不同基因型黄瓜性别与乙烯释放速率的关系

采用气相色谱法测定全雄株(ffMMaa)、雌雄同株(ffMMAA)、全雌株(FFMMaa、FFMMAA)和两性花株(FFmmAA)不同基因型近等基因系材料间的乙烯释放速率,探讨乙烯与黄瓜性型的关系。结果表明,不同近等基因系乙烯释放速率之间存在显著性差异。全雄株78♂(ffMMaa)的乙烯释放速率较低;雌雄同株406(ffMMAA)四叶一心期的乙烯释放速率大于两叶一心期;含6.33个F基因拷贝数的雌性系10098♀(FFMMaa)与F基因拷贝数为2.15的雌性系WI1983G(FFMMAA)相比,乙烯释放速率较低;雌性系WI1983G(FFMMAA)的乙烯释放速率极显著高于两性花株WI1983H(FFmmAA),两性花株WI1983H又极显著高于雌雄同株WI1983GM(ffMMAA);说明黄瓜性别表型与内源乙烯密切相关。从试验结果推断:雄株(ffMMaa)中乙烯释放速率低可能与A基因失活相关,雌性系(FFMMaa)乙烯释放速率可能受A/a基因的调控,两性花株(FFmmAA)中虽然M基因失活但内源乙烯释放速率并未降低很多,可能F基因产生的内源乙烯没有直接作用到两性花的雄蕊上。     

黄瓜雌雄株性别苗期化学鉴别方法

应用BTB(溴麝香草酚蓝 )法、NADH(还原辅酶Ⅰ )法和TTC(氯化三苯基四氮唑 )法对黄瓜雌雄株进行了苗期鉴别 ,结果表明 :雌、雄株提取液加入BTB液后雌株转色快于雄株 ,反应后 5h(小时 )内在 6 30nm处雌、雄株吸光值差异最大 ,是鉴别黄瓜雌、雄株的最佳时期。雌、雄株NADH含量和TTCH含量差异显著。BTB法、NADH法和TTC法鉴别雌雄株其差异显著概率均为极显著 ,BTB法和TTC法对雌、雄株混合群体的鉴别正确率均为 10 0 % ,二者可应用于黄瓜雌、雄株苗期鉴别。而NADH法对混合群体的鉴别正确率仅 71.4%。     

Genetics and molecular mapping of gynoecious (F) locus in cucumber (Cucumis sativus L.)

Gynoecious is an important economic trait of cucumber for determinant of earliness and yield, yet genetic mechanism is not well understood for this trait. The experiment was conducted using F₂ mapping population by crossing of PPC-2, a gynoecious and parthenocarpic line with Pusa Uday (monoecious and non-parthenocarpic cultivar). Out of 179 SSR markers screened, 39 markers differentiated the gynoecious and monoecious parents. However, only 17 markers were segregating with F₂ mapping population, those were used for genotyping and linkage map analysis and these markers were placed along with F locus on chromosome 6 covering a total distance of 100.4cM. The SSR markers, SSR13251 and UW020605 were found to be closely linked to gynoecious (F) locus at 1.0 and 4.5 cM, respectively. The segregation of F₂ population of PPC-2 × Pusa Uday and GPC-1 × Punjab Naveen and test crosses for sex type herein suggested that single dominant gene controlled the gynoecious sex expression in cucumber particularly in gynoecious genotypes PPC-2 and GPC-1. Therefore, the monogenic dominant nature of gynoecious sex identified in the present experiment and SSR markers closely linked to the F locus will be useful in marker-assisted backcross breeding for transfering gynoecious trait into horticulturally desirable varieties.     

Sex inheritance and development of gynoecious hybrids in bitter gourd (Momordica charantia L.)

Gynoecism has been used on a large scale in heterosis breeding of cucumber. Production of hybrid seeds in bitter gourd is highly expensive because it is done mainly through hand pollination. But utilization of a gynoecious line would be more economical and easier method. Since gynoecious parent has only female flowers, the open pollinated seeds it produces will be F₁ hybrid. It will reduce the cost of male flower pinching and hand pollination. Two gynoecious lines, DBGY-201 and DBGY-202 were crossed with two monoecious cultivars, “Pusa Do Mausami” and “Pusa Vishesh” and their F₂ populations were observed to determine the inheritance pattern of gynoecious sex form. Another experiment was conducted to determine magnitude of heterosis by utilizing nine inbred lines including one gynoecious line, DBGY-201 in diallel (without reciprocal) mating system. All the gynoecious hybrids showed significant heterosis in a desirable direction for traits like sex ratio (male:female), days to first picking, number of fruits per plant, yield per plant, and vine length. The segregation pattern in F₂ suggested that gynoecious sex form in bitter gourd was governed by single recessive gene. The gynoecious hybrids DBGY-201 × “Pusa Vishesh” and DBGY-201 × “Pusa Do Mausami” were important for early harvest (～50 days after sowing) whereas DBGY-201 × “Priya” and DBGY-201 × “Arka Harit” were promising for higher yield.     

山东银莲花种子萌发特性研究

以山东特有野生花卉山东银莲花为试材,对其种子萌发特性进行了研究。结果表明:山东银莲花种子萌发启动时间长,萌发过程中无发芽高峰;最适发芽温度为20℃;赤霉素处理能明显提高种子发芽率,最适赤霉素浓度为500 mg/L;低温层积20 d后再用200 mg/L赤霉素处理效果最好,发芽率达90.67%。     

In situ induction of chromosome doubling in vine cacti (Cactaceae)

Vine cacti have economic potential as exotic fruits in semi-arid and arid lands due to their high water use efficiency. The goal of this study was to attain autopolyploid plants by applying the antimitotic agents colchicine and oryzalin on axillary vegetative buds and germinating seeds. The diploid Hylocereus monacanthus and the tetraploid H. megalanthus; the interspecific triploid hybrid S-75, were studied. The effects of different concentrations and exposure times on bud survival and germination rate were recorded. A negative effect on vegetative bud survival was observed in the triploid hybrid. An inhibitory effect on germinating seeds was species specific, being greater on H. monacanthus with oryzalin and on H. megalanthus with colchicine. Putative polyploids were identified by comparing stomatal density between donor plants and plants arising from treated buds or seeds. Flow cytometric analysis and chromosome counts confirmed polyploidization in 14 autotetraploid H. monacanthus, 1 autohexaploid S-75 hybrid, and 14 autooctaploid H. megalanthus. This is the first report of artificial autopolyploidization in species of vine cactus, providing valuable novel plant material for further breeding programs.     

Somatic embryogenesis and plant regeneration in black pepper (Piper nigrum L.): I. Direct somatic embryogenesis from tissues of germinating seeds and ontogeny of somatic embryos

Summary

A protocol was developed for induction, maturation and germination of somatic embryos from the tissues of germinating seeds of black pepper (Piper nigrum L.). Explants were cultured on growth regulator – free solid SH medium maintained in the dark. The first somatic embryos developing directly from the explant tissue were noticed after 60 d of culture. Somatic embryos originated from a ring-like tissue on the micropylar region of the seeds. Sucrose concentration of the medium was found to be crucial for the induction of somatic embryos, and 30 g l^–1 was found to be the optimum. Maturation and germination of somatic embryos were achieved on the same medium. Suspension culture enhanced the process of maturation and germination. Regenerated plants were established in soil. Histology confirmed the ontogeny and each stage of development. Growth regulators were found to inhibit the induction of somatic embryogenesis. Cytological analysis of the regenerated plants revealed the normal chromosome number of 2n=52.     

水杨酸对NaCl胁迫下黄瓜种子活力及抗盐性的影响

以黄瓜种子为试材,采用SA进行浸种处理,研究SA对缓解黄瓜种子盐害的效应。结果表明:不同浓度SA浸种能在一定程度上提高黄瓜种子抗盐能力,其发芽率、发芽势和发芽指数均较对照组高,而种子MDA含量和外渗液电导率均低于对照组。其中0.50 mmol/L SA处理的种子的发芽率、发芽势和发芽指数最高;而0.75 mmol/L SA处理对种子MDA含量和外渗液电导率的降低效果最佳。适当浓度外源SA能够提高NaCl胁迫下黄瓜种子的活力,保护细胞膜的完整性,从而提高种子的抗盐性。     

NaCl胁迫对甜瓜种子萌发的影响

采用培养皿发芽法研究了不同浓度NaCl胁迫对甜瓜种子萌发的影响。结果表明:种子在吸胀阶段受盐胁迫影响较小,当种子萌动后高盐浓度对种子吸水有抑制作用。50mmol·L-1NaCl处理,对黄河蜜胚根生长有促进作用;50mmol·L-1以上,随着盐浓度增加,黄河蜜、白沙蜜、甘黄金种子的发芽速度逐渐降低,相对发芽指数、相对活力指数、胚根生长量均下降。盐胁迫对种子α-淀粉酶活力和膜修复的抑制可能是造成甜瓜种子萌发推迟和发芽势下降的主要原因。     

Low temperature and gibberellic acid stimulation of germination in Sambucus caerulea Raf

Sambucus caerulea (elder) seeds did not germinate after 4°C cool treatments for up to 30 days, when monitored for a further 30 days at 21°C. When seeds were soaked for 24 h in gibberellic acid (GA₃) prior to and during cold treatment, germination percentage depended on GA₃ concentration and duration of cold treatment. The highest germination percentage was 55 (1000 mg l⁻¹ GA₃ for 30 days at 4°C). When seeds were treated with ethephon at 0, 100 or 1000 mg l⁻¹, no germination was recorded after a subsequent 30-day 4°C treatment. Ethephon added to GA₃ gave a strong interaction, leading to further promotion in germination. Optimal germination was obtained after 1000 mg l⁻¹ GA₃ and 100 mg l⁻¹ ethephon for 30 days at 4°C (69%).The addition of ethanol, acetone, dimethyl sulfoxide or polyethylene glycol to the GA₃ soak as infusion agents either reduced or did not change the germination percentage.     

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.     

多叶羽扇豆种子成熟度和烫种对发芽的影响

为提高多叶羽扇豆种子的吸涨率和发芽率,对不同成熟度和烫种对种子发芽的影响进行了研究。结果表明:新收绿籽1 d吸涨率、发芽率和发芽势最高,分别达100%、96%和96%;烫种可以提高种子1 d吸涨率,烫种时间对种籽发芽的影响是烫种1 min,发芽率和发芽势最高,达72%和62%,随着烫种时间的增加,发芽率和发芽势逐渐下降。     

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.     

黄瓜性别决定相关基因在不同性型黄瓜种质基因组中的分布

根据已有的决定黄瓜雌性的ACC合酶基因CS-ACS1G,与黄瓜性型有关的ACC氧化酶基因CS-ACO2、CS-ACO3,与黄瓜雌性相关的乙烯受体基因CS-ETR2和CS-ERS的序列,通过设计特异引物,对不同性型黄瓜品种基因组DNA进行扩增。结果表明,5个基因在本试验所用的不同性型黄瓜品种的基因组中均能被检测到,说明这5个性别决定相关基因在本试验中不具有雌性特异性。通过PCR克隆在全雌性黄瓜品种G5224中获得了长度为1 124 bp的ACC合酶基因序列。BLAST分析表明,本试验所获得的ACC合酶基因序列和Trebitsh公布的CS-ACS1G基因序列的同源程度为99 %,表明PCR扩增产物确实为CS-ACS1G基因。此基因在基因组中表现不具雌性特异性的现象与多数研究者的结论相悖。     

赤霉素浸种对长期贮藏的茄子种子发芽的影响

为探索提高长期存放的茄子种子活力的方法,采用10种不同浓度赤霉素(200、400、600、800、1000、1200、1400、1600、1800、2000 mg/L)对长期存放的茄子种子分别进行4、6、8 h处理,比较其发芽效果。结果表明:使用适量浓度的赤霉素浸种能够有效地提高长期存放的茄子种子的发芽率、发芽势和发芽指数;其中400 mg/L赤霉素浸种8 h的效果最好,平均发芽率达97.33%,发芽势为93.00%,发芽指数为21.48;1800 mg/L赤霉素浸种8 h时,对种子发芽的促进效果消失;2000 mg/L赤霉素浸种8 h时,赤霉素抑制种子的发芽。     

Physical dormancy in myrtle seed

The nature of dormancy in seeds of myrtle (Myrtus communis L.) was investigated. Scarification with cold acid or sand paper and soaking in water increased seed germination, whilst stratification, inserting the seeds in boiling water or hot acid treatment decreased the number of germinating seeds. The highest germination was obtained by treating the seeds with 100 % cold acid for 60 min or 80 % cold acid for 120 min. Hard seed coat was found to be the principal cause of poor seed germination.Scarified and non-scarified seeds were germinated for 2 weeks at 6 temperatures between 5 and 30° C, and 20° C was optimum.     

A cold-treatment technique to improve the germination of vegetable seeds prior to fluid drilling

A simple method capable of treating large quantities of seeds prior to germination and fluid drilling is described. After an initial imbibition period at 20°C, seeds were placed at a temperature of 1°C; high enough for continued metabolism but too low for radical emergence. This treatment reduced the spread of time of germination, increased the percentage of seeds germinating and brought forward the mean germination time of seeds when transferred back to 20°C. Treated seeds emerged earlier and more uniformily than untreated seeds following pre-germination and fluid drilling in the field.     

反季节芫荽种子在不同条件下的萌发状态研究

为了寻找芜荽反季节栽培的最佳条件,将芜荽种子经过碾压处理、紫外线处理后繁鹩?00mg/L赤霉素、250mg/L芸苔素、100mg/L赤霉素 250mg/L芸苔素混合液浸种处理,观察种子的发芽状态并统计发芽数,计算发芽率等指标.结果表明:经过多种方法处理后能够有效地促进反季节芫荽种子的发芽,其中碾压处理后再以250 mg/L芸苔素浸种,不论发芽率、发芽势,还是活力指数都明显高于其它处理.该项研究为芜荽的反季节栽培提供了参考依据.     

A high-throughput seed germination assay for root parasitic plants

Background

Some root-parasitic plants belonging to the Orobanche, Phelipanche or Striga genus represent one of the most destructive and intractable weed problems to agricultural production in both developed and developing countries. Compared with most of the other weeds, parasitic weeds are difficult to control by conventional methods because of their life style. The main difficulties that currently limit the development of successful control methods are the ability of the parasite to produce a tremendous number of tiny seeds that may remain viable in the soil for more than 15 years. Seed germination requires induction by stimulants present in root exudates of host plants. Researches performed on these minute seeds are until now tedious and time-consuming because germination rate is usually evaluated in Petri-dish by counting germinated seeds under a binocular microscope.

Results

We developed an easy and fast method for germination rate determination based on a standardized 96-well plate test coupled with spectrophotometric reading of tetrazolium salt (MTT) reduction. We adapted the Mosmann’s protocol for cell cultures to germinating seeds and determined the conditions of seed stimulation and germination, MTT staining and formazan salt solubilization required to obtain a linear relationship between absorbance and germination rate. Dose–response analyses were presented as applications of interest for assessing half maximal effective or inhibitory concentrations of germination stimulants (strigolactones) or inhibitors (ABA), respectively, using four parameter logistic curves.

Conclusion

The developed MTT system is simple and accurate. It yields reproducible results for germination bioassays of parasitic plant seeds. This method is adapted to high-throughput screenings of allelochemicals (stimulants, inhibitors) or biological extracts on parasitic plant seed germination, and strengthens the investigations of distinctive features of parasitic plant germination.

     

A chilling-insensitive stage in germination of a low-temperature-adapted radish, rat’s tail radish (Raphanus sativus L.) cv. “Pakki-hood”

The rat’s tail radish (Raphanus sativus cv. “Pakki-hood”), cultivated in the northern part of Thailand, does not require low temperature for flower-bud initiation and shows high germinability even at low temperature. To analyze its characteristic temperature response, seedlings were subjected to a 3 day-chilling treatment at 0°C after a series of incubations for germination at 26°C which ranged from 3 h to 4 days. The chilling treatment after an initial stage (3 h to less than 2 days) of incubation at 26°C did not significantly affect the hypocotyl regrowth, but the same treatment after a more than 2-day incubation at 26°C reduced subsequent hypocotyl growth of plants. 1-aminocyclopropane-1-carboxylic acid (ACC)-dependent ethylene-forming activity was also reduced by the chilling treatment after 2–4-day incubation at 26°C. Electrolyte leakage from tissues of seedlings in the chilling treatment was increased in proportion to the length of the incubation at 26°C, indicating severe damage of chilling to plasma membranes after a longer incubation. We found a transition of chilling-sensitivity at 2 days in the incubation period for germinating seeds of Pakki-hood. Seedlings of Pakki-hood chilled earlier than the transition are relatively unaffected in their subsequent growth, but the seedlings become sensitive to chilling after the transition.