云南龙竹实生苗质量分级探讨

为评价云南龙竹实生苗质量,以其半年生实生苗为研究对象,以地径、苗高、每丛株数为苗木质量分级指标,采用K均值聚类法及标准差法确定苗木质量等级。结果表明：云南龙竹实生苗苗高、地径与其他生长指标之间均呈极显著正相关(P<0.01),以苗高、地径和每丛株数作为苗木质量等级划分的依据是可行的。经综合评定,确定云南龙竹半年生实生苗质量分级标准为：Ⅰ级苗高度≥37 cm、地径≥3 mm、每丛株数≥4;Ⅱ级苗27≤苗高<37 cm、2≤地径<3 mm、3≤每丛株数<4株;Ⅲ级苗16≤苗高<27 cm、1≤地径<2 mm、2≤每丛株数<3株。研究结果可为云南龙竹苗木等级进一步划分和良种选育提供科学依据。     

台湾桤木播种育苗苗木产量与质量关系研究

对正常培育情况下的台湾桤木播种育苗苗木地径生长、苗高生长、株行距（单位面积株数）等情况进行了调查。在相关研究的基础上，分别建立了单位面积苗木株数与苗高生长、地径生长的数学模型，研究结果表明：要使苗木平均高度达80cm以上、平均地径0．8cm以上，则保留苗木株数应小于33株/m^2，即保留苗木（苗木实际占有面积按65％计算）株数应小于21万株/hm^2。     

不同留苗株数对刺槐苗地径等级的影响

在辽西半干旱地区,以苗圃地播种获得的刺槐1年生幼苗为对象,研究了刺槐实生苗不同留苗密度对苗木质量的影响。结果表明:留苗密度在12万~20万株·hm-2范围内,产出的Ⅰ级苗木的数量最多,达到6万~9万株·hm-2,且Ⅰ和Ⅱ级苗占总留苗株数的百分率达90%以上;留苗密度12株·hm-2,Ⅰ和Ⅱ级苗占总留苗株数的百分率能够达90%以上,但产出的Ⅰ级苗木的数量减少;留苗密度20株·hm-2,Ⅰ和Ⅱ级苗占总留苗株数的百分率低于90%,且产出的Ⅰ级苗木的数量减少。     

不同立地条件香椿人工林木材材质的比较

通过对不同立地条件下香椿人工林木材物理力学性质的测定和比较分析表明:香椿人工林木材密度和干缩性随着立地级的提高而减小;木材顺纹抗压强度、抗弯强度和硬度:Ⅰ级地<Ⅱ级地<Ⅲ级地,抗弯弹性模量、抗劈力、冲击韧性:Ⅱ级地>Ⅰ级地>Ⅲ级地,顺纹抗剪强度:Ⅱ级地>Ⅲ级地>Ⅰ级地。差异显著性t检验表明:香椿人工林木材密度Ⅰ级地、Ⅱ级地、Ⅲ级地间差异不显著。香椿人工林木材干缩性和力学性质指标Ⅰ级、Ⅱ级、Ⅲ级地3者间有的指标差异极显著,有的指标差异显著,大部分指标差异不显著。     

落桦混交林幼龄期Ⅰ级木分布规律研究

利用３６块落叶松一样树混交林标准地调查资料，研究其幼龄期林分Ⅰ级木单位面积株数与林分密度之间的关系，结果表明：Ⅰ级木的株数并非随密度的增加而直线递增，而是趋向“二阶常数”分布，且在同一年龄阶段，在较低的密度范围（２３２５～４８００株／ｈｍ２）或较高的密度范围（４８０１～６７５０株／ｈｍ２）．Ⅰ级木的株数变动幅度不太大。     

红松 云杉 落叶松出苗率及保苗率的研究

黑龙江省森工系统多年来一直采用公式ｘ＝１０ｐｎｃ／ＥＫ计算播种量，但在实际工作中，发现在对出苗率、保苗率以及保苗株数进行计算时，存在一定的误差，而现行的《黑龙江省林区育苗技术标准》中又没有具体明确的规定。因此，本文通过理论推算和实际调查，对此问题做了进一步的探讨。１　理论推算出苗率是指某新播树种，苗木出齐后的单位面积出苗株数与单位面积播种的有效种子粒数的百分比。保苗率是指某新播树种，单位面积保苗株数与单位面积出苗株数百分比。对于任何一个树种，在给定播种系数Ｃ和单位面积保苗株数Ｎ以后，那么播种的有效种子粒数即为ＮＣ（Ｎ在播种量的计算公式中代表设计密度，即苗木等级表中单位面积的保留株数）。依据播种系数、出苗率８０％、保苗率６０％进行理论计算（见表１），并从正方向和逆方向两方面加以分析。从正方向看，如果按规程规定播种系数２－５，设计密度按苗木等级表中保苗株数上限９００株／ｍ２（兴安落叶松），根据出苗率８０％和保苗率６０％计算所得保苗株数为１０８０株／ｍ２，超出苗木等级表规定上限１８０株／ｍ２，超２０－２％，这说明在计算过程中出苗率、保苗率过高。云杉亦如此，其计算保留株数超过苗木等级表规定上限１７００株／ｍ２，超６８...     

乌桕富根苗及育苗密度研究

对1 a生乌桕苗木开展了GGR6促根处理及苗木培育密度试验。结果表明:GGR6处理能显著增加1 a生苗木Ⅰ级侧根的数量,形成乌桕富根苗;随着单位面积苗木株数的增加,苗木的苗高生长增加但地径生长减小。根据试验结果并结合生产实践,乌桕合适的育苗密度为40株·m~(-2);因此,适宜的GGR6处理浓度和适当的育苗密度是培育优质乌桕苗的关键。     

舟山新木姜子苗木分级及不同密度试验

以苗高和地径作为苗木分级的质量指标,对舟山新木姜子一、二年生苗木进行逐步聚类分级,得出一年生苗木分级标准为:Ⅰ级苗苗高≥19.7 cm,地径≥0.38 cm;19.7 cm>Ⅱ级苗苗高≥13.8 cm,0.38 cm>地径≥0.30cm;Ⅲ级苗苗高<13.8 cm,地径<0.30 cm.二年生苗木:Ⅰ级苗苗高≥49.1 cm,地径≥0.59 cm;49.1 cm>Ⅱ级苗苗高Ⅰ≥29.5 cm,0.59 cm>地径≥0.38 cm;Ⅲ级苗茁高<29.5 cm,地径<0.38 cm.应用分级标准对3种育苗密度的苗木进行分级.并通过不同密度与苗高、地径的方差分析,结果表明,培育一年生舟山新木姜子苗木最适密度为300株/m2,二年生苗木的最适密度为200株/m2.     

银杏芽苗移栽技术初探

采用小拱棚催出的银杏露白种子进行了继续催芽后移栽和直播大田育苗的对比试验。结果表明：继续催芽后移栽培育的苗木，其苗高、地径生长量分别比直播大田法提高８％和４％，Ⅰ、Ⅱ级苗株数前者比后者增加１０９００株／ｈｍ２。     

不同遮荫方式对光皮桦出苗量的影响

在福建省上杭县南阳苗圃开展的不同遮荫方式对光皮桦育苗出苗量的影响试验表明：遮荫是光皮桦育苗的一个关键措施，不同的遮荫方式对光皮桦育苗出苗量的影响差异极显著，采用通光度50％的遮荫网遮荫出苗量最高，平均达131株／m^2，且苗木质量好，Ⅰ级苗率达86%。     

Influence of water stress on the physiology and growth of red spruce seedlings

Two-year-old, container-grown red spruce (Picea rubens Sarg.) seedlings from a New Hampshire seed source were exposed to 10 or 11 drying cycles in which the seedlings were not watered until their midday (1400 h) xylem water potentials averaged -1.57 MPa. Control seedlings were kept well watered to maintain midday water potentials of about -0.73 MPa. After the final drying cycle, the water-stressed seedlings were rehydrated and osmotic potentials were determined by pressure-volume analysis. Gas exchange at ambient CO(2) concentration (338 ppm) and at an elevated CO(2) concentration (838 ppm) was measured on both groups of plants as they slowly dried down. No osmotic adjustment or photosynthetic acclimation occurred as a result of the water-stress treatment and both groups of seedlings maintained photosynthesis to water potentials as low as -3.0 MPa. Twenty-four hours after rehydration, the water-stressed seedlings had photosynthetic rates as high as the control seedlings. Estimated stomatal limitation to photosynthesis was approximately 30% down to water potentials of -1.4 MPa, but increased steadily as water potentials decreased further. At ambient CO(2) concentrations (338 ppm) and water potentials averaging -2.45 MPa, photosynthetic rates of water-stressed seedlings were 15% those of well-watered seedlings, whereas when the same water-stressed seedlings were measured in the presence of an elevated concentration of CO(2) (838 ppm) their photosynthetic rates were 73% those of well-watered seedlings measured at an ambient CO(2) concentration (338 ppm).     

Effect of CCC on the morphology and growth potential of containerised silver birch seedlings

The objective of the experiment described here was to assess the effect of the synthetic growth regulator CCC on the quality of containerised silver birch seedlings. The time course of stem elongation during the growing season, the morphology and size of the seedlings at the end of the growing season, and the growth potential after winter storage were measured and the following results obtained: (1) Stem height, root-collar diameter and total dry weight of the seedlings were decreased by CCC. (2) Stem-height:root-collar-diameter ratio was slightly decreased and root weight ratio was increased by CCC. (3) Stem flexibility was not significantly affected by CCC, although it was significantly correlated with total plant dry weight and with the stem-height:root-collar-diameter ratio. (4) Root-growth potential was decreased at high doses of CCC while shoot growth potential was not affected.     

Effect of CCC and daminozide on growth of silver birch container seedlings during three years after spraying

Applications of growth retardants, daminozide and CCC (chlormequatchloride), were studied in order to determine their effects on morphology and post-planting growth of silver birch (Betula pendula Roth) container seedlings. Daminozide was sprayed once (on 28 June at concentrations of 1.0 – 6.0 g l^–1) and CCC was sprayed twice (on 29 June and 27 July at concentrations of 0.5–3.0 gl^–1). Height growth, morphology of seedlings at the end of the growing season, the shoot and root growth potential the following spring and field performance during the following seasons were measured. During the first summer in the nursery, both daminozide and CCC retarded height growth,but daminozide was more effective. The effects of compounds on stem diameter during the summer of application were small. Neither of the compounds affected the field performance of seedlings. The most suitable applications for retardation of height growth, without negative effects on other morphological variables, were 4 g l^–1 (32 mg per seedling) for daminozide and 2 g l^–1 (16 mg per seedling), sprayed in two applications, for CCC.     

Early developmental responses of mountain birch (Betula pubescens subsp. czerepanovii) seedlings to different concentrations of phosphorus

Phenolic compounds, identified by high performance liquid chromatography (HPLC), and growth were investigated in the first true leaves, cotyledons, stems and roots of 2.5-week-old seedlings of mountain birch (Betula pubescens subsp. czerepanovii (Orlova) H?metahti) grown with 1.5, 15 and 50 ppm phosphorus (P). Phenolic compounds in seeds and unfertilized 6-day-old seedlings were also studied. Seeds contained few phenolics, but had an abundance of condensed tannins. There were fewer HPLC phenolic compounds in 6-day-old seedlings than in 2.5-week-old seedlings. In 2.5-week-old seedlings, growth of the first true leaves, but not of other plant parts, was affected by P regime. In the first true leaves and stems, the concentration of condensed tannins was significantly affected by P, being higher at 1.5 ppm than at higher concentrations. The concentration of total HPLC phenolics was significantly affected by P only in stems.     

植物生长延缓剂对越冬期辣韭矢竹组培苗生长的影响

植物生长延缓剂能够抑制植物细胞生长,使植株长得粗壮,根系发达,从而增强植物的抗逆性。试验研究了不同浓度的植物生长延缓剂矮壮素(CCC)和多效唑(PP₃₃₃)对越冬期辣韭矢竹组培苗生长的影响。结果表明:经CCC和PP₃₃₃处理后的苗木,植株高生长明显降低,而分枝率和分蘖率显著增加;对植株叶绿素荧光参数的影响表现为,PSⅡ最大光化学效率(Fv/Fm)、非光化学猝灭系数(NPQ)和电子传递速率(ETR)均显著上升,光化学量子效率(ΦPSⅡ)和光化学猝灭系数(qP)均显著下降,表明竹苗接受和传递光电子的能力增强,光合潜力上升,光机构得到保护,受低温伤害减轻,植株抗寒性增强。比较不同浓度CCC和PP₃₃₃的处理效果显示,800 mg/L的PP₃₃₃和3 000 mg/L的CCC处理的植株均有较好的抗寒能力。综合来看,3 000 mg/L的CCC对辣韭矢竹苗在寒冷条件下的保护最全面。     

Rock phosphate and vesicular-arbuscular mycorrhiza effects on growth and nutrient uptake of Faidherbia albida (Del.) seedlings in an alkaline sandy soil

Response of Faidherbia albida (Del.) to five levels of Kodjari rock phosphate (KRP) application (0, 310, 620, 1240 and 2480 ppm P, equivalent to 0, 775, 1550, 3100 and 6200 kg P/ha) and vesicular-arbuscular mycorrhizal fungi (VAMF) Glomus manihotis Howeler, Sieverding & Schenck or Glomus aggregatum Schenck & Smith emend. Koske was evaluated in an alkaline sandy soil. The F. albida seedlings grew poorly without mycorrhizal colonization and without KRP applications. For non-VAM Faidherbia, the maximum growth response and both P and N uptake in shoots was achieved with the 620 ppm P. However, even without KRP application, VAM plants achieved better results in terms of biomass. VAM plants with G. manihotis and G. aggregatum improved plant growth and increased nutrient contents at any KRP application rate. Although mycorrhizal colonization was comparable at all levels of KRP application, the impact of nutrient content of the shoot varied. Finally, VAM plants did not accumulate more biomass than non-VAM plants at 620 ppm P and above. Growth response and mycorrhizal dependency decreased as KRP applied levels increased. These results suggest that VAM Faidherbia seedlings take up more P from soil and KRP than non-VAM.     

稀土对泡桐苗木生长效应的研究

农业上应用稀土已取得显著效益。为准确地肯定稀土对林业苗木的增产效用,并摸索关键技术,1987年至1989年,在温室和田间进行泡桐实生苗水培和埋根苗应用试验。水培试验部分地采用了植物稳态营养研究的理论和方法。     

Effects of elevated CO(2) and light availability on the photosynthetic light response of trees of contrasting shade tolerance

Photosynthetic light response curves (A/PPFD), leaf N concentration and content, and relative leaf absorbance (alpha(r)) were measured in 1-year-old seedlings of shade-intolerant Betula papyrifera Marsh., moderately shade-tolerant Quercus rubra L. and shade-tolerant Acer rubrum L. Seedlings were grown in full sun or 26% of full sun (shade) and in ambient (350 ppm) or elevated (714 ppm) CO(2) for 80 days. In the shade treatments, 80% of the daily PPFD on cloud-free days was provided by two 30-min sun patches at midday. In Q. rubra and A. rubrum, leaf N concentration and alpha(r) were significantly higher in seedlings in the shade treatments than in the sun treatments, and leaf N concentration was lower in seedlings in the ambient CO(2) treatments than in the elevated CO(2) treatments. Changes in alpha(r) and leaf N content suggest that reapportionment of leaf N into light harvesting machinery in response to shade and elevated CO(2) tended to increase with increasing shade tolerance of the plant. Shifts induced by elevated CO(2) in the A/PPFD relationship in sun plants were largest in B. papyrifera and least in A. rubrum: the reverse was true for shade plants. Elevated CO(2) resulted in increased light-saturated A in every species x light treatment combination, except in shaded B. papyrifera. The light compensation point (Gamma) decreased in response to shade in all species, and in response to elevated CO(2) in A. rubrum and Q. rubra. Acer rubrum had the greatest increases in apparent quantum yield (phi) in response to shade and elevated CO(2). To illustrate the effects of shifts in A, Gamma and phi on daily C gain, daily integrated C balance was calculated for individual sun and shade leaves. Ignoring possible stomatal effects, estimated daily (24 h) leaf C balance was 218 to 442% higher in the elevated CO(2) treatments than in the ambient CO(2) treatments in both sun and shade seedlings of Q. rubra and A. rubrum. These results suggest that the ability of species to acclimate photosynthetically to elevated CO(2) may, in part, be related to their ability to adapt to low irradiance. Such a relationship has implications for altered C balance and nitrogen use efficiency of understory seedlings.     

Acceleration of Early Growth of Seedlings and Rooted Cuttings of Quercus robur L.

The normal delays in the production of useful planting materialin tree species such as Quercus robur from both seedlings andcuttings can be overcome by growing the plants at relativelyhigh temperature and in continuous light. Top growth could befurther accelerated by application of gibberellic acid (GA3)as foliar spray. There were, however, distinct differences inresponse between seedlings (with a high root: top dry matterratio, 4:1), and freshly rooted cuttings. The latter evincedonly onefifth the seedling response, but when cuttings attainedsimilar root:top ratios, their response reached that of seedlings. GA3 treatment accelerated top growth at the expense of rootgrowth, but a root dip for 4h in 100 ppm indole-3yl-butyricacid (IBA) given to 4-month-old cuttings restored root growthto normal even with GA3 treatment. During rooting, cutting commonlybecame dormant but this was prevented by foliar GA3 sprays.Growth was further and substantially improved by inclusion ofcytokinin in such sprays (benzylandenine purine, BAP). Furtherimprovements of growth were obtained by 5% sucrose suppliedto the foliage. In field experiments, assessing ‘establishment’of seedlings and cuttings, the latter established well but after550 days still had not attained the same root:shoot ratio asseedlings. GA3 (50 ppm) again greatly promoted shoot growth,while BAP increased branching and leaf number; when given togethermaximum leaf numbers and shoot dry weight were obtained, yetroot growth remained normal. Further addition of IBA raisedshoot growth still further, but other characters measured sufferedreductions. The potential use of these findings is discussed.     

生长调节剂在核桃上应用效果分析

2种生长调节剂在核桃上的应用效果显示:P333和CCC对核桃新枝生长具有显著的影响。不同的品系对2种生长调节剂的反应存在显著差异。在对新枝粗度的影响中,促进作用最强的是CCC200;在对新枝长度的影响中,抑制作用最强的是CCC100和CCC200。