The effect of seed extraction methods on seed quality of two cultivar's tomato (Solanum lycopersicum L.)

In order to compare of different methods and identify the optimum condition for tomato seed extraction, factorial experiments with 3 replications was conducted. In the first experiment, pulp of two tomato cultivars (Faraon, Dominator) were fermented at two temperatures (25, 35 degrees C) and six periods (24, 48, 72, 96, 120, 144 h). The germination of seeds in laboratory as well as seedling emergence and preliminary growth in greenhouse were studied and measured. The results showed that effect of cultivar on traits (except of seedling emergence) was significant. Also the effect of temperature of fermentation, duration of fermentation and also interaction effects of them on seed germination were significant. Totally seed quality decreased with increasing temperature and duration of fermentation and the fermentation duration from 24 to 48 h at temperature 25 degrees C, is recommended. In the second experiment, tomato seeds were extracted by HCL (pH was arranged to 1, 2, 3 for 10, 20, 30 min), H2SO4 (pH was arranged to 1, 2, for 15, 30 min), Sodium carbonate (5, 10% for 24 and 48 h) and fermentation. Percentage germination, germination rate, length of radicle and length of plumule were used for seed quality assessment. The results showed that interaction effect between pH and duration of HCL treatments was significant for seed germination (percentage and rate) and there was an interaction effect between concentration and duration for germination rate in alkali treatments. Different extraction methods had not detrimental effect on percentage germination, but acid treatments produce very bright clean seeds in compare to other treatments.     

Study of some factors of conservation of pollens of two plant species (Callistemon rigidus and Hymenocardia acida) of bee flora of Adamawa (Cameroon)

To contribute to the preservation of the bee flora of Adamawa, a study to determine the optimal conditions for preservation of Callistemon rigidus and Hymenocardia acida pollens, two endangered bee species, was conducted from March 2006 to March 2007 in this region. The study began by anthers collection at the experimental site and they were brought to the laboratory where fresh pollens are collected and undergo in vitro germination and storage tests. These tests have required the installation of two solidified media culture: Brewbaker and Kwack (BK) and Heslop-Harrison (HH) media to evaluate pollens germination under the influence of some physiological factors and assess the influence of storage at + 10 and -20 degrees C with and without initial drying. The results show that sucrose concentrations of 10 and 15% on BK medium has produced respectively 60.69 +/- 3.1 and 04.49 +/- 0.21% as the highest values of germination percentage in Callistemon rigidus and Hymenocardia acida. Temperatures of 30 and 25 degrees C which produced 60.69 +/- 2.53 and 04.25 +/- 0.29% of germination and pH 5 with 55.14 +/- 4.14% and 6.8 with 04.54 +/- 0.6% were respectively favourable in the same order for the germination of both species of pollens. Time for a week of drying allowed the extension of storage time of both species of pollens as from +10 to -20 degrees C. The Callistemon rigidus pollens were generally more tolerant to the storage at-20 degrees C showing the critical period of storage exceeding 22 weeks while those of Hymenocardia acida were less tolerant to both temperatures with most critical period of storage established to 8 weeks.     

Germination of Astragalus hamosus L. and Coronilla scorpioides (L.) as influenced by temperature

Seed germination of two pasture legumes was tested under dark conditions at three alternating temperatures of 5-20, 15-20, 20-35 degrees C and constant 20 degrees C. Duration of the alternating temperatures was 12 h. The seedling counts were checked every day during four weeks. Species differed significantly in germination response to temperature. A. hamosus was more sensitive to temperature than C. scorpioides. The temperature of 20-35 degrees C was more favourable for the germination of A. hamosus than constant 20 degrees C which markedly reduced its germination. The interaction between accessions and temperatures for total germination was significant in both species. In A. hamosus, almost 50% of germination was achieved by all accessions by the first week at alternating 20-35 degrees C temperature while in C. scorpioides, average total germination was significantly low (4%) even by the 28th day. A total rate of 11 and 9% of germination were recorded by two accessions from Ouesslatia (210) and Agareb (19), respectively. A considerable variation for germination was observed among accessions of both species. Temperature requirements for seed germination of the studied species suggest why they are relatively easy or difficult to establish in the field. A. hamosus, with very small seeds required relatively high alternating temperature for germination than C. scorpioides which was insensitive to temperature and has relatively bigger seeds.     

Germination responses of the halophyte Chloris virgata to temperature and reduced water potential caused by salinity,alkalinity and drought stress

Chloris virgata is considered a useful grass species for grassland restoration in northern China. However, little information exists concerning the germination responses of this species to temperature and water potential caused by stress conditions. Experiments were conducted in growth chambers to assess the effect of temperature, salinity, alkalinity, drought and the interactions of temperature and stress on seed germination. Seeds were germinated at three diurnal temperature regimes, with four water potentials in NaCl, NaHCO₃ and PEG solutions. Results showed that optimal germination under stress occurred at 15–25 °C, and germination percentages and rates were inhibited by either an increase or decrease in temperature from the optimal temperature. The inhibitory effects of the low water potential caused by salinity and drought on germination were greater at 25–35 °C, but seeds were subjected to more stress despite the relatively higher water potential because of the alkalinity at this temperature. The recovery percentage under salinity was highest at ?1·2 MPa at 15–25 °C, and more than 80% of seeds also germinated at this water potential after they were transferred from drought stress. However, seeds lost their viability in higher alkalinities under all temperatures, and at 25–35 °C, there was lower recovery percentage under stress. Results suggest that salinity, alkalinity and drought stress have different impacts on seed germination, and the tolerance to stress of C. virgata seeds is affected by the interactions of temperature and water potential caused by salinity, alkalinity and drought. Chloris virgata shows potential utility as a promising grass species in salinity–alkalinity and drought‐stressed environments.     

几种化学药剂对杂交籼稻汕优63自然老化种子引发效果研究

用聚乙二醇（PEG）、聚乙烯醇（PVA）、KNO3、PEG＋KNO3、PVA＋KNO3等几种化学药剂对自然老化的杂交籼稻汕优63种子进行引发效果研究,以筛选最佳处理方法。结果表明,从引发效果和经济实用两方面考虑,以0.5%PVA＋1.0%KNO3处理1 d为最佳。经过该处理的汕优63自然老化种子的发芽率显著提高,比对照（63.0%）提高了11.7个百分点,活力指数、发芽势、苗高、苗重也均较对照显著提高,且成本较低。     

Storage factors control germination and seedling establishment of freshly harvested true potato seed

Freshly harvested true potato(Solanum tuberosum subsp.andigena, Juz. et Buk.) seeds of the ancient Peruvian cultivar Ccompis were dried to 3.4, 4.2,5.1,6.1, and 7.3% moisture content (Dwt basis) and hermetically stored for 6 months at 15, 30, and 45C. Seeds were humidified to uniform moisture (13%) prior to monthly evaluations of germination at 27 and 17C and seedling performance under variable soil temperature. The effects of treatments on percentage of germination after 8 days at 27C were highly correlated with percentage of emergence at 10 days after sowing and foliage dry weight at 17 days. Germination at 27C increased from negligible to <90% with progressive increases in moisture, temperature, and time in storage. However, germination decreased within the first month of storing seeds at 45C with >5.1% moisture, and after 3 months seeds failed to germinate even after 8 days of lowering the temperature in the germination environment to 17C. Otherwise, germination inhibition at 27C was attributed to dormancy since most seeds readily germinated at 17C. Dormancy was sufficiently released and optimum overall performance was obtained after 2 months of storing seeds at 45C and 4.2% moisture.     

Soak conditions and temperature following sowing influence the response of maize (Zea mays L.) seeds to on-farm priming (pre-sowing seed soak)

On-farm seed priming of maize (i.e. soaking seed in water overnight, 17 h) in the semi-arid tropics has been shown to improve crop establishment and yield but the benefits can be variable. In previous work, this variation was thought to result from the interaction between primed seeds and conditions in the seedbed following sowing. To investigate this interaction, experiments were carried out under controlled temperature conditions that represented those of seedbeds in the semi-arid tropics. The conditions during seed priming and during subsequent germination and emergence were investigated as potential causes of variable seedling emergence relative to that of untreated seeds. Priming advanced emergence from moist sand cores at 30 °C/20 °C (day/night), reduced emergence at 35 °C/28 °C and delayed and reduced emergence at 40 °C/28 °C. In drier cores (drained 8 days) at 35 °C/28 °C, priming advanced germination time and did not decrease final percentage emergence. These results confirmed earlier field observations that the effect of priming in maize can vary and lead to positive, neutral or negative effects. Priming decreased the optimum and ceiling temperatures for germination, and unlike untreated seeds, the relationship between germination rate and sub-optimal temperature was not linear in all cases. Pre-humidifying seeds did not enhance the effect of priming, but aerating the soak water did. These results indicate that variable results from priming recorded in the field were not due to imbibitional damage, but may result from the negative effects of hypoxia during soaking exacerbated by moist conditions and high temperatures at sowing. These effects differed between seedlots of different cultivars, indicating the importance of selecting more tolerant maize hybrids to reduce variation in response to priming following sowing in the field. The implications of these findings for the use of primed seeds in the field are discussed.     

Effects of light, hydropriming and abiotic stress on seed germination, and shoot and root growth of pyrethrum (Tanacetum cinerariifolium)

Poor germination and seedling establishment are major problems in arid and semi-arid environments, and these characteristics are considered to be important factors in later plant growth and yield. Laboratory experiments were conducted on freshly harvested pyrethrum (Tanacetum cinerariifolium) seeds to investigate the effects of light (influenced by the seeding method) and seed hydropriming on germination, and shoot and root growth at 25 °C. Exposure to light could reduce germination from 52% to 22% and increase the mean germination time (MGT) from 7 to 12 days. The responses of hydroprimed and unprimed seeds to salt and drought stress were determined at osmotic potentials of 0 (distilled water), −0.3, −0.6, −0.9, −1.2 MPa in NaCl and PEG6000. Seed germination and seedling growth were inhibited by increasing salt and drought stress. The germination percentage of unprimed seeds was reduced from 52% to 16% in −1.2 MPa NaCl, and no seeds germinated at osmotic potentials ≤−0.9 MPa PEG. Both shoot and root growth were inhibited at osmotic potentials ≤−0.9 MPa NaCl and ≤−0.6 MPa PEG. Hydropriming shortened the delay of MGT at all osmotic potentials, and improved the germination percentage in distilled water (from 52% to 59%) and resistance to salt stress with nearly double germination (from 16% to 29%) at the highest salt concentration. When non-germinated seeds were transferred to distilled water after 20 days of incubation in total up to 12-15% of NaCl and 25-27% of PEG stressed seeds did not recover. These results show that the inhibition of the germination and seedling growth at the same osmotic potential of NaCl and PEG resulted from drought stress rather than salt toxicity, and that hydropriming is an effective tool to improve the quality of pyrethrum seeds.     

超干贮藏对柱花草种子的影响

以热研5号柱花草为材料,研究超干贮藏对柱花草种子的生理生化变化及超干保存技术指标。结果表明,含水量降至3.17%的柱花草超干种子,经50℃15d人工加速老化后,表现出较强的抗老化能力。贮藏2a 后,超干种子与分别在5℃和-20℃贮藏下的含水量为8.10%的种子相比,它们的发芽率、活力指数等方面均无显著性差异;超干种子与室温贮藏下的对照相比,其电导率降低43.0%、脱氢酶活性增强33.5%、丙二醛积累减少50.0%、幼苗的吸氧量高 33.0%。经超干处理的柱花草种子能显著提高其耐藏性。     

不同浓度配比的PEG、二甲基亚砜和水杨酸引发对玉米种子抗寒性的影响

以玉米杂交种创奇518新种子为材料,以不同浓度配比的聚乙二醇（PEG）、二甲基亚砜和水杨酸组合作为引发剂,采用L₉（3⁴）正交试验设计,通过低温种植处理,研究提高玉米种子抗寒性的3种引发剂的最佳浓度配比。结果表明,不同配比引发处理的玉米种子发芽势、发芽率、苗鲜重、活力指数、过氧化物酶（POD）和过氧化氢酶（CAT）活性均表现出明显差异。以浓度为20%的PEG、浓度为0.5%的二甲基亚砜和浓度为0.007%的水杨酸组合处理种子的发芽率、活力指数最高,幼苗长势整齐一致,POD和CAT较对照有明显提高。     

Effects of saline and alkaline stresses in varying temperature regimes on seed germination of Leymus chinensis from the Songnen Grassland of China

Leymus chinensis is a dominant and most promising grass species in the Songnen Grassland of Northern China. Experiments were conducted to determine the effect of temperature, salinity, alkalinity and their interactions on seed germination. Seeds were germinated at four alternating temperatures (10–20, 15–25, 20–30 and 25–35°C), with saline stress (9:1 molar ratio of NaCl:Na₂SO₄) and alkaline stress (9:1 molar ratio of Na₂CO₃:NaHCO₃). Germination percentage and rate were inhibited by either an increase or decrease in temperature from the optimal temperature range of 20–30°C, and were also inhibited by an increase in salinity and alkalinity at all temperatures. The inhibitory effects of high salinity on germination were greater at 25–35°C, but seeds were subjected to more stress even though the alkalinity was low under this temperature. Recovery percentage was highest at 400 mm salinity at 20–30°C, but only at 100 mm alkalinity, and 25–35°C also resulted in lower recovery percentage under both stresses. Results suggest that saline stress and alkaline stress have different impacts on seed germination and that saline‐alkaline tolerance of L. chinensis seeds is affected by the interactions of temperature and salinity‐alkalinity. Early July sowing in the field is recommended when temperature is optimal and salinity‐alkalinity concentrations are reduced by the high rainfall.     

不同浓度PEG模拟干旱胁迫对玉米种子萌发特性的影响

以广西3个硬粒型玉米品种为材料,设7个PEG浓度（0、5%、10%、15%、20%、25%和30%）处理,分析PEG对玉米种子发芽率、胚根长、胚芽长和贮藏物质运转率等12个萌发特性指标的影响,探究不同浓度PEG模拟不同程度干旱胁迫对硬粒型玉米种子萌发特性的影响,同时筛选模拟干旱胁迫最适宜的PEG浓度。结果表明,PEG浓度增加会延缓种子第一粒发芽、萌发峰值和平均发芽时间;发芽势、发芽率和萌发指数随PEG浓度的增加而呈下降趋势;PEG处理抑制胚根和胚芽的生长,浓度越高,抑制作用越明显;PEG处理抑制子粒中贮藏物质的运转,随PEG浓度的增加胚根干重、胚芽干重和贮藏物质运转率均呈现显著的下降趋势。12个萌发特性指标均可以用于评价玉米种子抗旱性。模拟轻度、中度和重度干旱胁迫时,PEG浓度可分别为5%或10%、15%或20%、25%。     

不同水势环境对大豆种子活力的影响

试验用7种浓度的PEG溶液来创造大豆种子吸水的不同水势环境。结果表明:种子在低渗透势溶液中缓慢吸水比在清水中快速吸水,其发芽势、发芽率、发芽指数和活力指数都明显提高,田间出苗率达极显著差异,同时提高幼苗干重、鲜重。大豆种子在-1.1860MPa的PEG溶液中吸水48小时,种子活力提高。     

Hydrotime analysis of Lesquerella fendleri seed germination responses to priming treatments

Lesquerella fendleri seeds contain industrial oil, which is increased under arid environments. In such environments, the water needed for germination is available for only a short time, and consequently, successful crop establishment depends not only on rapid and uniform germination of the seedlot, but also on its ability to germinate under low water availability. All of these attributes can be analyzed through the hydrotime model (HT). Priming is a method to improve the speed and uniformity of germination. This technique reduces the hydrotime constant (θ_H) and sometimes displaces the base water potential (ψ_b(50)). This would increase the ability of the seed to germinate under low water availability.The objective of this work was to improve (i) the velocity and uniformity of germination and (ii) the ability to germinate under low water availability condition, in seeds of L. fendleri. We also intended to analyze and model changes in the physiological behaviour of the seedlot caused by the application of the priming treatment with seeds sown both in Petri dishes and containers with soil placed in the field.Seeds were subjected to priming in Petri dishes with a solution of polyethylene glycol (PEG) at 5 (P5) or 20 °C (P20). One-half of the seedlot was used for determination of hydrotime parameters by incubation in Petri dishes at 10, 20, and 30 °C, and in water or PEG solutions calibrated to obtain different ψ_a. The remaining one-half of the seedlot was sown in soil containers. Three different water availability treatments were imposed, field capacity or control, 75%, and 50% of the field capacity with the P5, P20, and untreated seeds. The P20 and P5 seeds germinated faster and more uniformly than the untreated (control) seeds under laboratory and field condition. The HT model analysis revealed that the θ_H constant had been reduced and ψ_b(50) had been shifted towards more negative values in both the P20 and P5 seedlots. This behaviour was consistent with the higher germination percentage attained by the P20 and P5 seeds in the field conditions under reduced water availability (i.e., 75 and 50% of field capacity) compared with that exhibited by the untreated seeds under the same situations.     

番橄榄种子育苗的影响因子研究

研究不同成熟度、不同大小果核、不同贮藏期、不同浓度赤霉素处理、不同温度处理对番橄榄种子发芽率、发芽势和发芽指数的影响。结果表明：成熟度高的果实其种子发芽率、发芽势和发芽指数远高于中度成熟和初步成熟的种子;大粒果核种子的萌发率高于小粒种子;种子采摘后不宜立即播种,果核经过120-150 d贮藏,有利于种子萌发,但过长时间保存会影响种子萌发;在本实验条件下,赤霉素对番橄榄种子的萌发没有影响;适合番橄榄种子萌发的温度为20-28 ℃。     

赤霉素、PEG对玉米种子活力的影响

以玉米创奇518陈种子为材料,利用赤霉素（GA₃）、聚乙二醇（PEG）及其复合引发对玉米种子进行处理,研究玉米种子活力的变化。结果表明,不同引发处理间玉米种子的活力指数、发芽势、发芽率及株高均表现出明显的差异。聚乙二醇具有明显提高玉米种子发芽率的作用,赤霉素能够促进植株的生长,提高玉米出苗速度。     

Development of Rice “Seed-Mats” Consisting of Hardened Seeds with a Cover of Soil for the Rice Transplanter

Conventional seedling mats for rice transplanters in Japan are heavy to carry, and much labor is required to collect, wash and store the nursery boxes. In addition, seeding time overlaps with the labor peak in spring. To reduce such labor, we developed a “seed-mat” consisting of hardened rice seeds (Oryza sativa L.) glued onto a molded rice-hull mat with a cover of soil glued on. Seed hardening, which is done by soaking seeds in water at 15ºC for 5 d followed by drying, and heating of the seeds at 50ºC for 5 or 7 d, reduced the time to 50% germination (T₅₀). In dormant seeds, the heating before the hardening enhanced the effect of the hardening more than the heating after the hardening. Seed hardening increased the dry weight of the shoots from the seed-mats. Covering the mat with soil also increased the percentage of seedling emergence, shoot length, number of leaves and shoot dry weight of the seed-mats. The hardened seeds maintained short T₅₀ and 95% or higher germination for 120 d at room temperature. In the seed-mat, the hardened seeds maintained 95% or higher seedling emergence for 208 d. In conclusion, superior seed-mats could be produced using the procedure involving both seed hardening and cover of soil. The seed-mats can be prepared in winter and stored until seedling-raising period in spring. By the seed-mats, seedling mats can be prepared for the rice transplanter without using nursery boxes, which take up storage space and require much labor.     

海南乡土草蔓草虫豆种子的耐干特性

蔓草虫豆叶量丰富,粗蛋白质和粗脂肪含量均较高,各类家畜均喜食,是亚热带地区较好的豆科牧草.幼苗生长迅速,可在较短时间内覆盖地面,为林下间作、水土保持等生态利用.蔓草虫豆为本属地域分布最广的一种,具有热带乡土草的所有独特特点:顽拗性、寿命较短.种子脱水能降低胞内分子扩散、减少活性氧危害,生理生化反应被限制到极点,且不易受...     

干旱胁迫对圆叶决明种子萌发的影响

通过聚乙二醇（PEG-6000）溶液模拟干旱条件,分别对圆叶决明CPI86134与CPI34721种子进行胁迫处理,测定不同胁迫梯度下,发芽率、发芽势、相对发芽势、胚根/胚芽比值等指标的变化情况,据此综合评定两者的抗旱性。结果表明,不同浓度的PEG胁迫环境对圆叶决明种子萌发有显著影响,随着干旱胁迫程度加大,对种子萌发的抑制作用明显增强,活力指数对PEG胁迫的反应更敏感。CPI34721与CPI86134种子萌发受干旱胁迫抑制的程度不同,其中CPI34721较弱,CPI86134相对较强。萌发初期,CPI34721的发芽率、相对发芽率、发芽势、相对发芽势、发芽指数等指标与CPI86134比较都表现出较高的数值。     

马铃薯实生种子萌芽特性的研究

马铃薯实生种子小,能量低,发芽期间能量转化慢;种子需经8～12小时达吸胀饱和,其饱和吸水量占绝对干物重的86％～105％;种子发芽在13～17℃变温和25℃恒温发芽最好,对光暗反应不敏感;贮藏2～3年的种子发芽力最高,室温下贮藏7年丧失种用价值;种子经卅烷醇浸种(50ppm浸4小时)、CO_2激光辐射10秒钟、50～60℃温汤浸种均能显著提高发芽力。α-萘乙酸浸种(10ppm15分钟)对发芽没有显著影响,但可促进幼苗根系发育。