种子重量和出苗率对自由传粉的花旗松家系早期生长的影响

观测记录了39个自由传粉的花旗松(Pseudotsuga menziesii var·menziesii[Mirb]Franco)家系的种子重量、出苗时间和苗木大小的三项标准,以便估算种子重量和出苗的家系变异及种子特性对苗木早期生长的影响。试验采用未发芽种子和萌芽种子播种,以测定用发芽种子播种能否降低种子对苗木早期生长的影响。为了评估竞争对种子重量与苗木大小、出苗率与苗木大小的关系的影响,各家系以密植混合家系区、密植纯系区、稀植非竞争区方式单株播种。结果表明:各家系在种子重量、出苗率、出苗速度方面差异显著,但种子重量与出苗率、种子重量与苗木大小、出苗速度与苗木大小间的相关关系不显著;用发茅种子播种不能降低种子对苗木早期生长的影响;家系间的竞争对增大种子效应也没有多大影响。     

国外松壮苗培育技术总结

本文综述了国外松苗木质量的评价因子,对几项育苗技术试验结果进行总结,种子大小和重量与种子发芽速度相关,早发芽幼苗在苗床上拥有生长空间优势,经种子分级,采用大,中粒种子育苗能够提高苗木质量,根据苗木质量评价和造林表现及育苗经济综合分析,提出国外松适宜的育苗密度为１１０－１４０株／ｍ＾２苗木切根改善根系质量和苗木结构,显著提高造林成活率和改善苗木生长,在亚热带地区,宜在８－１０月份实施２－３次,深度１     

用隔年苦楝种子培育壮苗

我们在苦楝育苗过程中了解到由于苦楝果核坚硬,播种后分化时间长,种子发芽出土迟,苗木生长期短,影响高、粗生长。为了提高苦楝苗的质量,我们于一九六九年进行了隔年苦楝子(果核经一年时间沙藏)育苗试验。结果隔年种子比当年种子提早出土近一个月,种子发芽整齐,苗木生长均匀。     

印度长叶松(Pinus roxbu Rghii)种子重量对发芽和生长的影响

关于种子大小对作物生长的影响,在大田育苗方面已有广泛的研究(Kiesseib-ack,1924;Kautmann and Macfadden,1963;Harper and obeid 1967 and Gei-mond,1972).他们发现种子的大小与作物健壮生长有着密切的关系.但对于许多森林树种的研究尚处于初期阶段.然而,Suprr在1944年就报道了东方白松种子重量,与其发芽、生长和植株早期大小的关系.Griffir(1974年)发现用辐射松大粒种子播种育苗,其苗高比用小粒种子的苗大高18%,重大45%(以烘干重为准).     

南酸枣育苗技术

对南酸枣(Choerospondias axillaris)的育苗技术进行研究，包括南酸枣的采种期、种子成熟特征、种子调制、种子形状及大小、种子千粒重、优良度、苗木生长量和育苗期的安排、苗期施肥试验、育苗基质及容器规格试验，苗木分级等。     

五莲山野生杜鹃薄沙床播种育苗技术

该技术采用薄沙床播种育苗,很好的解决了微粒种子发芽对水分和土壤通透性的要求,解决了覆土厚度难以掌握的问题,满足了每粒种子发芽所需要的条件,使种子发芽率和苗木成活率提高,单位面积产苗量大。种子发芽后,根系很快就能接触到沙层下的育苗基质,及时满足了苗木生长对养分的需求,不需要进行芽苗移栽,减少了对幼苗的伤害,延长了苗木生长的时间,有利于提高苗木的质量和产量,创造最高的效益。     

蚊母树育苗技术研究

通过在云南林林自然中心苗圃对蚊母树进行育苗试验，对蚊母树的生产育苗技术进行探索，归纳总结了蚊母树的生产育苗技术，包括采种期、种子千料重、育苗地的准备、播种方法、种子发芽过程、场圃发芽率、苗木生长量与育苗期的选择、苗木分级、种植密度、产苗量、播种量、播种后及苗期的管理、培育地苗和培育营养袋苗的差别、病虫害防治技术等项。     

瓜栗种子重量对发芽和生长的影响

关于种子大小对作物及林木生长的影响,国外已有很多研究报道,Suprr在1944年就报道了东方白松种子重量与其发芽、生长和植株早期大小的关系。恰汉,雷纳,1980年报道了印度长叶松种子重量对发芽及生长的关系。这方面的研究国内报道不多。瓜栗(Pachira macrocarpa Walp.)是木棉科的一种半落叶性小乔木,种子含可食用油43.57％,目前确认为是一种很有发展前途的木本油料植物。自从国外引入我国     

北美红杉种子育苗试验

对不同种源的北美红杉种子作不同试剂浸种处理和控制不同发芽温度的发芽试验，以及开展不同种种子的播种育苗试验，结果表明：种子发芽率和发芽势最好的方案是用SYA6种源，种子经1000mg/L的KMnO4溶液浸泡12h，发芽温度采用20℃。参试的3种因素中，种源因素对种子发芽率和发芽势影响显著；北美红杉各个种源苗木生长迅速，1年生苗木除苗木侧根数外，各种源间苗木的苗高、地径、主根长度、苗木鲜重和苗木干重差异极显著。     

钩栗人工育苗技术研究

采用随机区组设计钩栗不同年龄母树种子品质、不同播种方式育苗试验,进行钩栗人工育苗对比研究.结果表明:不同年龄钩栗母树种子产量和种子品质存在显著差异,25a生母树种子品质高于45a生母树种子,因此育苗宜选择20～30a生健壮的母树采种.不同播种方式育苗的苗木生长和苗木质量无明显差异.la生幼苗发育可分为出苗期、幼苗期、速生期、苗木硬化期.苗木速生期有3个生长高峰,每个生长高峰依次表现为苗高生长、冠幅生长、地径生长.大田育苗苗木分级表明,Ⅰ级苗率22.8%,Ⅱ级苗率54.6%,Ⅲ级苗率22.6%.     

Effect of seed mass on emergence and seedling development in Pterocarpus marsupium Roxb.

We investigated the effect of seed mass on emergence, seedling survival and growth ofPterocarpus marsupium Roxb., a medium to large, commercially valuable and deciduous tree species. Among the three size classes viz. small （10-12 mm）, medium （13-15 mm） and large （16-17 mm）, the maximum proportion, of seed by number （54.12%） and dry weight （51.87%） was recorded, in the medium size seed class. Seed length and seed width were greatest in the large seed class （16.50 mm, 7.33 mm） followed by medium （13.50 mm, 5.60 mm） and small （11.37 ram, 3.66 mm）. Similarly, hundred seed weight （100 sw） varied from a maximum of 12.92 g in the large seed class to intermediate 10.95 g in the medium seed class and minimum of 7.02 g in the small seed class. The large seed size showed maximum emergence and shoot length over the medium and small seed class. After six months of growth, significant variations due to seed size were also observed for the growth and dry weight of P. marsupium seedlings. Seedling vigour, expressed in terms of height, collar diameter, number of leaves and dry biomass, was sig- nificantly affected by seed class. Seedlings that emerged from large seeds showed better growth and produced heavier seedlings as compared to medium and small seeds.     

The seed weight did not affect first year's bud‐set in Picea abies

Seeds from each of six full‐sib families of Norway spruce were separated into fractions of light and heavy seeds. The mean difference in 1000 seed weight between the two lots within families was 1.6 g. The terminal bud‐set after the first growth season was assessed in a nursery test. No significant differences between the seedlings from the light and heavy seed lot fraction within full‐sib families were found. No relationships were observed between the 1000 seed weights of the lots and the mean bud‐sets of their seedlings.     

栓皮栎种子及苗期种源变异分析

收集了栓皮栎主要分布区12个种源的种子,对种子及播种苗进行了测定分析.结果表明,栓皮栎种子的大小、质量、发芽率及苗期的生长,在种源间均存在显著差异.栓皮栎中心分布区域种源的种子相对较大,发芽率较高,来自这些区域的种源苗期生长亦较旺盛.苗期生长的显著差异表明,栓皮栎种源间及种源内优良类型选育具有很大潜力.     

Absolute and relative growth of Douglas-fir seedlings of different sizes

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings of a single seed source were grown in a bare-root nursery for two years to produce five different stock types by varying spacing and transplanting treatments. They were then planted in the forest together with one-year-old container seedlings of the same seed source, which constituted a sixth treatment. Stem volume mean relative growth rate (R(v)) was low immediately after planting for all stock types except the container seedlings, and increased over the following 7.6 years. An 8-week greenhouse test of the six stock types showed that dry weight mean relative growth rate (R(w)) generally decreased with seedling dry weight, but this effect was less obvious after planting, because only the three smaller stock types showed a decrease in R(w) with size. In another experiment, bare-root Douglas-fir seedlings were grown at five different spacings in a nursery for two years, and seedlings from each spacing treatment were sorted into large or small by height. The resulting 10 treatments were planted in the forest and stem volumes determined over 6.7 years. The linear effect of nursery spacing on stem volume was no longer evident 3.6 years after planting, but large seedlings had greater stem volume than the small seedlings throughout the 6.7 years of the study. There was no indication that R(v) declined with time, but small seedlings had higher R(v) than large seedlings. Relative growth rates of two-year-old Douglas-fir were depressed for a year or two after planting, but then remained relatively constant, or increased during the ensuing 5 years. Relative growth rates of smaller seedlings were greater than those of larger seedlings so that relative biomass differences decreased with time, and the time advantage (the time necessary for small seedlings to reach the present biomass of large stock) of larger stock decreased. Absolute size differences increased with time.     

Seed mass effects on performance of Pinus halepensis Mill. seedlings sown after fire

Pinus halepensis is a widely distributed species in the Mediterranean basin. It is generally well adapted to regenerate after wildfire, except when fire intervals are too short (≤15 years). In these latter situations, direct seeding could be a good alternative for restoring pine woodland after fire. Under dry climate, low seedling growth and survival can greatly limit the use of seeding. Early studies have shown that seedlings grown from large seeds have higher seedling establishment, growth and survival. Seed size grading may however reduce the genetic diversity of a seed lot by eliminating part or all of the families with relatively small seeds. An alternative to improve seed lot quality without losing genetic variability could be collecting and sieving seeds from each family separately. In order to explore the influence of seed mass on P. halepensis seedling performance, seeds from five half-sib families differing in mean seed mass were sown under greenhouse and field conditions. Final seedling emergence was unrelated to seed mass and half-sib family. The time of emergence was also unrelated to seed mass but it varied among families. Seed mass showed a positive effect on seedling height and diameter, both at population level and within family throughout the study period (9 months under greenhouse conditions and 20 months under field conditions). We also observed a negative relationship between seed mass and relative growth rate for seedling diameter, but it was not high enough to fully compensate the initial differences due to seed mass at the end of the 20-month study period. Seedling predation had a considerable impact on seedling survival, and it was not related to seed mass. When seedlings killed by predation were excluded from the survival analysis, larger seedlings, coming from larger seeds, showed slightly better survival, but only during the first growing period. The small advantages obtained from large seed mass in seedling development do not seem to justify the increased operational costs derived from seed mass selection for each family.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Differences in growth and mineral nutrition of seedlings produced from ten white spruce seed orchards

To meet the needs for improved spruce seeds in the province of Quebec, Canada, 17 first-generation white spruce seed orchards (SO) were established. These SOs are located in different bioclimatic domains and contain seed trees originating from geographically and genetically distinct sources. To evaluate the influence of SO on seedling growth and morphology, seedlings produced with seeds originating from the ten most commonly used first-generation white spruce SO in Quebec were raised under similar nursery conditions. Tissue nutrient concentrations of seedlings evolved similarly among seed orchards during the second growing season. At the end of the growing season, only shoot phosphorus concentrations were significantly different. When modeled with a logistic function, there was a significant difference between height and diameter growth curve parameters of seedlings from distinct SO during the second growing season. These differences led to significant differences in the height and shoot dry mass of the seedlings at the end of their second growing season, but not in their diameter or root dry mass. The ten SOs were clustered in two groups according to the above-ground characteristics of their progeny. This limited amount of morphological diversity suggests that expanding the size of the present seed zones may be an appropriate course of action for white spruce seed production in Quebec.     

不同种苗类型白及物候及产量研究

对球茎、种子苗两种不同类型白及苗种植后的物候进行了定株观测,并调查了两种类型种苗在不同种植密度下的产量.结果表明:两种繁殖类型的白及植株出芽、展叶期基本一致,球茎和种子苗植株出芽期、展叶期、开花期、果期持续时间差异不大,而黄枯期差异较大.不同种苗类型和不同种植密度对白及产量有显著影响.采用球茎种植的白及产量显著高于种子...     

Seed spacing and seedling biomass: Effect on root growth potential of loblolly pine (Pinus taeda)

Results from three studies conducted in bare-root nurseries indicate a positive linear relationship between seed spacing and root growth potential of Pinus taeda L. seedlings. However, root growth potential was also correlated with several morphological variables, including seedling weight, root collar diameter, root weight, root volume, foliage weight and stem weight. Because seedlings grown at wider spacings were larger in diameter and biomass, covariate analyses (using either root collar diameter or foliage ovendry weight) were also conducted. These analyses indicate that differences in root growth potential between seed spacings can be accounted for by differences in seedling size.     

Growth variability in a Senegalese provenance of Acacia nilotica ssp. tomentosa

Growth variability and effect of seed size on growth of seedlings of Acacia nilotica ssp. tomentosa of a Senegalese provenance were studied in a greenhouse experiment. Seedlings were raised from a sample of 52 seeds with a seed weight range of 0.070 g to 0.258 g; and a range of growth variables were measured on seedlings harvested 11 weeks after planting. Based on the sample mean and variance, the sample size required to estimate the parameter (mean) of the growth variables was determined. Seedlings showed a large variability in growth. There were five-fold and three-fold differences between seedlings in leaf area and total dry weight, respectively. Seed weight has little effect on seedling growth. The number of replications required to estimate a parameter mean of the different growth variables, within ±20% margin of error at P = 0.05, ranged from nine to 24. The observed growth variability was indicated to be an important biological variable which could be used to improve growth and yield in A. nilotica.This revised version was published online in November 2005 with corrections to the Cover Date.