秋水仙素诱导文旦柚2n配子获得自交三倍体

 以‘土佐文旦’柚成树为材料, 探讨了秋水仙素诱导2n配子的方法, 研究了秋水仙素浓度和处理时期对获得三倍体的影响。结果表明: 开花前1周用0.25%的秋水仙素处理花蕾, 可诱导2n配子自交亲和。经对发芽存活的自交后代植株的叶片细胞核DNA量检测和细胞学鉴定, 确定25%的自交后代植株为自交三倍体。通过秋水仙素诱导文旦2n配子是获得自交三倍体的有效途径。     

Induction of viable 2n pollen in sterile Oriental × Trumpet Lilium hybrids

In order to induce viable 2n pollen from highly sterile diploid Oriental × Trumpet (OT) (Lilium), N₂O was used to treat flower buds of four sterile diploid OT cultivars (‘Nymph’, ‘Gluhwein’, ‘Yelloween’, and ‘Shocking’) at different stages of meiosis. There was no pollen germination in the controls. However, after N₂O treatment at 600 kPa, three of the OT hybrids (‘Nymph’, ‘Gluhwein’, and ‘Yelloween’) not only exhibited fertile flower percentages (4.3–16%), but also higher rates of pollen germination (18.8–72.5%). In addition, both the fertile flower percentages and rates of pollen germination were higher following 48 h N₂O treatment at 600 kPa than the 24 h treatment. Following 72 h N₂O treatment at 600 kPa, most flower buds or plants were damaged and any undamaged flowers showed abnormal anthers at the time of flowering. This indicated that 48 h of N₂O treatment at 600 kPa was optimal to induce viable 2n pollen in three out of four sterile hybrid OT lily cultivars. These results also showed that prophase I – metaphase I was the optimum stage of meiosis at which to induce 2n pollen by N₂O treatment in lily hybrids.     

Chromosome Number Manipulation as Part of Potato Pre-breeding Programs

The cultivated potato(Solanum tuberosum L.) is a tetraploid(2n=4x=48) and can be improved with the incorporation of desirable traits from other Solanum species.Often the transfer of these traits is hindered by complex genetics and breeding barriers within potato.Parthenogenesis and microsporogenesis are used in chromosome number manipulation allowing breeders to reduce the potato's chromosome number to dihaploid(2n=2x=24)[diploid] or monohaploid(2n=x=12) from which a predictable transfer of traits can be made,in accordance with the endosperm balance number theory(EBN).Furthermore,the reproductive processes of first division restitution(FDR) and second division restitution(SDR) are utilized in order to increase the chromosome number for incorporation into the cultivated potato.     

大白菜2n配子发生的遗传分析

遗传分析表明,大白菜２ｎ配子发生受隐性单基因控制,遵循孟德尔遗传规律。在参与受精的２ｎ配子中,２ｎ雌配子较２ｎ雄配子具有较高的受精传递率。     

水稻籼粳亚种间杂种广亲和基因与不育基因

克服杂种不育性是利用籼粳亚种间杂种优势的关键。总结了目前已定位的籼粳亚种间杂种的广亲和基因、雌配子败育座位、雄配子体败育座位及花粉不育座位等,并提出了把"广亲和基因"和"特异亲和基因"结合利用的设想。     

无籽八月橘花粉育性观察

运用酸解及改良卡宝品红染色压片相结合的方法,对无籽八月橘及其有籽原种的花粉母细胞减数分裂过程、花粉粒形态、生活力、发芽率和畸形率等指标进行了观察.结果表明,无籽八月橘花粉母细胞减数分裂正常,能形成正常的四分孢子,且花粉的育性较强,与其有籽原种的育性无显著差异,表明无籽八月橘无籽与花粉育性无关.     

葡萄牙牡蛎与熊本牡蛎种间配子亲和力及合子育性分析

为了评估葡萄牙牡蛎(AA)与熊本牡蛎(SS)的种间配子亲和性及合子育性,以成熟的这两种牡蛎为材料,研究了温度(18、21、24、27和30℃)、盐度(16、20、24、28和32)对其受精率、孵化率的影响;在最优环境条件组合下,估算了不同精子浓度下(100、101、102、103和104个/μL)受精率及孵化率的F50临界值。结果表明,SS、AA及SA受精率和孵化率随着温度升高先上升后下降,在27℃时出现最大值,分别为99.1%±0.3%、98.4%±1.2%和81.3%±2.8%;孵化率变化趋势与受精率相似,也在27℃时出现最大值,分别为99.1%±0.5%、96.8%±2.8%和67.1%±5.5%。SS和SA在盐度24时出现最高受精率,分别为98.8%±1.3%和81.1%±7.4%,AA为94.8%±4.5%;SS和SA在盐度24时出现最大孵化率,分别为75.9%±3.7%和66.1%±4.5%,此时AA孵化率为86.4%±4.2%。在温度27℃、盐度24环境条件下,SA和AA在精子浓度103个/μL时受精率最高,分别为92.4%±1.2%和87.2%±5.7%,SS受精率为92.5%±2.2%;此时的孵化率分别为82.2%±7.0%、78.9%±7.8%和79.8%±4.3%,各实验组间无显著差异。采用一元二次方程估算,SA受精率F50值的精子浓度为58.88个/μL,孵化率F50值的精子浓度为208.93个/μL。本研究为葡萄牙牡蛎与熊本牡蛎生殖隔离机制及其种间杂交奠定了理论与实践基础。     

Fertilizing ability of gametes at different post‐activation times and the sperm–oocyte ratio in the artificial reproduction of pikeperch Sander lucioperca

The time period during which oocyte and spermatozoa retain their fertilizing ability after contacting with water was evaluated in pikeperch (Sander lucioperca). In addition, success of in vitro fertilization was examined regarding to the sperm‐to‐oocyte ratio (SOR). In the first trial, oocytes were placed in Petri dishes containing 5 ml of the hatchery water, to which freshly collected and pooled sperm were added to each sample at 0, 15, 30, 60, 90, 120, 150 and 180 s post oocyte activation. The oocytes retained their fertility for at least 30 s after contacting with water. The second trial tested the maximum time period during which spermatozoa retained fertilizability after contacting with water. Milt (50 μl) was collected from each male and added to 5 ml of water in Petri dishes. Thereafter, oocytes were added at 0, 5, 15, 30, 60 and 75 s post‐sperm activation. Delays exceeding 10 s affected negatively the fertilization success. The third trial examined the optimum SOR; in which was found that 100 × 10³ spermatozoa per oocyte were the minimum ratio to ensure fertilization rates above 70%. Overall, the data clarified some biological interactions of gametes in the artificial propagation of pikeperch.     

大白菜部分单体雄配子发育的观察研究

对大白菜3号、5号、10号等3个单体的雄配子体发生发育进行了细胞学观察,结果表明3个单体的花粉败育是从小孢子时期开始的,导致败育的原因主要是绒毡层的肥大和延迟解体,另外,在雄配子体的发育过程中出现的四分体大小不均、花药畸形、花药药隔维管束数目增多和药室合并等异常现象对单体花粉败育的也有一定的影响。     

Characterization of the quality of the gametes and sex steroid levels during spring and summer spawning events in pejerrey Odontesthes bonariensis reared under natural conditions of temperature and photoperiod

Pejerrey Odontesthes bonariensis spawning period takes place during the end of winter and spring and, depending on temperature conditions, during late summer and autumn. Nevertheless, the occurrence and quality of the summer–autumn spawning period have not been well documented and are not considered for aquaculture production. In this context, this study aimed to characterize the reproductive activity of pejerrey reared in captivity under natural conditions of temperature and photoperiod throughout a year in order to summarize the spawning quality of the two spawning periods. The present results showed that pejerrey might spawn from late winter to the end of the spring with a peak in October (mid‐spring) and, also during summer and early autumn, interrupted by a period of 56 days without spawning activity in between. The extension of both spawning periods was almost equal (67 and 69 days). Nevertheless, higher relative fecundity and larger egg size were observed during the first spawning period, associated with higher levels of oestradiol measured in females demonstrating that it is better than the second spawning. The fertilization rate was not affected throughout the reproductive periods. These differences in the reproductive parameters are discussed in order to design specific strategies to increase seed production.