Effects of Pre-Stratification Storage Conditions on Black Walnut Seed Post-Stratification Germination Capacity

The objective of this work was to quantify changes in the germination capacity of Juglans nigra seeds following storage and then artificial stratification. Seeds were stored at 5 and –20 °C under 5% and 14% internal moisture content (IMC) for 0, 8, 10, and 12 months under conditions with oxygen or under vacuum. Germination percentage (GP) was affected by storage temperature, IMC, and storage period. Seeds stored with 5% IMC succeeded in germinating regardless of the temperature. Seeds stored with 14% IMC did not germinate (–20 °C) or germinated during storage (5 °C). The GP was reduced with the time of storage in seeds at –20 °C and 5% IMC and this effect was avoided in storage under vacuum. In conclusion, the germination capacity of black walnut seeds did not change for up to 12 months at low above-zero temperature and low IMC (5 °C, 5% IMC), being the most cost-effective alternative for long-term storage of black walnut seeds in commercial nurseries. Vacuum storage avoided the decrease of around 50% in average germination capacity of seeds stored for a year at –20 °C.     

Temperatures affecting embryo development and seed germination of Christmas rose (Helleborus niger) after sowing

Embryo development followed by seed germination was investigated in seeds of Christmas rose (Helleborus niger) held under different temperature conditions. The seeds had a heart-shaped embryo when dispersed from parent plants. That embryo developed rapidly to the torpedo stage at 25 °C, after which no further development occurred. When seeds with a torpedo-stage embryo were held at 15 °C, the embryos developed to the cotyledon stage, but no further germination occurred. Similar phenomena in the course of embryo development were observed in seeds held in a non-heated polyethylene house, in which the embryos developed to the torpedo stage at 20 °C or more, while further development to the cotyledon stage was attained only at temperatures of 15 °C or less. Seeds with a cotyledon-stage embryo rarely germinated until they were treated at 4 °C for more than 8 weeks. These results suggest that seeds of H. niger have a deep, simple morphophysiological dormancy caused by the combination of rudimentary embryos and a physiological dormancy that can be broken by cycles of warming and chilling.     

Storability of onion seeds and effects of packaging and storage conditions on viability and vigour

Fresh onion seeds desiccated to 6.0% seed moisture content (SMC) were stored in various packaging materials under different storage conditions. Seeds packed in aluminum-laminated pouches beside those stored with silica gel at 25 °C maintained satisfactory germinability and vigour after 12 months. Desiccated seeds stored in moisture impervious containers produced more vigourous seedlings. Germination potential of onion seeds increased with reduced SMC besides storage in moisture impervious packets along with desiccants as physiological and biochemical attributes are regulated. Seed viability and vigour decreased with accelerated ageing due to increased lipid peroxidation, decreased activities of several free radical and peroxide scavenging enzymes. Electrical conductance of seed leachates also increased with ageing. Thus, adoption of appropriate storage temperature and moisture control techniques would significantly affect onion seed quality, which was due to minimum accumulation of free peroxide radicals and enhanced activity of free radical scavenging enzymes.     

Influence of harvest time and after-ripening on the seed quality of eggplant

Eggplant cv. Emi and Tsakoniki were cultivated for seed in an unheated greenhouse and fruits were harvested at 25–65 days after anthesis (DAA) in order to determine the optimum harvest time. In addition, the effect of after-ripening on seed quality (i.e. seed size and germination) was examined by storing harvested fruit at 25 °C for 20 days prior to seed extraction. From the results, it was concluded that the optimum time of harvest for seed production is 55 DAA. Seeds extracted from fruits that were harvested at 25–35 DAA did not germinate, but when fruits harvested at the same age were stored for 20 days at 25 °C prior to seed extraction (i.e. seeds were after-ripened) germination was induced. Seeds extracted from fruits harvested at 45 DAA showed a high percent germination, which decreased after storage at 25 °C for 3 months. This decrease, however, was reduced by after-ripening prior to extraction. It is concluded that although eggplant is a non-climacteric species and fruit do not ripen after harvest, nevertheless seeds within the fruit continue to fill and mature after harvest; hence storage of prematurely harvested fruit prior to seed extraction permits the seeds of these fruits to after-ripen in situ and thereby increases seed size and germination. The implication of this result for eggplant seed production is discussed.     

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.     

Partial vacuum extends the longevity of primed bitter gourd seeds by enhancing their anti-oxidative activities during storage

This study evaluates the effects of partial vacuum storage on longevity and anti-oxidative responses of primed bitter gourd (Momordica charantia L.) seeds. Priming was achieved by mixing the seeds with moist vermiculite 25 °C for 36 h, followed by air-drying to the original moisture level. Primed seeds were vacuum-packed and stored at 25 °C for up to 12 months. Priming improved seed germination, reduced lipid peroxidation and enhanced anti-oxidative activity prior to storage. However, primed seeds accumulated more total peroxide than non-primed control after 12 months non-vacuum storage, and this led to a marked decrease in seed longevity. Increased total peroxide levels were associated with decreased percentage of 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radical inhibition. Partial vacuum storage proved useful in extending the longevity of primed seeds for up to 12 months. Improved longevity was related to enhanced anti-oxidative activity that minimized the accumulation of total peroxide during long-term storage.     

The influence of seed maturation on desiccation tolerance in Phalaenopsis amabilis hybrids

The Orchidaceae contains a large number of threatened species that could benefit from seed banking. However, successful seed storage requires a greater understanding of the enigmatic seed biology of orchids. In particular, there is little documentation of the presence or timing of the maturation drying that has been shown to be critical for longevity of agricultural seeds in storage. The aims of this work were to document seed water content, germinability and desiccation tolerance as a function of maturation in developing capsules of hand-pollinated flowers of Phalaenopsis hybrids. Lengthening of capsules was complete by 50 DAP, but capsule diameter continued to increase up to a maximum at 70 DAP. Relative water content rapidly declined from 75% moisture content (fresh weight basis) at 150 DAP to 50% moisture content at 165 DAP where it remained until dehiscence. Seed germinability remained high (75–99.5%) throughout the harvesting period (90–216 DAP), but desiccation tolerance only developed 165 days after pollination. Therefore, if Phalaenopsis seeds are to be stored, we propose that their harvest should be delayed until moisture content drops below 50%.     

In vitro germination and seedling development of cryopreserved Dendrobium hybrid mature seeds

In vitro germination and seedling development from Dendrobium Swartz. hybrid ‘Sena Red’, ‘Mini WRL’, ‘Jaquelyn Thomas’, and ‘BFC Pink’ seeds cryopreserved through vitrification (PVS2) were evaluated. Germination percentages after cryopreservation (LN) were variable among different controls and treatments, despite the initial high seed viability for all hybrids. Seeds exposed to PVS2 at ice temperature from 1 to 3 h prior to LN exhibited significantly higher germination than seeds exposed to PVS2 at room temperature for the same time periods. No significant differences in germination percentages were observed for time exposure to PVS2 at 1, 2 or 3 h for ‘Sena Red’, ‘Mini WRL’, and ‘BFC Pink’. Seeds of ‘Jaquelyn Thomas’ exposed to 1 h prior to LN showed higher germination percentage than for exposure to 2 or 3 h. The combination of a pre-cooling treatment (ice) with a dehydration treatment (PVS2) for a period of time of 1–3 h was essential to allow proper germination of cryopreserved seeds. Although variability in seed germination among different hybrids and treatments was observed, germination was above 50% of the controls and all germinated seeds developed into normal seedlings with healthy shoot and root formation. No abnormalities, nutritional deficiencies, or diseases were observed in developed seedlings and no significant differences were observed for seedling growth and development from germinated seeds among the different hybrids. Seedlings transplanted to pots acclimatized well and developed into normal plants within 6–8 months in greenhouse. Transplanted seedlings exhibited 100% survival for all hybrids.     

超干燥处理对豌豆种子抗氧化系统酶及热稳定蛋白的影响

 将含水量为12.2% , 11.3% , 8% , 5% , 4% , 3%的碗豆种子置于50℃干燥箱中人工老化,定期测定老化种子生活力和活力指标, 抗氧化系统酶活性及热稳定蛋白。结果表明: 与对照相比, 含水量4%和3%超干燥种子的活力指数、根干样质量显著下降, 而含水量8% , 5%的种子活力指数、发芽率和根干样质量没有出现明显下降。POD活性和CAT活性与种子的发芽率、活力呈正相关, 当老化处理6个月后, 含水量3%和4%的POD活性和CAT活性低于对照, 但含水量5%和8%的高于对照。超干燥种子中没有发现新的热稳定蛋白谱带, 但含水量为8%和5%的种子其热稳定蛋白质的含量增加。     

甘菊与栽培菊‘金陵黄玉’种间杂交失败的原因

 二倍体野菊与栽培菊种间杂交常不能结实, 从而严重影响了野菊优异基因的利用, 为了揭示其原因, 以栽培菊(Dendranthema grandiflorum) ‘金陵黄玉’为母本, 二倍体野生菊甘菊(D. lavandulifolium ) 为父本, 开展了种间杂交, 测定了父本花粉活力, 研究了授粉后花粉在柱头萌发行为及胚胎发育情况等。结果发现, 父本甘菊的花粉活力在授粉时为11.2% , 人工授粉4 h内未观察到柱头上有花粉萌发;授粉后8 h时平均每个柱头上只有7.5粒花粉萌发; 到授粉后12 h时数量达到最多, 为16.1粒; 随后数量急剧下降, 到24和48 h时柱头萌发花粉数量分别只有3.2粒和2.4粒, 且大部分花粉管生长异常并停留在柱头表面。此外, 在授粉8 d后观察到12.0%子房中含有正常的球形胚, 但之后就未观察到正常胚胎, 最终未获得杂交种子, 而母本自然开放结实率高达42.3%。以上结果表明, 受精前、后的生殖障碍, 即母本柱头上花粉萌发数量少且萌发异常和受精后胚胎大量败育, 是引起种间杂交不结实的主要原因。     

Promotion by 5-aminolevulenic acid of pepper seed germination and seedling emergence under low-temperature stress

The effects of incorporating 5-aminolevulenic acid (ALA) into the priming solution on low-temperature germination and emergence percentage performance of red pepper (Capsicum annuum cv. Sena) seeds before and after seed storage were investigated. Seeds were primed in 3% KNO₃ solution for 6 days at 25 °C in darkness containing 0 ppm, 1 ppm, 10 ppm, 25 ppm, 50 ppm or 100 ppm ALA. Following priming, seeds were either immediately subjected to germination and emergence tests at 15 °C or stored at 4 °C or 25 °C for 1 month after which they were subjected to germination and emergence tests at 15 °C. Priming pepper seeds in the presence of ALA improved final germination percentage (FGP) and germination rate (MGT) at 15 °C compared to non-primed seeds. The highest FGP was obtained from seeds primed in the presence of 25 ppm and higher ALA concentrations while the highest MGT was obtained from seeds primed in KNO₃ supplemented with 10 ppm ALA. Emergence percentages were the highest for the seeds primed in the presence of 25 ppm ALA and 50 ppm ALA while non-primed seeds had the lowest emergence percentage. Highest emergence rates (MET) and heaviest seedlings were also obtained from seeds primed in KNO₃ supplemented with 50 ppm ALA. Although all priming treatments improved germination and emergence performance of pepper seeds at 15 °C following 1 month of storage under two different temperatures, inclusion of 25 ppm and 50 ppm ALA into the priming solution resulted in higher germination and emergence percentages and faster germination and emergence compared to seeds primed in KNO₃ only and non-primed seeds. These results indicate that priming seeds in 25 ppm and 50 ppm ALA incorporated into the KNO₃ solution can be used as an effective method to improve low-temperature performance of red pepper seeds and that these seeds can be stored for 1 month at 4 °C or 25 °C and still exhibit improved germination and emergence performance at 15 °C.     

Seed germination of seven pepper cultivars at constant or alternating high temperatures

Summary

Seeds of seven pepper (Capsicum annuum L.) cultivars (Anaheim TMR 23, California Wonder 300, Coronado, Jalapeno M, Ma Belle, Mercury, and Yolo Wonder B) were germinated at constant day and night temperatures of 25,30,35 and 40°C or at alternating temperatures of 40/25,40/30 and 40/35°C for 14 days. Germination percentages and rates were similar at 25 and 30°C. Largest differences in cultivar responses occurred at 35°C where germination percentages ranged from 24 to 96%, and rates, calculated as summation of the number of seeds germinated on a given day divided by day number, varied from 3 to 26 (theoretical maximum value of 100). At 40°C, germination percentages were less than 5% and rates were less than one for all cultivars. Cultivars with the most heat tolerance were ‘Mercury’ and ‘Yolo Wonder B’. At alternating temperatures, germination percentages and rates were higher than those at constant 40°C. The increases were greatest when the temperature was lowered by 15°C (40/25°C) and least when temperatures were lowered by 5°C (40/35°C). Tetrazolium tests showed that a large percentage of the ungerminated seed was still viable from the highest temperature. At lower temperatures, fewer ungerminated seeds were viable with no viable ungerminated seeds from the lowest temperature.     

大白菜超低含水量种子保存研究

５种含水量（５％～１％）的大白菜８７－３种子，分别在４种温度下（－２０℃、４℃、常温、４０℃）贮藏３年，其生活力在常温贮藏与在－２０℃、４℃下贮藏没有显著差异，４０℃贮藏种子生活力明显下降，４℃及常温下超干贮藏３年对大白菜种子生活力没有影响。８７－３在常温贮藏的最佳含水量约为３％～２％。     

Effects of after-ripening,stratification and GA3 on dormancy release and on germination of wild asparagus (Asparagus acutifolius L.) seeds

Seeds of wild asparagus (Asparagus acutifolius L.) were treated and compared in this research to investigate seed dormancy class and level involved in this species. Four seed lots were compared: (i) freshly harvested seeds in 2007 (07Fr); (ii) freshly harvested seeds in 2008 (08Fr); (iii) after-ripened (AR) 2007 seeds dry stored in glass jars (ARg); (iv) AR 2007 seeds dry stored in paper bags (ARp). The 07Fr seeds were exposed to (1) chemical scarification combined with gibberellic acid (GA₃) levels (0, 200, 400, and 600 mg L⁻¹) and to (2) 28-day moist stratification at 5 and 23 °C, and two sequences of 5/23 °C combined with 0 and 400 GA₃ mg L⁻¹ levels, and (3) together to the 08Fr and AR seeds were exposed to 56-day moist stratification at 5, 23, or 5/23 °C. With the 08Fr and AR seed lots this last stratification treatment was combined with 0 or 800 GA₃ mg L⁻¹ levels. The dormancy depth of 08Fr (32% germination) was less than 07Fr seeds (2%). The latter after-ripened during dry storage and when stored in glass germinated more (47.5%) than in paper (12%). Stratification for 4 weeks was ineffective in improving germination of 07Fr seeds; when chemically scarified they did not germinate at all. The highest (nearly 70%) and the most rapid and uniform germination were observed for all the lots when they were warm stratified for 56 days. Warm stratification improved germination more than alternate temperature stratification, while cold stratification inhibited germination especially for the 08Fr and ARg lots, thus seeds seem not to have a morphological component to their dormancy. GA₃ only improved germination of 07Fr seeds, at a low rate. A. acutifolius seeds fit the characteristics of a non-deep physiological dormancy.     

The germination of watercress (Rorippa nasturtium- aquaticum) seeds. I. The effects of age,storage, temperature,light and hormones on germination

The upper temperature limit for germination of watercress seeds was higher in the light than in the dark. Seeds became progressively less dormant following harvest, the upper temperature limit for germination in both light and dark becoming higher and the rate of germination increasing. Earlier-ripening seeds were more dormant than later-ripening ones. High humidity or a short period at high temperature during storage hastened dormancy loss. Germination at 20 °C in the dark could be induced by treatment with a combination of GA₄, GA₇ and benzyladenine. The promotion of germination by red light was nullified by immediate exposure to far-red light, indicating that the effect of light was mediated through phytochrome. The practical relevance of the results is discussed.     

Mini-Nut Propagation Technique of Kola (Cola nitida, (Vent.) Schott and Endl.): Prospects for Germination and Propagation of Kola Plantlets in the Pre-Nursery

Limitations against propagation of Cola nitida include pronounced dormancy of between 1 and 8 months after sowing (MAS) leading to uneven germination and seedling growth. This experiment was conducted in a screenhouse, Federal University of Agriculture Abeokuta, Nigeria, to evaluate the effects of mini-nut and nut-color on germination and seedling growth of C. nitida nuts. The experiment was in a completely randomized design replicated 3 times. Treatments comprised two factors: nut/seed-colored biotype (white, pink, and red) and mini-nut (embryonic portion of cotyledon) [excised embryonic portion cotyledon (EEPC), 25% embryonic portion cotyledon (EPC), 50% EPC, 75% EPC, and 100% EPC (whole nut/seed)], giving 15 treatment combinations sown in plastic cups of 50 cl filled with sawdust. Germination percentage and morphological growth of plantlets (plant height (cm), number of leaves, dry matter yield (g/plant)) were monitored; data subjected to analysis of variance and mean comparisons done (p ≤ 0.05). As early as 4 WAS, the EEPC and 25% EPC had 67.78% and 54.44% germination, respectively. Within the same period, 51.33%, 48.00%, and 31.33%, respectively, of white-, pink-, and red-colored seeds germinated. At 6 WAS, the white-, pink-, and red-colored seeds had mean germination of 80.67%, 92.00%, and 72.67%, respectively. At 12 WAS, germination was observed to complete with the pink-, red-, and white-colored nuts having 97.33%, 92.61%, and 91.33%, respectively. Within the same period, the mini-nut sizes had between 92.22% and 95.56% germination. Combining the two factors, 50% EPC, 25% EPC, and EEPC of white-nut biotype germinated earliest with 50.00–76.67% at 4 WAS and 73.33–80.00% at 5 WAS. The EEPC of pink-colored biotype attained 100% at 6 WAS, while other treatments were between 56.67% and 93.33%. Thus, while earliness in germination pattern follows the order: EEPC > 25% EPC > 50% EPC > 75% EPC > whole nut, the plantlet morphological growth followed a reverse order. With mini-nut technique therefore, timely and even germination of kola nuts were obtained and 50%EPC would be recommended for conventional propagation while EEPC would require nutrient amendment for improved growth.     

The Effect of Scion on Root.: II. Stem-Worked Apples.

Summary

The effects of seed coat removal and chilling on the germination of seeds of ten cultivars of ornamental peach (Prunus persica Batsch) were investigated. Seeds were rinsed in running tap water for 48 h in order to facilitate seed coat removal. Only a few non-chilled, intact seeds germinated (e.g., 6% of ‘Hito’ seeds). Seed coat removal and no chilling resulted in some seed germination in eight of the ten cultivars, ranging from 6% to 83%. Chilling intact seeds at 5°C for up to 10 weeks resulted in greater frequencies of germination (average = 85% germination) than seed coat removal before (average = 80%) or after chilling (average = 73%). There was a linear decrease in the germination percentage with an increase in abscisic acid (ABA) content for ‘Yaguchi’,‘Kanpaku’, and ‘Kikumomo’ seeds (R = –0.66; P <0.001). The most consistent decrease in total seed ABA content (average of 64%) occurred during the 48 h rinsing period. In ‘Kanpaku’, dry seeds had an intermediate ABA content (13 ng per seed); but, in the embryonic axes, this increased from 0.03 ng to 1.2 ng per seed with an increase in the duration of the chilling period. The lowest germination percentages were found in this cultivar. These results suggest that ABA synthesis in the embryonic axes during chilling may affect the varietal characteristic of seed dormancy, and that rinsing seeds for >48 h could remove sufficient ABA to allow seed germination with minimum chilling.     

In vitro development and germination of immature olive embryos

Summary

In vitro culture methods were used to germinate olive embryos prior to maturation. Fruit, seed and embryo development were established with consecutive sampling from 20 to 100 days after bloom. For that same period, embryo development and germination success were determined by in vitro culture trials using one-third strength MS medium with or without the addition of zeatin. For early developmental stages, when isolation of the embryo was difficult, a cut portion of the seed containing the embryo was used for culture. The embryos cultured within the cut seed portions germinated and formed normal plantlets. Histological observations indicated a close similarity between the natural and in vitro immature embryo differentiation pattern, progressing through preglobular, globular, heart-shaped and torpedo-shaped stages. In some cases, however, the in vitro immature embryos developed or germinated abnormally. The presence of zeatin (0.25 mg l^–1) in the culture medium and the use of a cut seed-portion containing the immature embryo allowed in vitro germination sooner after bloom than previously obtained. On the contrary, zeatin was a handicap for mature olive embryo in vitro germination, which reached 100% seedling formation when no plant growth regulators were used.     

Mass propagation of Satyrium nepalense D.Don.—A medicinal orchid via seed culture

An in vitro plant regeneration protocol was successfully established in Satyrium nepalense, a terrestrial orchid by culturing immature seeds from unripe fruits. Seeds were germinated on Murashige and Skoog, Knudson C and Knudson C modified Morel medium. The germination of the seeds and development of protocorm was highest in MS medium (86.7%) followed by Knudson C modified Morel medium (74%) and Knudson C medium (61.2%). Among the cytokinins tried for multiple shoot induction from the protocorm, 1-phenyl-3-(1,2,3-thiadiazol-5-yl)-urea (TDZ) was found to be superior. Indole-3-butyric acid (IBA) was effective for inducing healthy roots. Well-developed plantlets were hardened in vermicompost (leaf litter + cow dung 1:1), sand and coconut husk (1:1:1).     

提高草莓种子离体培养发芽率的研究

该文以EMC、‘哈尼’‘丰香’‘北辉’等10份草莓为试材,研究了培养基质和种子处理对发芽的影响．以提高草莓种子的发芽率。结果表明：草莓种子处理、培养基质、品种等对发芽率、发芽速度有很大影响。种子整粒培养,栽培品种发芽困难,而野生品种发芽较容易,种子切开处理的,在不同的培养基质上,供试各品种的种子发芽率超过60％．最高达100％。培养基质以1,2MS＋3％蔗糖＋0．6％琼脂的为好,发芽率达90％以上。