橄榄(Canarium album)种子形态结构与数量性状分析

以福建主栽的橄榄(Canarium album (Lour.) Rauesch.)品种‘长营’种子为材料,观察其成熟种子及不同发育时期种子的形态结构,对数量性状进行测量与统计分析,并运用概率分级建立形态指标的正态分布分级标准。结果显示,橄榄种子表型性状和形态结构变异较大,各数量性状变异系数为6.77%～19.04%,具有丰富的遗传多样性;橄榄种子心室类型有12种,其中三心室占比最高(97.80%);胚数量0～4个不等;经K-S检验,各数量性状符合正态分布,依据各性状可划分为5级分级标准。本研究为橄榄种质的系统学研究提供了种子形态方面的新内容,可为橄榄资源描述的标准化及遗传育种研究提供一定的参考。     

橄榄(Canarium album)种子形态结构与数量性状分析

以福建主栽的橄榄（Canarium album（Lour.）Rauesch.）品种‘长营’种子为材料,观察其成熟种子及不同发育时期种子的形态结构,对数量性状进行测量与统计分析,并运用概率分级建立形态指标的正态分布分级标准。结果显示,橄榄种子表型性状和形态结构变异较大,各数量性状变异系数为6.77%~19.04%,具有丰富的遗传多样性;橄榄种子心室类型有12种,其中三心室占比最高（97.80%）;胚数量0~4个不等;经K-S检验,各数量性状符合正态分布,依据各性状可划分为5级分级标准。本研究为橄榄种质的系统学研究提供了种子形态方面的新内容,可为橄榄资源描述的标准化及遗传育种研究提供一定的参考。     

绒毛番龙眼种子萌发生态特性的研究

就温度、光照、土壤水分条件对绒毛番龙眼 ( Pometia tom entosa( Bl.) Teysm.et Binn.)种子萌发的影响及种子寿命进行了研究 ,结果表明 ,绒毛番龙眼种子萌发的适宜温度为 2 0～ 35°C,最适温度为 30°C;周期性光照条件下的萌发优于全黑暗条件 ;适宜土壤含水量为 2 0 %～ 70 % ,最适为 6 0 % ;在室内自然摊放条件下 ,9d后发芽率减半 ,16 d后完全丧失发芽能力。研究认为 ,目前绒毛番龙眼的濒危状态主要是由于滥砍乱伐和森林破坏造成的 ,由于其种子具有顽拗性种子的一些特点 ,该物种宜采取活体保存的方法 ,以就地保护为主 ,活植物迁地保护为辅。     

光照对绒毛番龙眼种子萌发的影响

在实验室和自然条件下,研究了光照强度和光照时间对西双版纳季节雨林冠层树种绒毛番龙眼(Pometia tomentosa)种子萌发的影响.结果表明:不论是在持续光照还是在周期性光照条件下,3种不同强度光照处理的绒毛番龙眼种子萌发率都很高,均与对照(全黑暗)无显著差异;光照可加快种子萌发速度(降低萌发速率系数),提高萌发指数和幼苗活力指数.人工遮荫有利于绒毛番龙眼种子萌发率的提高,在100%自然全光照(natural sunlight, NS)下萌发率最低(27.8%),而在0.6% NS处理萌发率最高(78.9%);萌发速率系数在全光照下最大,随遮荫程度的增加而降低,萌发指数和幼苗活力指数则随遮荫程度的增加而增大.在遮荫萌发实验中,绒毛番龙眼种子的萌发可能主要受种子脱水敏感性的影响,即强光下剧烈的水分蒸发引起的暂时水分亏缺导致种子脱水死亡或萌发延迟;已经"萌发"的种子也可能因短期水分胁迫而不能生长到"第一对真叶出现"这一萌发标准就死亡,从而降低种子萌发率.在绒毛番龙眼种质资源保护工作中,既要注意避免强光下温度升高引起的种子过度脱水死亡,又要保证提供适宜光照条件以提高萌发质量和幼苗成活率.     

西双版纳热带季节雨林四种珍稀濒危树种种子萌发对脱水和光的响应

绒毛番龙眼(Pometia tomentosa)、琴叶风吹楠(Horsfieldia pandurifolia)、箭毒木(Antiaris toxicaria)和思茅木姜子(Litseapierrei var. szemois)是西双版纳热带季节雨林乔木层的优势树种,也属于珍稀濒危物种。实验研究了4个树种的种子在经过不同脱水水平、人工遮荫条件下的不同光照水平以及热带季节雨林之林下和林窗的萌发特性。结果显示:脱水对于种子萌发特征具有显著影响,绒毛番龙眼和琴叶风吹楠经48h的连续脱水后丧失了萌发能力;箭毒木和思茅木姜子具较强的脱水耐性,经96h的连续脱水后仍具有较高的种子含水量,且种子萌发率分别为15%和33%。干旱季散布的种子比雨季散布的种子具有更强的脱水耐性。遮荫及森林种子萌发试验中,除绒毛番龙眼外,其它3个树种的种子萌发率以及平均萌发周期在不同光水平或生境下差异显著。琴叶风吹楠和思茅木姜子在30%的光照以及林窗中心的萌发率要显著低于低光处理(10%和3.5%光照)和林下,而箭毒木在30%和10%光水平以及林窗中心获得较高萌发率。雨季传播的具有干燥敏感性的种子,可以减少种子由于干燥而引起的死亡。试验结果可以为4种珍稀濒危植物的保护和人工繁育提供一定理论依据。     

橄榄北移试验初报

在广西桂林引种橄榄已能正常开花结果,种子能繁殖后代．后代植株也能正常开花结果．橄榄北移试种获得成功。     

光对热带雨林冠层树种绒毛番龙眼种子萌发及其幼苗早期建立的影响

绒毛番龙眼(Pometia tomentosa)为西双版纳热带季节雨林标志树种,被列为中国珍稀濒危植物。对其开展种子及幼苗生态学研究可为珍稀濒危树种的保护及当地森林恢复提供科学依据。试验采用遮荫试验和野外试验相结合的方法,研究光对绒毛番龙眼种子萌发及幼苗早期建立的影响。结果表明:在遮荫试验30%(林窗中心光)、10%(林窗边缘光)和3.5%(林下光)3个光处理及森林3种生境(林窗中心、林窗边缘和林下)条件下,种子萌发率差异无显著性差异,均达到95%以上,且平均萌发周期小于6 d。3个光处理下的幼苗生长、生物量分配模式及气体交换参数差异显著。30%光下绒毛番龙眼幼苗的根重比(RMR)和茎重比(SMR)最高,10%和3.5%光下幼苗的叶重比(LMR)最高,3.5%光下的叶面积比(LAR)显著高于30%光下。30%光下绒毛番龙眼幼苗的最大净光合速率(P_nmax)、暗呼吸速率(R_d)和光饱和点(I_sat)在3个光处理中均最大,光补偿点(I_comp)则无显著性差异。绒毛番龙眼幼苗具耐荫性,能够在低光环境下长期存活且能缓慢生长;同时具有适应林窗光环境生长的能力,如高的质量相对生长速率(RGR_M)和高度相对生长速率(RGR_H)。林窗的出现是绒毛番龙眼进行成功更新的必要条件,水分可能是限制其幼苗生境选择的另一环境因子。     

冬季扦插法国梧桐的试验

法国梧桐生长迅速,树姿美观,病虫害少,是一种华北南部,华中及华东一带的良好的行道树。在繁殖上历来都采用扦插,惟成活率较低,一般为40—50%;()或有用种子育苗的,用种子育苗成活率仅20%左右,因为法国梧桐种子发芽率甚低,而所育苗木时间较长,一年生仅高2尺左右,要3—4年才能出圃,成本高,花费大,在目前苗木供不应求,劳动力少的情况下,     

青刺果播种育苗技术的初步研究

采用随机区组设计了青刺果不同播种时间和不同播种方法试验,进行青刺果不同育苗方式对比研究。结果表明:青刺果的育苗宜随采随播,其种子出苗率达72.4%,随着种子储藏时间的后移,出苗率显著下降,干藏与沙藏对种子出苗率的影响差异不明显;裸根苗和容器苗苗木生长质量上无明显差别,随采随播到当年雨季造林时(9月)苗木嫩小,不宜上山造林,但容器苗此时可造林。     

钩藤的种子育苗技术

介绍了钩藤的种子育苗技术,种子处理是钩藤种子育苗成功的关键,在此文中作了较详细的叙述。     

Effect of partial drying and desiccation on somatic seedling quality in Norway and Serbian spruce

Somatic embryo quality is still a problem for many researchers. To improve the efficiency of germination, special procedures are used, such as partial drying of somatic embryos at high relative humidity or desiccation in the presence of supersaturated solutions of salt. In this work, cotyledonary somatic embryos of Norway spruce (Picea abies) and Serbian spruce (P. omorika) were placed on culture media (ME or BM-5) to germinate. We found that after 4 weeks of incubation on these media, hypocotyl and radicle growth of control (non-dried) somatic embryos of both species was not adequate to yield seedlings able to acclimatize to greenhouse conditions. Therefore, somatic embryos were partly dried at relative humidity of 97 % or desiccated at relative humidity of 79 %, for 2 or 3 weeks, and then placed on the Margara (ME) medium. Partial drying of somatic embryos at the higher relative humidity (97 %) enabled an improvement of radicle growth of germinating somatic embryos in both species. The highest conversion rate (45 %) was obtained for embryos of Norway spruce maintained for 2 weeks at relative humidity of 97 %. This treatment contributed to the improvement of germination and conversion efficiency of somatic embryos of Norway spruce, regardless of the drying period. Improved radicle growth facilitated development of better quality seedlings of this spruce species. In Serbian spruce, we did not obtain seedlings of sufficient quality, due to poor hypocotyl growth. Desiccation at humidity of 79 % for 3 weeks proved to be lethal to somatic embryos of both species.     

黄山松更新特性与光因子关系的研究

通过对４种透光度下黄山松苗及黄山松与麻栎混播苗连续３年生长、生理指标的定期观测,以及黄山松种子综合测试,探讨了黄山松种群在天然林下更新的机理。结果表明,黄山松种子饱满率６５％,发芽率仅为２７％,综合逆境活力为２６％。较低的发芽率在一定程度上影响了黄山松的繁殖能力。黄山松光合速率受太阳辐射能的影响较大,而受湿度、地表温度影响较小。黄山松光补偿点高,从而导致其林下更新较为困难。由于黄山松苗生长缓慢,针     

Effect of canopy position on germination and seedling survival of epiphytic bromeliads in a Mexican humid montane forest

BACKGROUND AND AIMS: Seeds of epiphytes must land on branches with suitable substrates and microclimates to germinate and for the resulting seedlings to survive. It is important to understand the fate of seeds and seedlings in order to model populations, but this is often neglected when only established plants are included in analyses. METHODS: The seeds of five bromeliad species were exposed to different canopy positions in a Mexican montane forest, and germination and early seedling survival were recorded. Additionally, the survival of naturally dispersed seedlings was monitored in a census over 2.5 years. Survival analysis, a procedure rarely used in plant ecology, was used to study the influence of branch characteristics and light on germination and seedling survival in natural and experimental populations. KEY RESULTS: Experimental germination percentages ranged from 7.2 % in Tillandsia deppeana to 33.7 % in T. juncea, but the seeds of T. multicaulis largely failed to germinate. Twenty months after exposure between 3.5 and 9.4 % of the seedlings were still alive. There was no evidence that canopy position affected the probability of germination, but time to germination was shorter in less exposed canopy positions indicating that higher humidity accelerates germination. More experimental seedlings survived when canopy openness was high, whereas survival in census-seedlings was influenced by moss cover. While mortality decreased steadily with age in juveniles of the atmospheric Tillandsia, in the more mesomorphic Catopsis sessiliflora mortality increased dramatically in the dry season. CONCLUSIONS: Seedling mortality, rather than the failure to germinate, accounts for the differential distribution of epiphytes within the canopy studied. With few safe sites to germinate and high seedling mortality, changes of local climate may affect epiphyte populations primarily through their seedling stage.     

Effects of Temperature on Germination of Peronospora parasitica Conidia and Infection of Brassica oleracea

The effect of temperature on germination of a South African isolate of Peronospora parasitica , and infection of Brassica oleracea was studied. The optimum condition for germination was 20° C at 100% relative humidity. The percentage germination obtained was 80–98% and 70–80% between 15 and 25° C at 100% relative humidity, after a 12 and 6h incubation period, respectively. Optimum temperature for germ tube growth was also 20° C. The temperature range for maximum infection of seedlings of a highly susceptible cabbage cultivar and subsequent disease development in vitro was 15–25° C and 90–100% infection was achieved after 48 h of incubation. At<15°C and 26–30° C infection percentage was decreased to 40–50% and 35–40%, respectively. No disease incidence was recorded at temperatures above 35° C. A scanning electron microscope study of the infection process showed that penetration of cotyledons by germ tubes was mostly via stomata and occasionally directly through the cuticle. Results are discussed in relation to the need for future studies of P. parasitica in South Africa.     

Improved somatic embryo production from embryogenic tissue of Pinus patula

Summary Embryogenic tissue from six genotypes of Pinus patula (Schiede et Deppe) was subjected to a number of treatments to improve both somatic embryo maturation and germination protocols. The use of a slightly modified 240 medium supplemented with polyethylene glycol (PEC) significantly improved both the number and quality of embryos produced, especially at the 7.5 and 10% level. Various pre-germination treatments were tested to enhance embryo germination. A partial drying treatment (PDT) at high relative humidity, lasting approximately 4 wk, gave the best germination results. Despite the beneficial effects of the PDT, embryos that had been harvested from the 240 maturation treatment containing no PEG gave the best germination responses when compared to the PEG-treated cultures. Plantlets were acclimatized ex vitrum, but success rates were low. Latent PEG effects were observed in acclimatized somatic seedlings.     

Laboratory experiments on sugar-beet downy mildew (Peronospora farinosa)

The optimum conditions for Peronospora farinosa betae to produce spores were temperature 8–10 °C and relative humidity 90 % or more, but many spores were produced between 5 and 20 °C and between 80 and 90 % R.H. Most spores were formed in darkness after leaves were exposed to light for 6–8 h. Spores survived exposure to 60 % R.H. for up to 5 days, but were soon killed by temperatures above 20 °C. The germination capacity of spores collected from the field was often very small, but this could not be related to the weather. Most seedlings were infected when inoculated at the growing point and incubated in a saturated atmosphere between 3 and 15 °C for at least 8 h.     

四种植物种子萌发及苗期抗旱性差异的研究

对四种豆科植物种子萌发及苗期抗旱性作了比较研究,结果表示：种子萌发期抗旱笥强的植物其苗期抗旱性亦强。干旱引起组织脱水,植株生长受到抑制,幼苗出现衩始萎蔫时间与细胞膜受害时间一致。四种植物显示萎蔫时土壤含水量明显不同,红豆草为４．８０％、羊柴２．２％、花棒１．７４％、柠条１．５１％．据种子相对发芽率、膜透性变化等生理指标综合评定四种植物种子萌发及苗期抗旱能力次序为：柠条＞花棒＞羊柴＞红豆草。     

Effect of priming treatments on seed germination and seedling growth in bamboo [Dendrocalamus strictus (Roxb.) Nees]

Instances of flowering of bamboo species Dendrocalamus strictus are few and far between which are taken as opportunity by nurserymen to collect seeds for propagation. Germination of seeds is reported to be poor. Therefore, different seed priming treatments were applied to D. strictus seeds collected from Ranchi in order to obtain uniform and high germination. Under laboratory conditions, dehusking of seeds before sowing ensured cent percent germination. Seed priming with KNO₃ 1% solution resulted in 80.4% increase in germination followed by hydropriming by 16 h (73.1% increase). In field conditions, dehusked seeds gave 23.0% germination without any priming treatment. Priming treatment with KNO₃ 1% gave the highest rise in germination (39.1%) followed by hydropriming for 16 h (26.1%). Seeds with their seed coats intact could give germination of 9.5% when germinated without any treatment. A rise of 115.8% in germination was obtained by priming with KNO₃ 1% (final germination count 20.5%). The next best treatment was hydropriming for 16 h (final germination 18.5%, a rise of 94.7%). KNO₃ 1% also induced the earliest and the most rapid germination. When seedlings germinated in laboratory were transferred to soil, all seedlings from all treatments established successfully without any mortality whatsoever. Therefore, it is recommended that seeds should be primed for 8 h with 1% KNO₃ and germinated in laboratory or in farm house under normal atmospheric condition before transplanting the seedlings to soil.     

EFFECTS OF RELATIVE HUMIDITY AND TYPE OF CONTAINER ON THE GROWTH OF F1 HYBRID ANNUALS IN CONTROLLED ENVIRONMENTS

The effects of three levels of relative humidity (40%, 65%, and 90%) and two types of containers (clay and plastic) on the seedling growth of three F₁ hybrid annuals were determined after 14 days of controlled-environment treatment. Forty percent relative humidity was severely limiting to the seedling growth of ‘Blue Blazer’ ageratum (Ageratum houstonianum Mill.), ‘Pink Cascade’ petunia (Petunia hybrida Vilm.), and ‘Double Eagle’ marigold (Tagetes erecta L.). Raising the relative humidity to 65% resulted in striking increases in fresh weight, dry weight, and leaf area, especially when clay containers were used. Height of the main shoot was increased significantly at 65% relative humidity but node number was influenced only slightly. Increasing the relative humidity further to 90% had no significant effect on fresh weight, dry weight, or percent dry weight for any of the three species, in either container. Leaf area was increased significantly at 90% only in ageratum seedlings grown in clay pots. Each species responded differently to the type of container used. The fresh weight and dry weight of petunia seedlings were significantly greater in plastic pots at every level of humidity while those of marigold seedlings were unaffected by the type of container used. Ageratum seedlings, on the other hand, had significantly greater fresh weights and dry weights in clay pots only at 90% relative humidity.     

Asymbiotic and symbiotic seed germination of Eulophia alta (Orchidaceae)—preliminary evidence for the symbiotic culture advantage

Eulophia alta (Linnaeus) Fawcett & Rendle seeds collected from the Florida Panther National Wildlife Refuge (Collier County, FL; FPNWR) were used in a screen of five asymbiotic orchid seed germination media to determine their effectiveness in promoting germination and protocorm development. In addition, 10 fungal isolates collected from the roots of E. alta at sites in the FPNWR, Highlands County (FL), and Goethe State Forest (Levy County, FL; GSF), and a fungal isolate from the roots of Spiranthes brevilabris collected from GSF were screened for their effectiveness at promoting in vitro symbiotic germination of E. alta seeds. After 18 weeks asymbiotic culture, seeds sown on PhytoTechnology Orchid Seed Sowing Medium germinated to a higher percentage (87.9%) and had a higher percentage of protocorms with developing protomeristems (32.7%) than seeds cultured on Knudson C, Malmgren Modified Terrestrial Orchid Medium, ?-strength Murashige & Skoog, or Vacin & Went Modified Orchid Medium. Significantly more leaf-bearing protocorms were observed on PhytoTechnology Orchid Seed Sowing Medium (0.8%) and Vacin & Went Modified Orchid Medium (1.3%) than other media tested. Of the fungi tested, one fungal isolate (Ealt-396) promoted germination to 69.0%, two isolates promoted germination to less than 0.75% and did not support further protocorm development, and eight isolates did not support germination. Seeds co-cultured in darkness with Ealt-396 grew more rapidly than asymbiotic seedlings following germination. In addition, co-cultured (=symbiotic) seedlings continued to develop more rapidly than asymbiotic seedlings upon transfer to 16/8 h light/dark photoperiod. Symbiotic seed culture of E. alta may be a more desirable method of propagation since protocorms develop more rapidly than seeds sown on asymbiotic media. Symbiotic seedlings may be more appropriate for reintroduction to natural areas than asymbiotic seedlings since symbiotic seedlings could serve to inoculate soils with a germination promoting mycobiont.