose (3–9%) or ABA (0.01–1.0 mg l⁻¹) in medium, percent germination of encapsulated somatic embryos decreased significantly. Encapsulated somatic embryos after storage on MS medium supplemented with 9% sucrose or 1 mg l⁻¹ ABA for different duration (0–60 days) germinated when they were transferred to medium containing 3% sucrose. About 20.8% and 37.5% encapsulated somatic embryos germinated after storage on ABA (1 mg l⁻¹) or sucrose (9%) for 60 days, respectively. Temporarily suppression in germination of encapsulated somatic embryos by high concentration of sucrose or ABA may be important for short-term conservation of elite genotype of guava.