Destruction of Fraxinus angustifolia and Fraxinus ornus seeds under storage conditions caused by Epicoccum nigrum

During the period of seed storage in 2019, stored Fraxinus angustifolia and F. ornus seeds showed signs of infection and fungus Epicoccum nigrum was isolated from mould and necrotic lesions on the seeds. In order to confirm the pathogenicity of E. nigrum towards F. angustifolia and F. ornus seeds, an experiment that included inoculation of seeds with E. nigrum and the assessment of germinability was performed. The inoculation with E. nigrum strain caused mould to around 20% of F. angustifolia and 58% of F. ornus, necrotic lesions to 96% of F. angustifolia and 92% of F. ornus, and decrease in germinability to 95% of F. angustifolia and 97% of F. ornus seeds. This study presented, for the first time, the ability of E. nigrum to cause high infection rates and reduced germinability of the F. angustifolia and F. ornus stored seeds. The transmission routes and possibilities for preventive strategies were discussed.     

东京野茉莉种子休眠特性的研究

以浙江省遂昌县东京野茉莉新鲜种子为材料,通过对种子透水性、种被机械阻力、离体胚培养、发芽抑制物质提取及种子层积过程中的生理生化变化的研究,并利用赤霉素(GA3)进行发芽前预处理,探讨种子休眠机理及破除方法。结果表明:1)离体胚并无休眠特性,胚外组织中也不存在发芽抑制物质。尽管种子透水性影响其发芽率,但胚乳和种壳的机械束缚是东京野茉莉种子休眠的主要原因之一。2)层积后再机械处理可解除种子休眠。休眠能被赤霉素和(或)低温层积处理解除,说明种子同时存在生理抑制,其休眠类型属于综合性休眠。3)贮藏物质在层积过程中的动员与种子萌发率的提高密切相关,种内可溶性糖含量(R=0.885)、POD活性(R=0.658)与休眠的解除呈显著正相关。4)层积30 d后1 200 mg/L GA3处理的种子发芽率最高,为54%。胚的外覆物控制东京野茉莉的种子休眠,休眠解除的过程伴随种子内代谢水平的提高。     

Effect of different seed treatments on dormancy breaking and germination in three species in arid and semi-arid lands

Seeds of many woody plant species have one of several types of dormancy. They do not germinate unless specific environmental signals are in place or events occur. This study was conducted to evaluate the effects of scarification treatments on seed dormancy and germination of Acacia nilotica (L.) Willd. ex Del., Prosopis juliflora (Sw.) DC. and Dodonaea viscosa (L.) Jacq. The following treatments were applied: T1, untreated seed (control); T2, sulphuric acid (97%) for 45 min; T3, boiling water for 5 min. The seeds were cultured on a Murashige and Skoog (MS) medium after sterilization. The responses of seeds to treatments were compared with each other and with the control treatment. Germination was observed daily for a 30-day period. Results indicated positive responses to treatments, while impermeable seed coats may be responsible for low germination rates in intact seeds as seen experimentally in the untreated control. The highest germination was obtained for P. juliflora and D. viscosa acid-scarified seeds (80.8%-90.8%) and for scarified seeds of A. nilotica (50.2%) boiled in water. The germination indices, i.e., final germination percentage (FG), mean daily germination (MDG) and germination rate (GR), were significantly affected by treatments and species (p<0.01).     

Effects of moist chilling and solid matrix priming on germination of loblolly pine (Pinus taeda L.) seeds

Loblolly pine (Pinus taeda L.) seeds from sources with a mild climate under maritime influence (North Carolina) required shorter moist chilling to achieve maximum germination vigor than seeds from sources with a harsher continental climate (Oklahoma). Solid matrix priming (SMP) for 6 d achieved as much as 60 d of moist chilling to improve rapidity, synchrony and completeness of germination for three of the four families studied. SMP after moist chilling increased the rapidity, synchrony and completeness of germination. The benefit of SMP was greatest for non-stratified seeds and the benefit decreased with length of moist chilling. In general, delaying planting for one week after SMP had minor effects on germination when seeds were kept in the SMP matrix at 4°C. Delayed planting after SMP can increase germination rapidity and synchrony of seeds that have received long moist chilling and reduce the benefit of SMP in non-moist-chilled seeds.     

解除休眠水曲柳种子的再干燥贮藏

以解除休眠的水曲柳种子为材料,研究种子再干燥脱水贮藏的可行性。结果表明:已解除休眠的种子在室温条件下进行再干燥是可行的,干燥处理后种子的萌发率和平均发芽时间没有明显变化;但在5℃条件下再干燥是不可行的,干燥后种子萌发率、发芽指数显著下降,平均发芽时间明显延长。已解除休眠的种子在室温条件下再干燥处理后贮藏16个月内种子的萌发率没有显著变化,但随着贮藏时间的延长种子发芽指数显著下降,平均发芽时间显著延长。已解除休眠水曲柳种子再干燥贮藏后使用KT、GA3和乙烯利处理对种子的萌发都没有明显的促进作用。     

Variable dormancy in seed of Pinus contorta

Seeds of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) collected southwest of Grande Praire, Alberta at three different times and altitudes between August 20, 1984 and August 15, 1985 showed variable responses to stratification. The responses were related to seed ripeness, as judged through evaluations of cone moisture contents, and with the length of time that the cones had remained on the trees. Unripe seeds started to lose germination in the third year after pollination when on the tree. Mature seeds which lost germination by late fall 1984 regained it by the next fall, while most unripe seeds did not. Immature seeds increased their need for stratification over time while mature seeds did not. Seeds should be left on the tree until the end of the third year to insure maximum viability because they do not reach maturity until then.     

华南五针松种子休眠生理的研究

对华南五针松种子的休眠生理特性进行研究表明,种内生活细胞的酶活性低,是导致其休眠的主要原因;外种皮存在抑制物质、种皮的透水、透气性差,对种子的萌发也有一定的影响。低温层积处理60天,能有效地解除种子的休眠。其最适萌发条件是光照下30℃(日)/20℃(夜)变温,其次为光照下25℃恒温。     

An evaluation of scarification methods for seeds of two leguminous trees

Twenty different methods of seedcoat scarification were tested on Gleditsia triacanthos L. and Robinia pseudoacacia L. to find an alternative to acid scarification for these species. For germination testing, nicking or burning were best, and these same methods could be used in small nurseries with adequate labor. For larger quantities, hot water soaks or heat shock soak treatments yielded satisfactory, though lower, germination.     

Effect of sowing date on seedling emergence of species with seeds enclosed in a stony endocarp

The aim of the present study was to investigate the effect of the natural sequence of temperature conditions between the time of seed sowing and their germination on dormancy release of Prunus avium, P. mahaleb, P. divaricata, P. laurocerasus, P. spinosa, Cornus mas, C. sanguinea, and Celtis australis seeds which are enclosed in a hard stony endocarp. According to their collection date, the seeds (with the endocarp) of the above species were sown outdoor in summer, autumn, and winter and the number of emerged seedlings was counted during the following two springs. For all species, the first sowing date was immediately after seed collection and cleaning. In all species, seedling emergence occurred in early spring and dormancy was released only after the exposure of seeds to specific season conditions. The exposure of seeds of all studied species, except C. australis, to a period of warm temperatures prior to winter was necessary for dormancy breaking and germination. Autumn sowing of P. laurocerasus and C. sanguinea seeds, which were collected in summer, and the sowing immediately after seed collection of the rest species, resulted in a maximum percentage of seedling emergence in the following spring.     

北美鹅掌楸种子破眠技术研究

用低温层积处理、低温裸层积处理、赤霉素处理等方法研究北美鹅掌楸种子的破眠技术，结果表明北美鹅掌楸种子经150d低温层积，其发芽率接近80％，而低温裸层积90d，其发芽率就达80％以上。200mg／kg浓度的赤霉素处理种子48h发芽率只有35％，但用赤霉素处理后再对种子进行低温层积，种子萌发速度加快，层积60d其发芽率达到77％。     

Artificial Germination Activation of Dialium corbisieri by Imitation of Ecological Process

Species of the gender Dialium commonly are trees found in Central African rainforests. They produce tasty sugary fruits, feeding numerous frugivores, but are, despite their valuable nutritional value, rarely exploited by humans. A potential reason for this could be the complexity of symbiotic dependence between trees and pollinators, germination activators, and dispersers causing problems in ancestral and contemporary domestication. We investigated Dialium corbisieri reproduction in the Democratic Republic of the Congo, Bandundu Province. Here we give a key for an artificial activation of germination of these trees ecologically adapted to the digestive system of their ape dispersers: By perforation of the impermeable seed coat protection, water assimilation and subsequent activation of germination becomes possible. By this nicking, pretreatment germination increases from 0 to 96%, representing an inexpensive and simple treatment to be used under natural conditions and in developing countries. The use of this mechanical activation for forest management, conservation, and economic use is discussed.     

白腊药剂浸种催芽试验

对白腊种子进行药剂浸种催芽对比试验的结果表明,用５０℃始温温水浸种２４ｈ后,再用浓度为２００×１０－６ｍｇ／ｍｌ吲哚乙酸（ＩＡＡ）浸种３ｈ和同样浓度的赤霉素（ＧＡ３）浸种２４ｈ,其种子发芽率分别达到６４％和６２％,与层积催芽法发芽率基本相当,是理想的白腊催芽方法。     

Influence of light quality on the germination of Betula papyrifera seeds

The influence of light quality on germination of unstratified birch seeds (Betula papyrifera) was investigated in a greenhouse study. Different light regimes were created with five plastic filters of different colour in combination with basic illumination. The filters were adjusted to equal levels of photosynthetically active radiation. The difference in light quality in terms of R : Fr ratio (red : far‐red light ratio) varied from 0.23 to 1.03. Germination was recorded 7, 10, 14, 21, 25, 31 and 36 days after sowing. Response to light quality was significant from 25 days after sowing (p < 0.043), and it was found that differences increased with time. Filters producing light regimes with low R : Fr ratios were found to reduce and delay germination of birch seeds. Germination after 36 days varied from 55% for the control treatment to 11% for the lowest R : Fr ratio. The relationship between seed germination percentage and R : FR ratio was found to be significant (p < 0.017) with an R‐sq value of 88.6%.     

Effect of thermal pretreatment on germination of seeds from different provenances of subalpine oriental spruce (Picea orientalis (L.) Link.) forest in Turkey

We examined the effect of thermal treatment at two temperatures (60 s of 90°C dry heat and 60 min in 40°C hot water) versus control conditions on the germination of oriental spruce (Picea orientalis (L.) Link.) seeds originating from different subalpine provenances. Cutting test results showed that there was wide variation (between 10% and 90%) in filled seed rates. The results revealed that highest germination yield was attained via the hot water treatment. The maximum germination percentages were observed in seeds from “tree 3” in the first tree collective of provenances 1 (85.33 ± 5.77 control; 88.67 ± 7.02 via the hot water treatment; 82.00 ± 10.58 via the dry heat treatment) and 3 (70.67 ± 17.24 control; 88.00 ± 4.00 via the hot water treatment; 86.67 ± 11.37 via the dry heat treatment). The mean germination percentages were significantly different (p-value < .05): percentage values were 32.57% in provenance 1, 23.22% in provenance 3, 12.25% in provenance 4, and 2.82% in provenance 2. Mean germination time of seeds from different provenances and experiencing various pretreatments showed significant variation. The best pretreatment increase in germination rates was achieved via the wet heat method (60 min in 40°C hot water).     

Changes in the biochemical composition and enzyme activity during dormancy release of Cyclocarya paliurus seeds

Cyclocarya paliurus is only propagated from seeds which have pronounced dormancy. Overcoming seed dormancy is an important component of efficient and cost-effective seedling production of Cyclocarya paliurus. Changes in biochemical composi-tion and enzyme activity were investigated during dormancy release. The activities of all the studied enzymes in the stratified seeds increased significantly, compared to those in the control samples. Of the enzymes examined, the activities of protease increased the most (413.8%), followed by peroxidase (278.7%), lipase (161.0%), glucose-6-phosphate dehydrognase (149.1%) and amylase (60.6%) after 8 months of stratification. Crude fat and protein constituted the bulk of the storage reserves in mature seeds of C. pali-urus. Compared with the seeds before stratification, about 45% of the starch, 46% of the protein and 11% of the crude fat were de-pleted during dormancy release of C. paliurus seeds, while the soluble sugar content was enhanced by 101.5% in the germinating seeds. Correlation analysis showed, during dormancy release of C. paliurus seeds, a close positive relationship between POD and G6PDH activity as well as soluble sugar content and amylase activity, while there was a significant negative relationship between storage substances and their related enzyme activities.     

中华结缕草种子解除休眠方法研究

针对中华结缕草深休眠的特性,研究了不同物理、化学等处理方法对中华结缕草解除休眠的作用。结果表明:以700mL·L-1乙醇浸泡3min后,在300g·L-1NaOH溶液中处理20min,再用200mg·L-1GA3浸泡10min效果最好,7d发芽势达89 9%,比对照高出51 9%;16d发芽率达91 0%,比对照高出51 8%,已接近中华结缕草种子的潜在发芽率,发芽历时比对照缩短12d。     

不同处理对木球卢卡树种子出苗的影响

对木球卢卡树种子分别采用8种不同的方法浸种,促进种子出苗。经方差分析表明,各处理间出苗率存在极显著差异。其中,150mg／L赤霉素浸泡24h效果最好,出苗率最高,达到63％-300g／L烟丝水浸泡24h效果次之,达到56％。两种处理方法整齐度都好,存在极显著差异。     

不同处理对凤凰木种子发芽的影响

凤凰木是世界热带地区著名的园林绿化树种,在我国热带南亚热带地区广为栽培,用常规方法育苗,种子发芽率低、发芽不整齐。为了提高凤凰木种子发芽率,采用沸水浸泡、浓硫酸处理以及砂擦种皮等措施,对种子进行播种前处理、催芽。试验结果表明:3种方法均能显著改善凤凰木种子的发芽状况,但以浓硫酸处理效果最好,其发芽率、发芽势最高,分别比对照高4．9倍和11．7倍,且发芽速度最快,平均发芽速度比对照快3 d;其次是砂擦处理,其发芽率比对照高3．4倍;100℃热水处理的效果较差,其发芽率仅比对照高 1.3倍。     

刺楸种子催芽处理试验研究

本文对刺楸种子催芽处理技术进行了试验研究。证明刺楸种子处于生理休眠,其休眠原因在于胚未完成发育。不进行催芽处理,当年不能出苗,种子在催芽过程中,必须先暖温处理,后转低温处理,使之完成生理后熟,才能解除休眠。     

贮藏温度对枫香种子耐贮性的影响

目的 以枫香种子为试材,研究不同贮藏温度下种子活力随时间的变化规律,为枫香种子的贮藏方法提供理论依据。 方法 将枫香种子阴干至含水量为10.54%,然后分别贮藏于室温（25±2）℃、4℃、−20℃和−70℃的温度条件下,于贮藏0、60、180、300、360、520、730 d分别测定种子的丙二醛含量和相对电导率,并将种子于室内播种,测定发芽势、发芽率及播种1个月后萌发幼苗的苗高和根长。 结果 随着贮藏时间的延长,4种温度下种子的发芽率、发芽势、幼苗苗高与根长均逐渐降低,丙二醛含量和相对电导率逐渐升高;贮藏至360 d时,4种温度均能较好地保持种子活力,相互之间差异不明显;至730 d时,4℃、−20℃和−70℃的贮藏效果明显优于室温,−70℃的贮藏效果最佳。 结论 枫香种子在含水量10.54%时,若贮藏时间在360 d以内,则室温贮藏即可有效保持种子活力;若贮藏时间进一步延长,则需要采用低温进行贮藏;贮藏730 d时,4℃、−20℃和−70℃均可有效保持种子活力,其中,−70℃的贮藏效果最佳。