The relationship between the needle age and the growth rate in Scots pine (Pinus sylvestris): a retrospective analysis by needle trace method (NTM)

Variation in annual radial and height increments (RI and HI, respectively) as well as the number of needles belonging to different needle sets of successive annual shoots, determined by the needle trace method (NTM), was studied retrospectively in Scots pine stands, one in southern Finland and two in Estonia. The connection between different needle sets and tree growth was studied by correlation and covariance analyses. The numbers of needles of the three youngest needle sets were positively correlated with growth, whereas the number of needles older than 3 years had no significant correlation. The covariance analysis emphasized the negative relationship of older needle sets with tree growth. It is generally concluded that the two or three youngest needle sets are important and all older needles minimally contribute to growth, possibly because of their small quantity. Older needles may remain on the tree if assimilation is impeded for some reason, e.g. due to premature loss in the two youngest needle sets. The trees having attached old needles grew less than those that had already totally lost these needle sets.     

林分径阶蓄积量与材种出材量测算的研究

研究了林分径阶蓄积量与材种出材量的估测模型,其基本原理是应用相对树高曲线法测定林分径阶蓄积量,应用一致性削度方程法计算径阶单木材种出材率;相对树高曲线法与一致性削度方程法是基于胸径和树高两个测树因子的二元立木材积测定系统,通过建立较完善的数学模型改进计算方法,提高估测效果.     

不同苜蓿品种对牛角花齿蓟马的耐害性研究

评价8个苜蓿品种在牛角花齿蓟马(Odontothrips loti Haliday)不同密度成虫为害后的抗性表现,并从株高、分枝数及产量损失率3个方面测定,以揭示各品种对蓟马的耐害性以及苜蓿抗蓟马研究的最适接虫量.结果表明:随着虫口密度的增大,各苜蓿品种植株的为害指数明显上升,M8和HA-3苜蓿均表现为抗牛角花齿蓟马,Ja苜蓿表现为高感蓟马,其他苜蓿品种处于中等水平;产量损失率M8、HA-3最低,Ja最高,在株高和分枝方面呈现相同规律;研究表明M8、HA-3苜蓿对牛角花齿蓟马的耐害性最高,Ja苜蓿的耐害性最差.     

Predicting seedling biomass of radiata pine from allometric variables

Allometric equations predict tree seedling biomass from non-destructively measured variables such as stem diameter (D), height (H) and seedling silhouette area (A), measured by digital imaging. This study investigates whether one general allometric equation can predict biomass of radiata pine (Pinus radiata D.Don) seedlings grown under three levels of photosynthetic photon flux density (PPFD). It also identifies which commonly used variables (A, D ² H or D ²) were the best for predicting seedling biomass under these conditions. Radiata pine seedlings were grown with constant daytime (12 h d⁻¹) PPFD = 500, 250 or 125 μmol m⁻² s⁻¹ for 11 weeks. Seedlings were randomly selected every 10 d for measurement. Analysis of covariance tested whether the relationship between seedling biomass and A, D ² H or D ² varied for each PPFD level. PPFD levels influenced the relationship between biomass and A, D ² H or D ². As a result, “full” allometric models which varied with PPFD levels were more accurate and precise at predicting biomass than “reduced” models which did not vary with PPFD level, although a “reduced” model using D ² also performed well.     

60Co-γ射线辐射鸡冠花种子对其发芽率及幼苗生长的影响

用不同剂量60Co蛳γ射线辐射鸡冠花种子,观测其对种子发芽率和幼苗生长的影响。结果表明:发芽率和辐射剂量呈正相关;根长、苗高和辐射剂量呈负相关。辐射可促进鸡冠花发芽,但抑制生长。     

红松优树子代幼树高生长速生性状与遗传测定

在红松自然分布区内对3个亚区、9个地点、108株优树的子代10年生幼树测定结果表明，高生长可作为优树表型遗传选择。亚区间和家系／地点／亚区间差异显著、极显著，北亚区带岭优树子代高生长表现最好；亚区、地点／亚区、家系／地点／亚区遗传力分别为0．836，0．537，0．365。     

树莓组培苗驯化技术研究

应用组织培养技术繁育树莓种苗可解决根蘖分株、埋土压条和扦插繁殖,出现生育周期长、苗木质量参差不齐、品种退化、繁殖速度慢等缺点。驯化成活率是组织培养技术能否应用到生产上的关键。高成活率可提高组培苗的利用率,降低生产成本。本试验研究树莓组培苗的生根方式、苗高度、根系长度、苗叶片数及遮光率对驯化成活率的影响。结果显示:双季2831根长为0~0.5 cm时将瓶苗移至驯化室开始驯化,长至组培苗株高2~3 cm,根系长度0.5 cm,2片叶时进行移栽;单季1132根长为0~1.0 cm时将瓶苗移至驯化室开始驯化,长至组培苗株高2~3 cm,根系长度0.5~1.0 cm,二三片叶时进行移栽,移栽后遮光率20%~30%。     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

应用曲线模型解析施肥对白桦苗期年高生长节律的影响

为了解析施肥对白桦苗期年高生长节律的影响,以30个白桦无性系1年生盆栽苗木为试验材料,利用前期筛选的施肥配方对其分别进行间隔7、14、21 d/次的施肥处理,以不施肥处理为对照。自5月1日至9月29日,每隔15~18 d进行1次苗高调查。针对调查的所有苗高数据进行方差分析和多重比较,利用方程分别对不同施肥处理下各无性系的苗高生长曲线模型进行拟合,Logistic根据曲线模型预测的速生期各参数变化规律,分析施肥促进白桦高生长的机制。结果表明:各施肥处理之间、各无性系之间均存在极显著差异(P<0.01),施肥处理与无性系之间的交互作用显著(P<0.05);各处理下白桦无性系苗高生长均符合"S"形曲线模型,各处理下及各无性系的Logistic方程拟合系数均高于0.97。由施肥与对照处理下苗高生长模型参数比较可知,施肥显著促进白桦高生长的机制是延长了速生期的生长时间,增加了速生点处生长速度,提高了速生期苗高的生长量及日生长量。3种处理中以处理1效果最好,其苗高实测值较对照提高了62.89%;各无性系对施肥的响应存在差异,有的无性系喜肥、有的耐瘠薄,而无性系W11、W5的适应性较强,在各种肥力条件下均生长较好。     

关帝山林区天然落叶松林单木生长过程模拟

通过野外试验、室内数据整理、计算机模拟等手段,研究不同立地条件下天然落叶松生长过程变化.结果表明：不同立地条件下天然落叶松胸径生长过程拟合选出的最优方程为Richards方程;落叶松胸径、树高前5 a生长缓慢,5 a后加速生长;落叶松材积在前10a生长缓慢,10 a后加速生长;前30 a落叶松胸径、树高、材积总生长量差别表现不明显,30 a后立地条件越好,生长量越大.