Simmondsins quantification by spectrophotometry UV–vis in press cake and in jojoba seeds (Simmondsia chinensis (Link) Schneider), from Argentina

In this paper, we describe a simple, fast, and efficient method for the quantification of simmondsins and simmondsin's ferulates in jojoba seeds and residual cakes, without using expensive equipment or laborious techniques. Spectrophotometric measurements (UV–vis) were used for the quantification of the content of simmondsins, total ferulates and total simmondsins in jojoba seeds and residual cakes from the provinces of Catamarca and La Rioja, Argentina. The average values of such components found in seeds, in 100 g of dry and defatted sample, were 11.54 ± 0.91 and 2.24 ± 0.28 g of simmondsins and of simmondsin's ferulates, respectively, whereas the respective values in residual cakes were 10.08 ± 0.31 and 2.93 ± 0.64 g, respectively. A great diversity between the simmondsin contents and their ferulates in seed samples of different origins as well as in different clones was observed. The residual cakes did not present differences respect to the simmondsin contents; however, there were some difference with the simmondsin ferulates. These variations are due to the genetic antecedents of plants and the environmental conditions in which they grow.     

Effect of plant growth regulators on floral differentiation and seed production in Jojoba (Simmondsia chinensis (Link) Schneider)

The effect of foliar application of cytokinin (benzyl-adenine, 150 mg L⁻¹) and gibberellin (GA₄ + GA₇, 150 mg L⁻¹) on growth and flower development of 5-year-old plants of two jojoba clones was studied. The plant growth regulators were applied on October 5, 1999 (spring) and the plants were evaluated 120, 240 and 360 days after application. Shoot length, total number of nodes and number of nodes with branching were statistically different between clones but not between the growth regulator treatments.The total number of flowers on both clones was significantly increased by treatment with benzyl-adenine (BA) and significantly reduced by treatment with gibberellin. The seed yields, evaluated 180 days after application, were not statistically different from the control due to an increase in flower abortion. One clone treated with gibberellin showed a significant decrease in number and weight of seeds, the other did not.Histology of axillary buds revealed that BA application on one clone (4.11.32) enlarged the flower meristem, differentiating multiple flower production.     

盐胁迫对不同基因型紫苏种子萌发、幼苗生长 和生理特征的影响

本文对苏引1、紫野7和紫野10三个不同基因型紫苏在不同浓度（0,50, 100, 150, 200,250mmol/L）盐胁迫下种子萌发、幼苗生长、根系活力、丙二醛及可溶性糖含量、过氧化物酶活性等进行了研究。结果表明：种子发芽率、发芽势、种子活力指数等发芽指标均随盐浓度增加而降低。不同盐浓度胁迫下幼苗培养3周后,随盐浓度增加,幼苗株高、幼苗活力指数、存活率、鲜重、干重和根系活力降低,MDA和可溶性糖增加,POD呈先增加后降低的趋势。三个紫苏品种在种子发芽、幼苗生长和生理变化上均表现出不同的耐盐能力,苏引1 耐盐能力最强,紫野7居中,紫野10对盐胁迫最敏感。     

抗旱剂对大豆出苗及幼苗生长的效应

在干旱胁迫下，抗旱拌种剂加浸种剂复合处理能够提高大豆种子的发芽率，促进幼苗根系生长，增加根冠比，加强水分的吸收和利用。同时能提高叶绿素和可溶性糖含量，幼苗体内脯氨酸含量降低，植株保水力明显增强。试验结果表明抗旱剂浸种8h后2％拌种处理效果最好。     

模拟酸雨对花生种子萌芽及幼苗生长的影响

以人工模拟酸雨试验研究不同酸度酸雨对花生种子萌发和幼苗生长的影响，试验结果表明，pH值4．5以下的酸雨可显著地降低花生种子的发芽率，使胚根长度变短，活力指数下降，高酸度的模拟酸雨胁迫使花生幼苗叶总数显著减少，叶片出现明显的受害症状，pH值2．5的模拟酸雨胁迫使叶绿素含量明显下降，过氧化氢酶活性显著增强，酸雨还对土壤具有酸化作用。     

Comparative efficacy of surface drying and re-drying seed priming in rice: changes in emergence, seedling growth and associated metabolic events

In seed priming, seeds are soaked in a solution of low water potential and dried back to their original weight. This study was conducted to evaluate the comparative performance of different seed priming treatments and to investigate whether re-drying is essential or not? Seeds of fine grain aromatic rice (Oryza sativa L.) cultivar Super-Basmati were subjected to hardening, osmohardening with CaCl₂ and KCl (ψ _s ?1.25 MPa) each for 24 h (one cycle), and hydropriming and ascorbate priming (10 mg L^?1) for 48 h. Seeds were primed in two sets. In one set after each treatment, seeds were given three surface washings with distilled water and dried back near to original moisture contents with forced air. In the other case, after surface washings with distilled water, seeds were surface dried using blotting paper and sown immediately. All the priming treatments improved the emergence, seedling growth and reserve metabolism. Use of surface drying was more effective for rice seed invigoration, as evident from earlier and synchronized seedling emergence. Moreover, shoot and root length, seedling dry weight, root score, α-amylase activity, soluble sugars and dehydrogenase activity were also improved, although germination percentage and leaf score were similar from both strategies. Results suggested that surface drying, rather than re-drying close to original weight, was more effective, while among the treatments, osmohardening with CaCl₂ was the most effective. Increasing rice production with judicious use of water is need of the day, and aerobic rice cultivation is an attractive alternative for this purpose. However, poor and erratic stand establishment is one of the major hindrances in its wide scale adoption. In this regard, seed priming techniques are pragmatic approaches to achieve proper stand establishment in the new rice culture. They help in improving seedling density per unit area under optimal and adverse soil conditions and may be opted to improve the performance of aerobic rice.     

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.     

温度和盐胁迫对油葵种子萌发及幼苗生长的影响

通过测定不同温度和盐胁迫浓度对油葵种子发芽势、发芽率和幼苗生理生化特性指标的影响,发现相同温度条件下,随着盐浓度的升高,油葵种子的发芽势、发芽率呈降低趋势,发芽时间延迟,胚根的生长受到抑制,胚根长、子叶鲜重均呈现下降的趋势;油葵幼苗的叶片和根系的电解质相对外渗率,SOD、POD活性均呈现先升后降的趋势.相同浓度盐胁迫下...     

Effect of salt stress on seed germination and seedling growth of three salinity plants

Seeds of three halophyte species included Limonium sinense Kuntze, Glycine soja sieb. and Sorghum sudanense Stapf. were used to investigate the effects of different salinity concentrations on their germination percentage, germination energy, germination index, relative germination rate, relative salt-injury rate, radicle length and hypocotyl length. Results showed that seeds of G. soja can germinate well and rapidly at lower level of salt (< 200 mmol L(-1)), 50 mmol L(-1) salt concentrations is better to S. sudanense, suitable salt concentrations was beneficial to germinate of S. sudanense seeds. Seeds of L. sinense and S. sudanense can germinate at higher level of salt (400 mmol L(-1)). Three plant seeds had different physiological mechanism for germination under salt stress, radicle hypocotyl ratio of L. sinense and S. sudanense increased with increasing salt suggested that they had the higher tolerance in shoot growth under NaCl stress, which is perhaps the reason for their wide utilisation for saline soil rehabilitation.     

3种植物生长调节剂对棉种萌发及棉苗生长的影响

采用药剂浸种回干技术,分析了稀土微量元素、芸薹素、甲哌3种植物生长调节剂浸种处理对棉花种子萌发、出苗及幼钅翁苗生长的影响,以期为棉花生产提供参考.结果表明:1000 mg·L-1稀土微量元素、0.01 mg·L-1芸薹素、50 mg·L-1甲哌对棉花种子萌发和幼苗促生效果较好.     

Mobilizing the seed storage oil in milk thistle(Silybum marianum) can supply energy for seed germination and early seedling growth and apply as TAGs breakdown marker

Milk thistle(Silybum marianum) is a crucial medicinal plant containing a large amount of oil.In the study,the changes in storage oil during seed germination and seedling transition from heterotrophic phases were investigated.The results showed that seed oil decreased from 19.53% to 0.88% on the 7th day of seedling development.Oil hydrolysis continued until the 4th day of germination with a low slope,but then increased the use of oils in seed germination end seedling growth metabolism.The results...     

Environmental factors during seed development of narrow-leaved bird's-foot-trefoil (Lotus tenuis) influences subsequent dormancy and germination

Narrow‐leaved bird's‐foot‐trefoil (Lotus tenuis) is a perennial forage legume adapted to waterlogged and heavy and infertile soils and can replace alfalfa (Medicago sativa) in areas with these soils in Argentina. Its seeds are hard and water‐impermeable but the effects of environmental factors on seed dormancy and germination are not known. The objective was to evaluate the hypothesis that water availability during seed development and maturation affects the degree of hardseededness in L. tenuis by changing seed coat properties, conditioning water uptake through the seed coat; and subsequently affecting dormancy, germination and speed of germination. Seeds were harvested in December/January and in February in both 1993/1994 and 1994/1995 from a permanent pasture of L. tenuis growing in a Hapludol soil in San Miguel del Monte province of Buenos Aires. Environmental conditions of each anthesis‐harvest period were determined. Seeds of each harvest were subjected to chilling, washing and mechanical scarification. After 12 months seeds from each harvest were observed in a scanning electron microscope. The water deficit of the soil and relative humidity were greater in the second than the first anthesis‐harvest period in both seasons. In 1993/1994 the control treatment in December had a higher germination rate than the February control seeds (0·40 vs. 0·20) and a faster germination rate. Mechanical scarification and chilling significantly enhanced the germination rate (0·95) and its speed in seeds of both harvests. Low temperatures significantly enhanced germination rate, starting after 60 d for the seeds harvested in December, and 90 d for the seeds harvested in February. In 1994/1995 the results were similar but both the January and February control treatments had higher germination rates (0·60 vs. 0·40) than in the previous year. Seeds harvested in February were more dormant in both years. These differences could be explained by the conditions in February anthesis‐harvest period in both years that could have hastened the natural dehydration process of seed, changing integument structure and enhancing its impermeability.     

外源海藻糖浸种对低温胁迫油菜种子萌发及幼苗生长的影响

为提高抗寒性,促进油菜种子发芽及幼苗生长,以甘蓝型油菜品种中油杂19为材料,研究外源海藻糖浸种对低温胁迫下油菜种子萌发及幼苗生长的影响,阐明外源海藻糖浸种的寒害缓解作用.结果表明,在低温处理下(10℃),油菜种子萌发受到抑制,发芽势、发芽率、发芽指数及活力指数均显著下降,平均发芽时间显著延长;种子萌发过程中异柠檬酸裂解...     

Changes in wheat seed germination ability,soluble carbohydrate and antioxidant enzyme activities in the embryo during the desiccation phase of maturation

Soluble sugar contents and antioxidant enzyme activities were measured in the embryo of wheat (Triticum aestivum) seeds throughout the desiccation phase of maturation in 2003 and 2004 to investigate whether they were related to seed quality. Whatever the date of harvest after the end of filling, seeds tolerated artificial drying in the ears, and almost all of them germinated at 10 °C whereas they were dormant at 30 °C. Their sensitivity to 5 day accelerated ageing treatment (45 °C, 100% relative humidity) slightly decreased during desiccation. This phase of development was associated with an accumulation of sucrose and raffinose, and an increase in the raffinose/sucrose ratio in the embryo. Artificial drying in the ears resulted in an increase in both sugars, but especially raffinose, and in the maintenance of a high value (around 0.6–0.7) of the raffinose/sucrose ratio. Superoxide dismutase, catalase and glutathione reductase activities did not change markedly in the embryo after mass maturity. They were sufficiently active to maintain malondialdehyde and H₂O₂ contents at very low levels. No clear relationship existed between the antioxidant enzyme activities and seed quality, whereas seed tolerance to ageing seemed to be related to a high value of the raffinose/sucrose ratio.     

Seed availability and gap size influence seedling emergence of dandelion (Taraxacum officinale) in grasslands

Dandelion ( Taraxacum officinale agg.) seedlings colonize gaps in agricultural grassland and give rise to weedy pastures. It was investigated how this colonization is affected by seed availability and gap size. Flowering, seed production and spontaneous seedling emergence in artificial gaps were recorded at seven grassland sites. Fifteen to 126 flowers m⁻² (2·2–18·6 thousands of seeds m⁻²) were produced at particular sites in May 2005. Seed availability explained 0·91 of the between-site variation in seedling abundance. Seedling populations represented c. 0·03 of the seed produced at these sites. Shading, pH, soil nutrients and soil texture did not affect seedling emergence. In 2006, seed was sown at one site in small (33 cm²) and large (400 cm²) gaps on eight occassions during the growing season. Time to germination was on average 10 d shorter and 0·20 more of the seed germinated in small than large gaps, and both varied significantly with date of sowing. Germination was not limited by low temperature. Predation of seeds may have decreased the density of established seedlings. Patches of dandelions in sparse or weakly disturbed grassland are unlikely to disappear spontaneously and repeated cutting during spring flowering is recommended as an effective means of management.     

Involvement of carboxypeptidase in the degradation of the mung bean (Vigna radiata) trypsin inhibitor during germination and early seedling growth

Examination of the substrate specifity of the carboxypeptidase activity of ungerminated and germinated mung beans (Vigna radiata (L.) Wilczek) reveals the presence of two distinct enzymes. The first of these, carboxypeptidase I, is maximally active against carbobenzyloxy-Ala-Phe. It is present in large amounts in the cotyledons of ungerminated seeds, and declines rapidly during germination. The second, carboxypeptidase II, is most active against carbobenzyloxy-Phe-Ala. This enzyme increases in the cotyledons during germination and seedling growth.The possible involvement of one or both of these enzymes in the degradation of the native mung bean trypsin inhibitor (MBTI - F) and its proteolytically modified forms (MBTI - E, - C, and - E') during germination was also examined. The enzyme catalyzing one step in the conversion of MBTI - E to MBTI - C has been isolated with 557-fold purification from germinated mung beans. The inhibitor-degrading enzyme has a molecular weight of approximately 60,000. It is optimally active against MBTI - E at between pH 4.0 to 4.5. No activity was found with MBTI - F, - E', or - C as substrates. The enzyme has been identified as the carboxypeptidase II on the basis of (1) coelution during chromatography, (2) action on synthetic and natural substrates, (3) sensitivity to enzyme inhibitors, and (4) temporal variation during germination. The MBTI degrading carboxypeptidase removes the two carboxyl-terminal residues from MBTI - E to produce an inhibitor species that co-migrates with MBTI - C on polyacrylamide gel electrophoresis, but has not been subjected to the internal cleavage and proteolysis at the amino-terminus found in MBTI - C.Supported by National Science Foundation Grants PCM 8003854 and PCM 8301202Abbreviations used are: TNBS, 2,4,6-trinitrobenzenesulfonic acid; Cbz-, carbobenzyloxy-; PMSF, phenylmethylsulfonyl fluoride; MBTI, mung bean trypsin inhibitor; SDS, sodium dodecylsulfate; PAGE, polyacrylamide gel electrophoresis.     

种子成熟度对黑花生出苗及生育后期光合特性的影响

为明确种子成熟度对黑花生生长的影响,本研究以黑花生品种黔花生七号为试验材料,设4个种子成熟度,采用室内与大田相结合的方式,研究不同成熟度黑花生种子发芽、出苗、生育后期光合特性以及产量的变化。结果表明：不成熟（T1）的花生籽仁作种子,植株长势弱,光合速率低;较成熟（T2）和成熟（T3）的花生籽仁作为种子,其光合同化能力强,光合速率高。随种子成熟度的增加,花生发芽势、发芽率和出苗率均呈先增加后降低趋势,且在T3处理下各指标值最大, T2、T3、T4（过成熟）处理发芽势、发芽率和出苗率均显著高于T1;除结果枝数外,花生产量及农艺性状均随种子成熟度的增加呈先增加后降低的趋势,在处理T3下荚果产量显著高于其他处理。因此,选用成熟的黑花生作为种子,其出苗好,光同化能力强,净光合速率高,荚果产量高。     

向日葵芽期、苗期抗旱性鉴定方法研究

通过室内发芽试验和室外盆栽试验对11个抗旱性不同的油用向日葵育种材料进行研究,测定与抗旱性有关的相对发芽指数、萌发抗旱指数和株高等14项鉴定指标。以种子萌发指数与幼苗成活率的乘积作为灰色关联度分析的参考数列X0,运用灰色关联度理论,分析各指标与苗期抗旱性的关系,从中筛选出关联度较大的相对发芽率、相对发芽指数、芽相对生长量、根相对生长量、苗期株高、鲜重、相对电导率、相对含水量8个指标,然后通过隶属函数法对抗旱性进行分析,定量地评价11个油葵育种材料芽苗期的抗旱性。本研究为油葵芽苗期抗旱性鉴定提供了一套科学的评价方法, 对油葵抗旱育种有一定的实践意义和参考价值。     

Effect of soil solarization on true potato (Solanum tuberosum L.) seed germination, seedling growth, weed population and tuber yield

Summary True potato seed of 17 progenies were evaluated during 2002-03 and 2003-04 crop seasons for 12 characters related to seed germination, seedling growth and weed population in nursery beds and tuber yield of transplanted seedlings under non-solarized field conditions. Solarization was found to have beneficial effect on seed germination, seedling growth and yield of transplanted seedlings. Total weeds and major annual weedCornopus didymus were reduced to a great extent due to solarization. However solarization had no effect onCyperus rotundus. Progenies also showed significant differences among themselves for the various characters studied. The progeny x solarization interaction was also significant for all the characters. Yield increase in present study shows that the approach involving raising of seedlings in solarized nursery beds and subsequent transfer of seedlings to non-solarized field would be cost-effective and profitable for raising true seed crop of potato.