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以毛金竹鞭段为试验材料,研究竹鞭年龄、竹鞭长度、育苗时间、育苗方式以及施肥等因素对鞭段成活率、竹苗高度、鞭段侧芽萌发率等的影响,以期为毛金竹鞭段育苗提供技术支撑。结果表明：随鞭段年龄增加,鞭段成活率和侧芽萌发率逐渐降低;随鞭段长度增加,鞭段成活率呈升高的变化趋势,侧芽萌发率则表现为先降低后升高的变化趋势;12月下旬鞭段育苗效果总体好于3月下旬和4月中旬。12月下旬育苗,育苗至出笋历时87 d,鞭段成活率和侧芽萌发率最高,分别为80.30%和20.79%;3月下旬育苗,育苗至出笋历时35 d,鞭段成活率和侧芽萌发率分别为51.74%和9.45%;4月中旬育苗,育苗至出笋历时20 d,鞭段成活率和侧芽萌发率分别为58.58%和9.56%。竹苗高度和育苗系数也表现为12月下旬育苗显著高于3月下旬和4月中旬育苗。采用施肥处理的鞭段进行育苗,鞭段成活率和竹苗高度明显优于未施肥处理的鞭段。在毛金竹鞭段育苗初期,新生竹苗表现出混生竹的生长行为。 相似文献
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云南高氏甜龙竹苗木质量分级及造林效果 总被引：1，自引：1，他引：0
为保障高氏甜龙竹（商品名）苗木质量,提高造林效果,在昆明市嵩明县、富民县,保山市昌宁县,玉溪市元江县开展了播种育苗和扦插育苗试验,以苗高、地径为分级指标研究了高氏甜龙竹1年生苗的分级标准。结果显示,不同地区苗木的分级标准具有一定差异,其中富民县和元江县对Ⅰ级苗的要求较高,富民县Ⅰ级播种苗要求苗高≥8.31 m、地径≥4.63 cm,元江县Ⅰ级扦插苗要求苗高≥6.55 m、地径≥3.67 cm。高氏甜龙竹不同育苗方式,其苗木生长状况存在差异,表现为播种苗的各项生长指标均好于扦插苗,特别是根系的生长状况和每丛株数,播种苗的平均根系数量、根系总质量、每丛株数分别是扦插苗的7.07倍、7.13倍和6.69倍,表明播种苗以后的生长潜力更大。不同等级的高氏甜龙竹苗木的造林效果,无论是播种苗还是扦插苗,Ⅰ级苗的造林成活率均达到100%,Ⅱ级苗的造林成活率也可达到95%以上,Ⅲ级苗的造林成活率均低于82%。 相似文献
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Seasonality in rooting of cuttings and its relationship with some environmental conditions and growth parameters of Prosopis chilensis (Mol. Stunz) were studied. It was observed that rooting could be induced in cuttings taken from field collections only during the dry season, the period corresponding to the highest vegetative growth and reproductive activity (September to March); however, percentages did not exceed 15%. The rooting response does not occur during the dormant period (May to September). When using cuttings from clonal material growing in the glasshouse, rootings exceeding 80% were obtained in liquid aerated media.
In-vitro micropropagation was assessed in P. chilensis using nodal and apical segments collected both from the field and from clonal material and plantlets grown from seed in the glasshouse. Juvenile material gave an 80% regeneration rate of complete plants in Murashige-Skoog medium fortified with 5 mg naphtaleneacetic acid 1−1 and 10 mg cysteine 1−1. In this same medium, the regenerative response of segments obtained from rooted cuttings was 60%. The material collected from the field showed no rooting responses. 相似文献
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Gurbachan Singh 《Forest Ecology and Management》1996,80(1-3):267-278
Effects of three methods of site preparation, i.e. trench (30 cm deep and 30 cm wide dug across the plots), pit (30 cm × 30 cm × 30 cm) and augerhole (15cm diameter and 90 cm deep) on raising Prosopis juliflora plantations on a highly alkali soil (pH2 10.3) were studied in a field experiment at Gudha Experimental Farm of the Central Soil Salinity Research Institute, Karnal. A uniform dose of gypsum of 3 kg per plant was mixed with the excavated soil before trenches/pits/augerholes were refilled and Prosopis planted. The study indicated that mean plant height and girth growth, recorded at 2 year intervals from planting up to 8 years, were greatest with the augerhole method. Similarly, the air dried shoot and root biomass accumulated by Prosopis in 6 years was maximum in augerhole planting. In trench and pit planting, most of the roots were confined to surface layers (0–60 cm), whereas in augerhole the roots were able to pierce the hard CaCO3 layer (caliche bed) and were nearly 2.5 m deep 2 years after planting. Differential site preparation techniques showed little effect on N, P, K, Ca, Mg, S and Na concentrations in plant parts (leaf, branch and stem) of Prosopis both at 2 and 6 years after planting. Total removal of N, P, K, Ca, Mg and S through Prosopis parts at 2 and 6 years after planting was maximum in auger planting and minimum in trench planting. The augerhole was also superior to other techniques in pod production, litter yield and nutrient additions to the site. However, litter quality remained unaffected owing to planting techniques. In general, there was marked decrease in pH and electrical conductivity and appreciable improvement in organic carbon and available N status of the experimental soil owing to Prosopis growth, but effect of different site preparation methods was not significant. This study showed that site preparation for planting Prosopis in high pH soils in the vertically downward direction is more important than reclamation of surface soil in the horizontal direction. 相似文献
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P. J. C. Harris N. M. Pasiecznik S. J. Smith J. M. Billington L. Ramírez 《Forest Ecology and Management》2003,180(1-3):153-164
Two species of Prosopis, Prosopis juliflora and Prosopis pallida, native to Central America and northern South America, have been widely introduced and are now found throughout the world’s hot arid and semi-arid zones. However, these species are frequently misidentified, especially where introduced, hampering genetic improvement and effective management. Samples from trees previously identified as either P. juliflora or P. pallida were divided into two groups by multivariate analysis using selected foliar characters. One group contained known tetraploids and the other contained known diploids. It was concluded that the tetraploid and diploid groups correspond to P. juliflora and P. pallida, respectively. Triploid individuals were also identified, the first report of these in the genus Prosopis. A dichotomous key was developed to differentiate the species, using number of interfoliar glands per rachis, number of leaflet pairs per pinna and leaflet length. P. juliflora and P. pallida grown from seed collected within their respective native ranges were correctly identified using the key. Where introduced, samples from Burkina Faso, Jordan and India were confirmed as P. juliflora, but those from Brazil, Cape Verde and Senegal were identified as P. pallida, rather than P. juliflora, the species assumed to be naturalized in these countries. The correct identification of these two species will facilitate the genetic improvement and management of P. juliflora and P. pallida. There is a strong case for basing future selection and genetic improvement programs on P. pallida rather than P. juliflora. Further collection and evaluation of P. pallida is therefore required, together with conservation programs in the native range. 相似文献
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The objective was to study the influence of vegetation cover, humus depth, microrelief and distance to seed tree edge on natural regeneration of Norway spruce (Picea abies (L.) Karst.) in five small clear-cuts on bilberry woodland in southeastern Norway. The impact of the vegetation was considered at tree different scales: at the growing point, in the nearest square decimetre around the seedlings and at a 1 m2 scale. Most of the regeneration (95%) developed in 1996, after a rich seed year in 1995. The microhabitat was of crucial importance to seedling establishment. Litter, Sphagnum spp. and Polytrichum commune were good substrates for establishment, while areas dominated by Deschampsia flexuosa, Dicranum spp. and Pleurozium schreberi had very few seedlings. Seedling survival after five growing seasons was slightly better in litter than in Sphagnum and other mosses, but the differences were not statistically significant. Increasing humus depth had a positive influence on regeneration, probably due to shallow soils at the sites. Even though depressions covered only 4.9% of the ground, 24.1% of the seedlings occurred here. Survival was, however, lower in depressions than in the other microrelief classes. Distance to the seed tree edge had a significant influence on establishment, with more seedlings establishing close to the edge. 相似文献
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J. Doland Nichols Michael R. Wagner Victor K. Agyeman Paul Bosu Joseph R. Cobbinah 《Forest Ecology and Management》1998,110(1-3):353-362
Milicia excelsa and M. regia are important timber species in moist tropical areas of Africa. They have not been successfully grown largely because of attacks by gall-forming psyllids in the genus Phytolyma. Our objectives were to evaluate the growth of planted Milicia seedlings and incidence of psyllid attack in small (4.2 m2), medium (18.5 m2) and large (>500 m2) artificial gaps in the Bobiri Forest Reserve in the Moist Semi-Deciduous Forest of Ghana. After 13 months, height and diameter growth of Milicia seedlings were significantly greater in the medium and large gaps than in the small gaps. Insect attacks occurred first and most severely in the large gaps, but spread to gaps of all sizes between the 11th and 13th months after planting. While gap size significantly affected the susceptibility of seedlings to psyllid attack, it is not the only factor important in determining susceptibility of Milicia excelsa under field conditions. We conclude that gap sizes in the range of 10–50 m2, where irradiances are from 30–60% of full sunlight, in forests similar to those at the study site, seem to be most suitable for regeneration of Milicia. 相似文献
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We have experimentally investigated the impact of biotic factors, acting at the seed and seedling stages, on a Quercus pyrenaica forest in the Sierra Nevada mountains (SE Spain). We monitored the natural establishment of the oak for 3 years in two forest plots and two shrubland plots, by counting seedlings and juveniles. In addition, we established several experiments in these plots to examine acorn and seedling survival, while also considering the microhabitat effect on survival probability. Dispersed acorns were quickly consumed by several species of predators, particularly wild boar (Sus scrofa) and woodmouse (Apodemus sylvaticus). Less than 4% of the experimental acorns survived to produce seedlings, even when they were buried 4 cm in soil, simulating caches. No effect of microhabitat was found on predation, and thus no safe site appears to exist for Q. pyrenaica acorns in the study area. Some 98% of the 1000 experimental seedlings were killed by herbivores, notably woodmice, wild boar, and domestic and wild ungulates. Seedling survival varied spatially, being significantly higher under shrubs (4%) than in any other microhabitat (less than 0.5%). Both acorn and seedling survival were much lower in the shrublands than in the forests. In shrubland plots, the main agent of seedling mortality was trampling by domestic ungulates foraging in herds. This study suggests that the regeneration of Q. pyrenaica forests in Mediterranean mountains can be limited by herbivores acting at several life-history stages. 相似文献
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Seasonal and substrate effects on first-year seedling establishment of major conifer species (Abies mariesii, Abies veitchii, Picea jezoensis var. hondoensis, and Tsuga diversifolia) were assessed in an old-growth subalpine forest in central Japan. Older seedlings (≥1 year) were more abundant on woody debris (WD), such as fallen logs, than on soil. It is known that this preferential seedling establishment on WD is determined by the first-year seedling establishment. The present results indicate that first-summer seedling survivorship clearly contributes to the creation of such seedling–substrate associations, because mortality during the first-summer was greater on soil than WD but that during the first-autumn/winter was not different. Although the standardized mortality rate of current-year seedlings on WD was not so different among the three seasons, that on soil significantly decreased in the winter; indicating that soil is not an unsuitable substrate for seedling survivorship during snow-covered winter. Thus, it can be concluded that biotic and abiotic factors enhancing seedling mortality on soil are most active during summer, and seedling–substrate associations seem to be determined mainly during the first-summer soon after seedling emergence. Furthermore, the first-year survivorship of P. jezoensis var. hondoensis, which has smaller-sized seeds/seedlings that are disadvantageous for early survival, decreased with progressing WD decay toward soil. This suggests that the properties of WD also affect current-year seedling survivorship, especially for species sensitive to substrate properties. In conclusion, initial survivorship affects seedling bank dynamics, and such early dynamics are greatly regulated by the highly heterogeneous substrate availability on forest floors. 相似文献
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For 3 years following a severe, November 1992 tornado, abundance and growth of tree regeneration in intact forest-floor and windthrow-pit microsites were studied in three mixed pine and hardwood stands in the Georgia Piedmont, USA. The research had two objectives: (1) determine if performance of tree regeneration differed between microsite types and between pre- and post-tornado cohorts on intact forest-floor microsites, and (2) determine if variation in light and soil water availability from the disturbance affected performance of eight species artificially seeded into intact forest-floor microsites. Near each of the 42 sample points (12–20 per site) spaced on 15 m grids, species and height of tree seedlings were recorded within a 1 m radius plot of intact forest floor and the nearest windthrow pit. Intact forest-floor microsites were dominated by two late-successional species, Acer rubrum (3.5 pre-tornado stems per m2 and 1.8 post-tornado stems per m2) and Ostrya virginiana (2.6 post-tornado stems per m2), while windthrow pits were dominated by an early successional species, Liriodendron tulipifera (1.7 stems per m2). Although seedling survival did not vary significantly among species or microsite types, first-year height of seedlings in intact forest-floor microsites (24 cm) was significantly greater than those in windthrow-pit microsites (19 cm). Second-year height growth of new seedlings of Cornus florida in intact forest-floor microsites (52 cm) significantly exceeded that of many other combinations of species and microsite type. Species artificially-seeded into intact forest-floor microsites in 1994 and 1995 varied considerably in emergence (<1–24%), survival (<1–16%), and height (5–15 cm), and those with the heaviest seed survived best. From 1994 to 1995, average gap fraction, an index of light availability, decreased 17% from 0.23 to 0.19. Soil water content in 1995 under gap fractions of greater than 0.3 (21%) averaged significantly less than under gap fractions of either 0.1–0.3 (24%) or less than 0.1 (26%). Significant positive correlations were detected for relationships of emergence and survival of several species to soil water content. Overall rankings of seedling performance between microsites (intact forest floor>windthrow pits), between cohorts (pre-tornado>post-tornado origin), and among species (mid- to late->early-successional species) indicate that advanced regeneration and new seedlings of A. rubrum, O. virginiana, and C. florida will be long-term dominants of the understory because of their high abundance, initial growth responses, and shade tolerance. 相似文献
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Interactions between forest canopy characteristics and plants in the forest understory are important determinants of forest community structure and dynamics. In the highlands of southwestern, China the dwarf bamboo Bashania fangiana Yi is an understory dominant beneath a mixed canopy of the evergreen Abies faxoniana (Rheder & Wilson) and the deciduous Betula utilis (D. Don). The goal of this study was to better understand the role of bamboo dominance, canopy characteristics, and periodic bamboo dieback on forest development. To achieve this goal, we measured tree seedling, tree saplings, and trees, forest canopy characteristics, and bamboo cover in permanent forest (n = 4) and gap plots (n = 31) in a mixed A. faxoniana and B. utilis forest in Sichuan, China. Dwarf bamboos died off in 1983 in the gap plots, and in three of the four forest plots. Forest development was assessed for the period 1984–1996. The seedling bank in forest and gap plots increased after bamboo die-off. A. faxoniana seedlings increased more than B. utilis in forest plots; the opposite pattern characterized gap plots. The proportion of seedlings on raised micro-sites on the forest floor also changed and new seedling were more abundant on the forest floor. By 1996, bamboo seedling cover and biomass had recovered to ca. 45% or their pre-flowering values. Rates of bamboo seedling recovery were faster beneath canopy gaps and deciduous trees than beneath forest or evergreen trees. Tree mortality exceeded recruitment in plots with dense bamboo; the opposite pattern was found in the plot with little bamboo. The mortality rate for B. utilis trees (2.4% year−1) was higher than that for A. faxoniana (0.8% year−1) and forests with dense bamboos became more open over the census period. Tree mortality was size-dependent and intermediate sized trees had the lowest rates of mortality. Stand basal area increased mainly due to greater basal area gain than loss for A. faxoniana. Interactions between tree species life history, canopy type, and bamboo life-cycles create heterogeneous conditions that influence tree and bamboo regeneration and contribute to the coexistence of A. faxoniana and B. utilis in old-growth forests in southwestern China. 相似文献
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Bruchidius andrewesi Pic. has been recorded as a serious pest of pods and seeds of Acacia tortilis in the Thar desert of India. Pest infestation on developing pods and its relationship with morphological traits is reported. Pod infestation varied from 5 to 19% with 5–29% infestation of seeds. Infestation of pods is directly related to infestation of seed (r = 0.72**), and both pod and seed infestation are also directly correlated with loss in seed biomass (r = 0.79** and R = 0.88**). The infestation of pods starts in November and increases steady until harvest. Seeds kept in the laboratory for further studies were found to be 100% infested with B. andrewesi, as the insect multiplied faster under these conditions. The heavy infestation is damaging not only to A. tortilis but also to other leguminous trees of the desert. Bruchidius andrewesi has also been found on pods and seeds of Prosopis cineraria, an important indigenous tree of the region. 相似文献
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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. 相似文献
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The survival of bare-root and container-grown loblolly pine (Pinus taeda L.) seedlings exceeded 90% when outplanted in March at two sites in Lee County, Alabama. At both sites, soil moisture and seedling survival were greater in March than in May. A March herbicide application reduced weed biomass by 75–80% at both sites. At the moist site, herbicide application did not affect survival. However, at the drier site, a reduction in weed biomass increased both the percent soil moisture and the survival of May-planted bare-root seedlings. When soil moisture at planting time was less than 13% on a dry weight basis container-grown seedlings survived better than bare-root seedlings. At both sites, reduced weed competition resulted in greater seedling heights and diameters.Alabama Experiment Station Journal Series No. 9-85802. 相似文献
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大娄山区金佛山方竹种子营养成分与播种育苗 总被引：1，自引：1，他引：0
调查了大娄山区金佛山方竹的开花结实历程,并采集8个不同地点的金佛山方竹种子分析其营养成分,同时进行种子育苗试验。结果显示：1）大娄山区金佛山方竹在11月前后产生花枝,翌年2月初至3月中旬开花,4月中旬至5月初种子成熟;2）鲜种子千粒质量为230.9~342.5 g,种子含有丰富的蛋白质、脂肪、多糖、碳水化合物、多种氨基酸和矿质元素;3）种子成熟后不耐储藏,40 d后便失去发芽力,种子育苗应随采随播;4）人工异地播种其苗木质量优于原生林落种形成的苗木质量。 相似文献
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为提高主要栽培珍贵树种米老排(Mytilaria laosensis)组培苗的移植成活率,以选育的优良无性系组培生根苗为材料,研究炼苗方式、基质、苗木规格、植后施肥及移植季节等对移植成活率和苗木生长发育的影响.结果表明:松盖炼苗3 d,出瓶苗高度大于2 cm,植后3 d喷施1 MS大量元素营养液是较好的处理,在大棚条件下移植,不带黄心土的轻基质和河沙都是适合基质,移植成活率90%以上,在大田条件下移植,以黄心土:泥炭土=1:1或黄心土:蛭石=1:1为基质移植成活率较高.移植季节以4月成活率最高,9月、10月其次,考虑到我国南方地区最佳造林季节为3—5月,为减少苗圃管理成本,米老排组培苗生产安排在9—10月出瓶移植是比较合理的选择. 相似文献