甘孜高海拔地区大果圆柏育苗技术研究

本文分析了大果圆柏的生物学和生态学特性,对育苗环节的苗圃地选择、种子采集、种子贮藏、种子处理、播种时间、播种方式、播种量以及苗木的后期管理进行了叙述。研究结果表明：1）沙藏是贮藏种子的最好方式,各项调查指标均优于其它贮藏方式;2）育苗过程中,应该特别注意夏季的控温和冬春两季的控湿措施;3）大果圆柏种子生长周期长,易受病...     

不同催芽方法和播种期对福建山樱花种子发芽率与幼苗生长的影响

介绍了福建山樱花种子采集和处理方法,并研究了不同催芽方法和播种期对种子发芽率与幼苗生长的影响。结果表明,变温沙藏或冷藏的种子次年春播种的发芽率分别达94.5%和90.03%,变温沙藏的种子当年夏季播种的发芽率达83.8%,均能获得较高的发芽率;采种当年播种的苗木,以变温沙藏的地径和苗高为最大,分别达0.49 cm和24.47 cm,即采即播的地径和苗高为最小;采种次年播种的,以常温沙藏的地径和苗高最大,分别达0.90 cm和77.65 cm。     

Differentiation of seed germination traits in relation to the natural habitats of three <Emphasis Type="Italic">Ulmus</Emphasis> species in Japan

Germination traits of three Japanese Ulmus species, including two summer-fruiting species, U. davidiana var. japonica (UD) and U. laciniata (UL), and an autumn-fruiting species, U. parvifolia (UP), were investigated. Germination tests that controlled light (16 h dark–8 h light/24 h dark) and temperature (alternating 20–30°C/constant 23°C) conditions were conducted just after seed dissemination. Under the preferred (light and alternating temperature) conditions, UD germinated quickly and percentage germination was high (99%), whereas UL and UP germinated moderately to slowly (65.2 and 23.8%, respectively) and the remaining seeds were primarily dormant. When the seeds were exposed to unsuitable conditions for germination, secondary dormancy was induced in all three Ulmus species. Because primary and secondary dormancy of these species was not strict, the existing dormancy could be released by moist conditions and low temperature during the winter. Thus, all three Japanese Ulmus can germinate either just after seed dissemination or in the following spring. Nevertheless, the predominant germination of summer-fruiting UD just after seed dissemination seems to be advantageous for finding safe sites that might become available after a large-scale fluvial disturbance. Similarly, the delayed germination of autumn-fruiting UP until the following spring seems to be advantageous for preventing germination at the end of the growing season. Summer-fruiting UL had a more negative response to favorable light conditions just after seed dissemination, which seems to be advantageous for establishment in canopy gaps. These germination traits seem to be adaptive responses to the dominant disturbance regimes of their natural habitats.     

Scots pine (Pinus sylvestris L.) plantations contribute to the regeneration of holly (Ilex aquifolium L.) in mediterranean central Spain

The aim of this study is to evaluate the recruitment possibilities of holly (Ilex aquifolium L.) populations under Pinus sylvestris plantations in the mountains of Central Spain. Population recruitment of holly under P. sylvestris L. plantations was studied at two localities. We sampled holly seed rain, seed bank, and seedling emergence and survival (of both emerged and planted seedlings) in both localities. Seed germination was analysed by randomly sowing Ilex seeds and their subsequent recollection and analysis over the following 3 years (only in one locality). Seed rain, seed bank and emerged seedling densities did not differ between localities. Seed bank density was between 10 and 20 seeds m⁻², considerably higher than the observed seed rain (0.4–1.2 seeds m⁻²), and also higher than the emerged seedling density (0–4 seedlings m⁻²). But Ilex is not very efficient in germinating under pine forests (29.1% germination after 3 years). This may indicate a seed accumulation process of at least 5 years. Seedling survival for the first year differed among the studied sites (50–60 vs. 17%). Nevertheless these survival rates are higher than those found for the same seedling populations in different forest habitats (not Scots pine forests) from near locations. Differences in summer water stress between the study sites are proposed as the main cause of the observed differences in seedling survival. It is concluded that P. sylvestris forests may provide one of the best regeneration habitats for holly in the Mediterranean area, where this species is close to the Southern limit of its distribution.     

Mechanical but not physical dormancy is a cause of poor germination in teak (Tectona grandis L.f.)

Poor seed germination is a significant problem for propagation of teak and it particularly hampers the deployment of genetically improved material into plantations. Seed dormancy is the putative cause for delayed and sporadic germination of teak seed but specific dormancy mechanisms have not been proven. In this paper we investigate whether physical or mechanical dormancy could affect teak germination. Physical dormancy was disproved when we observed water in every examined locule of fruit which had been immersed for 12–24 h (n = 1,700 fruits from six diverse sources). Mechanical dormancy was found to affect teak seed germination by means of valve structures which must open for the radicle to emerge. All 1,450 germinating seeds in 16 samples emerged from the endocarp via the detachment of a valve. Germination over 16 days was compared between extracted seeds (ex situ) and seeds within their endocarp (in situ) to determine the effect of mechanical dormancy on germination. Significantly greater germination of the ex situ seeds (62 ± 2% SE; n = 486) than of the in situ seeds (32 ± 2% SE; n = 564) indicated that mechanical dormancy is an important factor in the poor germination of teak.     

Germination traits and adaptive regeneration strategies of the threeCarpinus species

Germination tests in the three sympatricCarpinus species,C. laxiflora, C. tshonoskii, andC. cordata, were carried out to clarify their germination traits in relation to the regeneration strategies. Seeds did not germinate just after ripening under any conditions in the three species. After one or two rounds of cold stratification, however,C. laxiflora andC. tshonoskii showed high germination percentages (>80%) at alternating temperature in light whileC. cordata did not. After a long-term (10 months) cold stratification, about 100% ofC. cordata seeds germinated, although about 70% of these seeds were in “conditional dormancy” and cannot germinate in the dark. Seed germination in the threeCarpinus species was enhanced by alternating temperature, but not by light exposure. These results suggest that the seeds of the three species are dormant just after ripening and the dormancy is broken by cold stratification. with intra-generic variations in the breakage. Germination traits in each species may be closely related to the regeneration strategy;C. cordata maintains a persistent seed bank with seed dormancy and regenerates after disturbances as a seed bank strategist, whereas the other two species germinate in the next spring after seedfall and regenerate depending either on existing disturbed-sites or sites of recent disturbances after seedling establishment as a seed rain strategist (C. tschonoskii) or seedling bank strategist (C. laxiflora). This study was supported by grants from the Ministry of Agriculture, Forestry and Fisheries (BCP-97-III-A).     

不同降雨型桉树种苗期特性研究

以新引入四川的20个桉树品种71个种批号种子为材料,开展了育苗试验及苗期生长发育特性观察,重点观察了分别代表冬雨、夏雨、均匀降雨型的品种王桉、大花序桉、白腊树桉的苗期特性。结果表明:不同品种种子萌芽所需的温度、湿度是不一致的,在相同的温湿度条件下,各个品种发芽期、发芽率不同,但苗期发育特性基本相同。苗木的个体发育前期是根的快速生长,苗木高、地径、根的生长量随叶片数量增加而增加;夏季播种的夏雨型品种和部分均匀降雨型品种出苗整齐,出苗率一般在85%左右;冬雨型品种发芽极不整齐,发芽期从8月延续到翌年3月。同一品种秋季和初夏育苗的效果也不一致。     

Seed biology and germination ecophysiology of Camellia nitidissima

Camellia nitidissima Chi (Theaceae) is a famous ornamental species with golden-yellow flowers. Due to deforestation and destructive collection of seedlings, its natural population size has been reduced greatly in recent decades. To provide basic information for its conservation, we studied the morphological and physiological characteristics of seeds and the environmental factors influencing germination. The seed production of C. nitidissima was of low yield, which caused lack of seed resource. The seeds were big and heavy, so they did not spread far from the mother trees and did not enter soil after falling down. Optimal temperatures for seed germination were 25–30 °C. The fresh-harvested seeds had high moisture content and weak desiccation-tolerance, so they tended to be recalcitrant. Soaking for 24 h in 10–30% PEG solution could significantly reduce the seed germination percentage. The imbibed seeds placed on the soil surface mostly could germinate, but some of them could not develop into seedlings because the embryo roots did not grow into soil. When the seeds were sowed at the depth of 1 cm, the seedling emergence reached over 70%, but then decreased with increased sowing depth, and reached about 50% when at the depth of 5 cm. The seeds sowed in sandy soil had higher emergence than those in clayed soil. It is feasible for seedling nursing to harvest seeds in time, harvesting prematurely or postmaturely may reduce seed quality.     

花梨木引种试验播种育苗技术研究

对花梨木进行播种育苗试验,研究播种时不同的种子处理方法、不同的播种时间对花梨木发芽、成活及苗木生长量的影响,结果表明,采用温水浸种和冬季播种可提高种子发芽率,冬播种子的平均发芽率达32%;花梨木冬播苗1年生平均苗高120 cm,平均地径0.5 cm,分别是春播苗的1.33倍和1.43倍。因此,花梨木进行播种育苗采用温水浸种和冬季播种,苗木的生长要好于春播苗。为今后花梨木的播种育苗提供参考。     

Variation in germination character of Robinia pseudoacacia L. (Leguminosae) seeds at individual tree level

To demonstrate the seed dormancy and germination characters of Robinia pseudoacacia L., an exotic tall tree species in Japan, we applied scarification, cold stratification, diurnal thermal regime, heat shock, and/or winter weathering treatments to the seeds. These characters differed markedly among three seed sources (Trees K, B, and I). Scarification revealed that most seeds from Tree K showed physical dormancy, whereas those from Tree B had no physical dormancy. The seeds from Tree I showed weak physical dormancy so that the seeds eventually germinate without any treatments as time goes by. The physical dormancy in Tree K was broken by a long, high heat shock treatment. The results imply that seeds from Tree K respond to fire in natural conditions. Seeds from Tree I responded to a wide range of thermal regimes, except for long, high heat shock. In contrast, most seeds from Tree B absorbed water during cold stratification and some germinated. However, many seeds from Tree B died in the soil during the winter, presumably because of microbial and fungal infections. Seeds from Trees I and B acquired physical dormancy by weathering during the winter, implying that seedpods that remain in the crown function as an aerial seed bank. R. pseudoacacia may be able to produce various levels in dormancy with respect to the winter condition.     

东北地区刺楸种子解除休眠及催芽育苗的研究

通过不同试验材料、GA₃应用和变温层积催芽对比试验,对刺楸种子解除休眠进行研究的结果表明:鲜种+GA₃+(15℃,30 d;冷冻,90 d;-4～0℃,90 d)处理方法发芽率达到90.2%,出苗率达到81.5%;气干种温水(72 h)+GA₃+(13～18℃,90 d;0～4℃,90 d)处理方法发芽率达到76.3%,出苗率达到66.4%。采用鲜种进行变温催芽处理对刺楸种子发芽率、出苗率和1年生苗木质量提高具有显著作用(p<0.01和p<0.05)。研究表明,刺楸种子属于形态-生理休眠类型,采用鲜种+GA₃+变温层积催芽的综合处理方法能有效解除刺楸种子休眠。     

野生毛冬青的驯化繁育研究

毛冬青(Ilex pubescens) 是我国南方常用中药,药材来源主要为野生资源。文章通过引种野生 毛冬青,开展繁育方面的初步研究。结果表明,毛冬青种子具休眠性,导致出苗不齐;采种时间为 10— 12 月,可用随采随播方式播种,播种后约 67 d 开始出土,春季发芽率约 20%,采用低温沙藏略可提高种 子发芽率。毛冬青当年苗平均苗高 33.24 cm,平均地径 4.08 mm,速生期为 5—10 月,苗高 Logistic 拟合 曲线为 y=34.710/(1+66.416exp-0.638× 月份)。毛冬青苗期采用搭棚遮荫（50% 光照）对苗木的生长有利,平均 苗高、地径、苗木存活率、合格苗率比全光照增加 5.81 cm、0.7 mm、16 及 26 个百分点。     

山苍子种子育苗试验

针对山苍子种子休眠期长,苗木繁育困难的现状,采用7月采的种子和9月采的种子进行种子育苗试验。结果表明:7月采的种子的出苗数和苗高生长量只有9月采的种子的20%和63.3%,两者达到极显著差异。7月采种,由于种子尚未完全成熟,种子发芽率低,苗木生长较差;9月采种,种子已完全成熟,种子发芽率高,苗木生长较好。     

Effect of different pre-sowing seed treatments on the germination of <Emphasis Type="Italic">Leucaena leucocephala</Emphasis> (Lam.) and <Emphasis Type="Italic">Acacia farnesiana</Emphasis> (L.)

Leucaena leucocephala and Acacia farnesiana are tree species used for several agricultural purposes in the Mediterranean region. The seeds of these species exhibit dormancy, causing delayed germination. Two experiments were conducted to investigate the effect of pre-sowing treatments (scarification, hot water, or soaking) on seed germination of L. leucocephala and A. farnesiana. In one experiment, seeds were exposed to three pre-sowing treatments: control, sandpaper scarification, or soaking in 70°C water for 4, 8, 12, 16, 20, or 24 min. In another experiment, seeds were soaked in 70°C water for 20 min, and then soaked in water at room temperature for an additional 24, 48, or 72 h or blade scarified. In general, soaking the seeds of the two species in hot water was more effective in breaking seed dormancy than scarification. Sandpaper scarification was not effective for either species. Blade scarification increased A. farnesiana seed germination to 56%, indicating that seed dormancy was mainly a consequence of hardseededness. L. leucocephala seeds collected from Jordan University of Science and Technology (JUST) site and soaked in 70°C water for 20 min and then soaked for 24, 48, or 72 h had germination rates above 97%. Our results suggest that blade scarification of A. farnesiana seeds and soaking of L. leucocephala seeds in 70°C water for 20 min are effective treatments to break seed dormancy and enhance seed germination of these vital species.     

Optimal germination condition by sulfuric acid pretreatment to improve seed germination of Sabina vulgaris Ant.

Understanding the germination traits of plants is important not only for understanding natural regeneration processes but also for developing seedling production techniques for planting. Sabina vulgaris Ant. is a common species used for reforestation in semi-arid areas of the Mu-Us Desert, in Inner Mongolia, China, but its extremely low germination rate, both in situ and in vivo, is a bottleneck for seedling production. Sulfuric acid pretreatment was applied to improve germination, and the germination rate was compared for different soaking time (10, 30, 60, 90, and 120 min), different temperatures (10, 15, 20, 30, and 35°C) and under different lighting conditions (dark and light). Sulfuric acid treatment gave a high germination rate, reaching 60% at 30 days after sowing. However, the non-treated seeds produced no germination. The optimal treatment time in sulfuric acid was 120 min. Germination after sulfuric acid treatment increased at incubation temperatures from 10 to 30°C, but decreased at 35°C. Incubation at 25–30°C gave maximum germination of more than 50%. Light treatment had little effect on germination. Pretreatment with sulfuric acid improved water absorption by the embryo by creating cracks and cavities in the seed coat tissue. These results indicated that S. vulgaris seeds have physical dormancy caused by their hard seed coats, which prevents absorption of water into the embryo. A combination of pretreatment with sulfuric acid and incubation at 25–30°C was most effective in improving the germination of S. vulgaris seeds.     

Restoring dry Afromontane forest using bird and nurse plant effects: Direct sowing of Olea europaea ssp. cuspidata seeds

To identify the perspectives of seed sowing for reforestation of degraded dry Afromontane savanna in exclosures in northern Ethiopia, seeds of a fleshy-fruited, secondary climax tree, Olea europaea ssp. cuspidata, were placed under two pioneer shrub species (Euclea racemosa and Acacia etbaica) and in open microhabitats. Seed removal and germination rates were examined. The effects of bird ingestion, manual pulp removal and mechanical endocarp treatments on germination rates were also studied.

Pulp removal promoted seed germination, in particular in seeds without endocarp manipulation. Seed removal, presumably by rodents, was concentrated in narrow strips along linear soil conservation structures, and not different between shrubs and open microhabitats. In the absence of water stress, humus types did not have a significant effect on germination rates. Under field conditions however, germination was higher under Euclea canopies. The observed facilitative effect of Euclea shrubs on germination may be attributed to moisture retention effects, related to the deep humus layer and canopy architecture, preventing desiccation and promoting imbibition of seeds. When readily available Olea seeds are not used for seedling production, direct sowing of seeds in the humus under dense Euclea shrubs could offer a cheap complement to planting of nursery-raised seedlings for forest restoration projects in recovering Afromontane savanna.     

酸枣种子特性及引种栽培初报

在吉林省柳河县进行酸枣种子育苗及引种栽培试验,结果表明:酸枣种子本身不存在休眠现象,坚硬的内果皮是限制种子萌发的主要因素;酸枣有性繁殖时,需将种实进行低温沙藏90～120 d,发芽出土整齐,发芽率高达91％ ～95％.酸枣1年生播种苗需要埋土防寒越冬,2年生留床苗不需任何防寒措施就能安全越冬,2年生留床苗平均苗高80.6 cm,平均地径0.94 cm,保持了原有的优良形状;适应性强,抗旱、耐寒、抗病虫害能力强.     

青钱柳种子赤霉素处理育苗研究

为了研究青钱柳种子破除休眠,提前播种出苗的方法。采用赤霉素不同浓度溶液对青钱柳种子进行"浸泡后直接播种"、"浸泡并沙藏后播种"2组种子处理育苗试验。结果表明:浸泡后直接播种没有打破种子休眠,播种当年出苗率为0,第2年才出苗;浸泡并沙藏后播种能打破种子休眠,播种第1、2年均出苗,总出苗率13.54%~28.13%,第1年出苗率2.08%~5.21%,占总出苗率的9.1%~27.8%。其中,赤霉素500、750 mg/L浓度溶液浸泡及沙藏处理后,破除种子休眠效果明显,当年出苗率为5.21%,依次占总出苗率的23.8%、27.8%,是适宜的种子处理溶液浓度。     

山楂种子抑制物质的提取分离及生物测定

为了更深入地了解山楂种子的休眠机理,以野生山楂种子为试材,用80%的甲醇溶液对其内果皮、种皮和种胚进行浸提,然后测定提取物对白菜种子发芽的影响;将浸提物分离成A、B、C、D、E、F、G共7相,浓缩后分别测定其对白菜种子发芽的影响。结果表明,山楂种子的内果皮、种皮、种胚均含有发芽抑制物质,其抑制作用依次减弱。7个分离相中除了种皮的A相及内果皮的G相对白菜种子发芽没有影响外,其余各相均显著抑制发芽。     

Roles of gibberellins and abscisic acid in dormancy and germination of red bayberry (Myrica rubra) seeds

Intact seeds from freshly harvested fruits of Myrica rubra (Sieb et Zucc.) were dormant and required 8 weeks of warm stratification followed by 12 weeks of cold stratification for germination. Exogenous application of gibberellic acid (GA(3)) to intact fresh seeds was effective in breaking dormancy, with > 70% of seeds germinating when treated with 5.2 mM GA(3) and incubated at a day/night temperature of 30/20 degrees C for 20 weeks. Removing the hard endocarp or endocarp plus seed coat of fresh seeds promoted germination, and addition of GA(3) to the embryo accelerated germination. The gibberellins GA(1) and GA(4) were more effective than GA(3) in promoting germination of seeds with the endocarp removed. Endogenous contents of GA(1), GA(3), GA(4), GA(7) and GA(20) were quantified by gas chromatography-mass spectrometry-selected ion monitoring in the endocarps, seed coats and embryos of fresh seeds treated with 5.2 mM GA(3). The content of GA(3) decreased in the endocarp during incubation, whereas GA(1) contents increased in the endocarp and seed coat. A high GA(1) content was detected in the endocarps and embryos of newly germinated seeds. We speculate that GA(3) was converted to GA(1) during incubation and that GA(1) is involved in seed germination. Endogenous abscisic acid (ABA) contents were measured in fresh seeds and in warm and cold stratified seeds. The ABA content in fresh seeds was distributed in the order endocarp > seed coat > embryo, with the content in the endocarp being about 132-fold higher than in the seed coat and embryo. Total ABA content of seeds subjected to warm or cold stratification, or both, was 8.7- to 14.0-fold lower than that of fresh seeds. Low contents of endogenous GA(1), GA(3), GA(7) and GA(20), but elevated contents of GA(4), were found in the seed coats and endocarps of warm plus cold stratified seeds and in the seed coats and embryos of newly germinated seeds. These observations, coupled with the finding that GA stimulated germination of dormant Myrica seeds, provide evidence that endogenous ABA inhibited release of dormancy and that endogenous gibberellins, especially GA(4) or GA(1), or both, are involved in germination.