油茶高接换冠嫁接成活率影响试验

用长林系油茶4号、18号、21号、40号和55号5个优良新品种作接穗,对低产的普通油茶林进行高接换冠,开展砧木生长势、嫁接部位直径大小、嫁接高度、保留技数量和接穗新鲜程度5个因子对嫁接成活率的影响试验.结果表明,油茶砧木生长势越强嫁接成活率越高,砧木嫁接部位直径3～8cm嫁接成活率较高,接穗采集后越早嫁接成活率越高,砧木的嫁接高度、保留枝条数量对成活影响差异不显著.油茶砧木生长势强、嫁接部位直径3cm以上、接穗采集当天嫁接的成活率在90％以上.     

核桃苗砧嫁接大田育苗技术研究

建始县是湖北省核桃传统栽培区,核桃栽培历史悠久,由于嫁接技术不过关,制约核桃产业的发展。作者采用对等楔形和非对等楔形修取径粗1.0?左右核桃接穗进行核桃子苗砧不同方法嫁接试验,结果表明:成活率无显著差异;选用同批播种子苗在低山区进行不同时期核桃子苗嫁接试验,成活率以3月上旬气温达15℃左右时为最好,中旬次之。     

Age-related changes in foliar morphology and physiology in red spruce and their influence on declining photosynthetic rates and productivity with tree age

The contribution of changes in meristem behavior to age-related decline in forest productivity is poorly understood. We studied age-related trends in needle morphology and gas exchange in a population of red spruce (Picea rubens Sarg.) growing in a multi-cohort stand where trees ranged from first-year germinants to trees over 150 years old, as well as in grafted scions from these trees. In the field study, age-related trends in foliar morphology were determined in six cohorts ranging in age from 2 to 120 years, and differences in gas exchange characteristics were compared between 60- and 120-year age classes. In a common-rootstock study, scions from trees representing 20-, 60-, and 120-year cohorts were grafted onto juvenile rootstock and maintained for three growing seasons, after which morphological and physiological foliar attributes were evaluated. The field study revealed significant age-related trends in foliar morphology, including decreasing specific leaf area, and increasing needle width, projected area, and width/length ratio. Similar trends were apparent in foliage from the grafted scions. Both in situ foliage and shoots of grafted scions from the oldest cohort showed significantly lower photosynthetic rates than their counterparts from younger trees; however, differences in stomatal conductance and internal CO(2) concentrations were not significant. These results suggest that: (1) foliage of red spruce exhibits age-related trends in both morphology and physiology; (2) age-related decreases in photosynthetic rates contribute to declining productivity in old red spruce; (3) declines in photosynthetic rates result from nonstomatal limitations; and (4) age-related changes in morphology and physiology are inherent in meristems and persist for at least 3 years in scions grafted to juvenile rootstock.     

Factors influencing in vivo and in vitro micrografting of sandalwood (Santalum album L.): an endangered tree species

In vivo micrografting of Santalum album was achieved (50%) by grafting 4- to 5-cm-long scions, collected from a candidate plus tree (CPT) of 50–60 years of age, onto 90-day-old nursery-grown rootstock. Scion size, rootstock age, and scion collection season were found to influence graft success. Grafted plants were incubated under greenhouse conditions for 6–8 weeks during the graft union process. In vitro micrografts were achieved by placing 1- to 2-cm-long scions derived from nodal shoot segments (collected from CPT) onto the hypocotyl of 45-day-old in vitro rootstocks. Use of in vitro grown shoots as a source of scion gave better graft success (60%) than scions collected directly from field-grown trees. In vitro grafting was also influenced by scion size and rootstock age. Under favorable conditions, scions and hypocotyls unite to form complete plants that produced two to four leaves after 6–8 weeks. This is the first report on in vivo and in vitro micrografting of S. album having potential for production of disease-free clonal plants for conservation and improvement targets.     

Developing sustainable regeneration techniques for four African mahogany species: grafting methods for success and growth

Development of planting materials through vegetative propagation has been difficult in some timber species due to ontogenetic aging which slows down rooting of stem cuttings. Applying grafting techniques helped produce quality planting materials with unique characters, as these techniques influenced union establishment and successful growth of the grafted plants. This study assessed effects of different grafting techniques on establishment and early growth of four African mahogany species (Khaya ivorensis, K. anthotheca, K. grandifoliola and K. senegalensis) using 2-year old seedling rootstocks and scions from mature trees with desirable stem form. We assessed effects of three grafting methods (top-cleft, side grafting, and whip and tongue), and scion type on growth performance of the African mahogany species at 6 months after grafting. K. grandifoliola scion grafted onto K. grandifoliola rootstock recorded highest mean graft success (81.67%), number of leaves formed (11.6) and shoot height growth (7.47 cm) in the top-cleft method. The whip and tongue method was least successful among the three methods. Homografted plants had greatest influence on the grafting parameters for highest mean successes in K. grandifoliola/K. grandifoliola (81.67%), K. anthotheca/K. anthotheca (73.33%) and K. senegalensis/K. senegalensis (63.33%) except K. ivorensis scion type which occurred in the heterograft K. grandifoliola/K. ivorensis (76.67%). Highest performance of the top-cleft method is attributed to good contact between cambia of the grafted species and thus their easy union and growth. Grafting of the four African mahogany species is most successful using top-cleft grafting technique for sustainable production of improved cultivars for restoration and conservation.

     

麻栎嫁接育苗试验

采集湖南省森林植物园、安徽省滁州市南谯区红琊山林场25年生优良母树上的枝条作接穗,以1年生麻栎实生苗作砧木,选择插皮接、切接、腹接、T字形芽接和劈接等5种常规方法,进行麻栎嫁接试验,研究不同嫁接方法对麻栎嫁接成活率、苗高及地径的影响。结果表明:嫁接方法对麻栎嫁接成活率、苗高及地径均具有显著影响。切接法嫁接成活率最高,达到90%;其次是劈接法,达到85%;其它3种方法的较低,其中腹接的为70%,插皮接的为65%,T字形芽接的为60%。不同嫁接方法各处理苗木高和地径大小依次为切接劈接=腹接T字形芽接=插皮接。     

Cloning of erect,thornless, non-browsed nitrogen fixing trees of Haiti's principal fuelwood species (Prosopis juliflora)

A progeny trial in Haiti compared 70 open-pollinated families ofProsopis representing seed sources from Haiti, Peru, Chile, Argentina and southwestern US. At the end of 4 years growth, the tallest 6 families were of Peruvian origin. Some of these Peruvian trees (probablyP. juliflora) were thornless, had erect habit and were non-browsed by goats, unlike other thornlessProsopis alba families from South America. Scions from the 5 tallest spineless and most erect trees were transported from Haiti to Texas A&I University where they were successfully grafted ontoP. alba rootstock. These scions should have great potential for grafting onto existing weedyProsopis and for grafting onto rootstock previously shown to tolerate salinities of seawater and pH values of 10.3.     

Carbon and nitrogen partitioning in peach/plum grafts

Modifications in root-shoot relationships induced by graft incompatibility were studied in peach/plum graft combinations by means of carbohydrate and nitrogen analyses and isotope labeling. Mobilization of stored carbon, phloem transport of carbon, and mobilization, assimilation and distribution of nitrogen were studied in one compatible peach/plum graft (Prunus persica L. Batsch cv. springtime grafted on Prunus cerasifera L. Ehrh cv. myrobalan P 2032) and one incompatible graft (Prunus persica L. Batsch cv. Springtime grafted on Prunus cerasifera L. Ehrh cv. myrobalan P 18) for 89 days after grafting. Carbon and nitrogen reserves were mobilized in the rootstock in both graft combinations during the first 78 days following grafting. After that, sorbitol concentration was lower in the roots of the incompatible graft than in the roots of the compatible graft, whereas soluble sugars and starch accumulated in the peach scion of the incompatible graft. In both graft types, carbon was allocated mainly to the scion. Labeling with (13)CO(2) from 78 to 81 days after grafting showed that carbon partitioning among the different plant organs was only slightly affected by graft incompatibility. Carbohydrate concentrations provided indirect evidence that carbon transfer to the roots was hindered in the incompatible graft. Labeling with (15)NO(3) showed that nitrogen distribution and the rate of nitrogen assimilation were similar in the two graft combinations from 57 to 78 days after grafting. Nitrogen assimilation in the incompatible graft ceased 78 days after grafting, whereas it continued in the compatible graft.     

油茶不同无性系嫁接育苗效果调查

以福建省油茶优良无性系M43、M48和M60为接穗,普通油茶芽苗为砧木,进行嫁接育苗;采用随机区组调查法对油茶不同无性系芽苗砧嫁接苗的育苗效果进行调查研究,结果表明:油茶不同无性系芽苗砧嫁接苗的成活率、成苗率的差异不明显,苗高、地径之间存在显著差异,高径比之间存在极显著差异。3个无性系嫁接苗成活率和成苗率分别为82.1%~84.9%和75.2%~79.8%,苗高和地径分别为9.62~11.67 cm和0.31~0.36 cm。。     

雪松嫁接技术试验

以马尾松为砧木的雪松嫁接技术试验表明:选用木质化程度高、生长健壮的马尾松1年生苗作砧木,基径以0.3~0.4 cm为宜;接穗为雪松1年生枝条,长度以10 cm、粗度以0.2~0.3 cm为宜;砧木与接穗粗度比例为1∶0.7;用形成层贴接法嫁接于砧木苗干基部6 cm范围内。试验共嫁接4 334株,成活率达85%。当年新梢生长50 cm,3年生苗高在2 m以上。     

Hydraulic architecture and photosynthetic capacity as constraints on release from suppression in Douglas-fir and western hemlock

We compared hydraulic architecture, photosynthesis and growth in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), a shade-intolerant species, and western hemlock (Tsuga heterophylla (Raf.) Sarg.), a shade-tolerant species, to study the temporal pattern of release from suppressive shade. In particular, we sought to determine whether hydraulic architecture or photosynthetic capacity is most important in constraining release. The study was conducted at two sites with mixed stands of 10- to 20-year-old Douglas-fir and western hemlock. At one site, the stand had been thinned allowing release of the understory trees, whereas at the other site, the stand remained unthinned. Douglas-fir had lower height growth (from 1998-2003) and lower relative height growth (height growth from 1998 to 2003/height in 1998) than western hemlock. However, relative height growth of released versus suppressed trees was higher in Douglas-fir (130%) than in western hemlock (65%), indicating that, although absolute height growth was less, Douglas-fir did release from suppression. Release seemed to be constrained initially by a limited photosynthetic capacity in both species. Five years after release, Douglas-fir trees had 14 times the leaf area and 1.5 times the leaf nitrogen concentration (N (area)) of suppressed trees. Needles of released western hemlock trees had about twice the maximum assimilation rate (A (max)) at ambient [CO(2)] as needles of suppressed trees and exhibited no photoinhibition at the highest irradiances. After release, trees increased in leaf area, leaf N concentration and overall photosynthetic capacity. Subsequently, hydraulic architecture appeared to constrain release in Douglas-fir and, to a lesser extent, in western hemlock. Released trees had significantly less negative foliar delta(13)C values than suppressed trees and showed a positive relationship between leaf area:sapwood area ratio (A (L)/A (S)) and delta(13)C, suggesting that trees with more leaf area for a given sapwood area experienced a stomatal limitation on carbon gain. Nonetheless, these changes had no significant effects on leaf specific conductivities of suppressed versus released trees of either species, but leaf specific root conductance was significantly lower in released Douglas-fir.     

油茶芽苗砧嫁接试验

以桃江县采穗圃油茶良种材料为接穗,桃江县苗圃培育的芽苗为砧木,采用随机区组设计,进行油茶芽苗砧嫁接试验。结果表明:采用1∶1 000的甲基托布津溶液处理芽苗后嫁接,较清水处理的对照成活率高25.8%,生长量高11.7%;采用穗条的顶芽、中部芽、下部芽进行嫁接,其嫁接苗的成活率分别为88.4%、83.2%、72.2%,嫁接149 d后,其苗高分别为8.9、8.5、8.1 cm;于芽苗砧的芽部和根部进行嫁接,其嫁接苗的成活率分别为85.2%和85.8%,嫁接149 d后,其苗高分别为8.55、7.10 cm。     

云南果梅良种优质苗木的培育技术

采用良种壮苗是果梅优化栽培的物质基础。通过在云南丽江南口苗场进行的嫁接育苗试验,摸索出一套云南果梅良种优质苗木的培育技术。本文按育苗程序,从优良品种类型母树的选择,梅砧及嫁接苗的培育上详尽地介绍了云南果梅良种优质苗木的培育技术。采用此套技术,培育砧苗出苗率高,生长健壮,经采用优株穗条嫁接,嫁接成活率高,嫁接苗生长也健壮。达到了培育果梅良种优质壮苗的目的。     

京东板栗低产树改接优良品种当年丰产技术研究

为解决遵化市部分实生老栗树产量极低、存在部分低产栗园等问题,于2012年在遵化市马兰峪镇魏进河板栗园进行了低产板栗树高接换优试验。结果表明,通过改接燕山早丰、遵化短刺和紫珀等优良品种,嫁接成活率达到了97．6％～98．2％,改接当年3个品种单株产量分别为1．77kg、1．83k和1．84kg,极显著高于对照;改接第2年3个品种单株产量分别为3．0kg、3．2kg、2．8kg,极显著高于对照,其中以改接遵化短刺产量最高,实现了改接当年丰产、第2年高产。     

接穗留叶数对油茶芽苗砧嫁接愈合过程的影响

为了研究接穗留叶数与嫁接愈合、嫁接苗成活及苗木生长的关系,从而为油茶嫁接育苗提供技术指导,以油茶优良无性系长林4、40、18、23号的接穗为试验材料,采用完全随机试验设计,将接穗保留的叶子数量分别设为0.5、1.0、2.0、3.0片,就不同接穗留叶数处理对嫁接愈合过程及愈合过程中嫁接苗的各项生理及形态指标的影响情况进行了试验研究。结果表明:不同接穗留叶数处理均可改变嫁接苗的愈合速率,但均未改变愈伤组织的形成过程,在其愈合过程中,愈伤比例最大的接穗品种为40号,其次分别是4号与23号,愈伤比例最小的为18号,接穗分别保留叶子0.5、1.0片的愈合均最快;不同接穗留叶数处理对愈合过程中嫁接苗的可溶性糖、可溶性蛋白含量及POD活性的影响均不大;不同处理嫁接苗的苗高、地径、成活率的大小顺序为:留叶1.0片留叶0.5片留叶2.0片留叶3.0片。文中综合分析认为,供试的4个接穗品种中,40号最优,其次是4号,然后是23与18号;建议生产中将接穗保留1.0片叶子进行嫁接。     

An investigation of hydraulic limitation and compensation in large,old Douglas-fir trees

The hydraulic limitation hypothesis (Ryan and Yoder 1997) proposes that leaf-specific hydraulic conductance (kl) and stomatal conductance (gs) decline as trees grow taller, resulting in decreased carbon assimilation. We tested the hydraulic limitation hypothesis by comparison of canopy-dominant Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) trees in stands that were approximately 15 m (20 years old), 32 m (40 years old) and 60 m (> 450 years old) tall in Wind River, Washington, USA. Carbon isotope discrimination (Delta) declined with tree height (18.6, 17.6 and 15.9 per thousand for stands 15, 32 and 60 m tall, respectively) indicating that gs may have declined proportionally with tree height in the spring months, when carbon used in the construction of new foliage is assimilated. Hydraulic conductance decreased by 44% as tree height increased from 15 to > 32 m, and showed a further decline of 6% with increasing height. The general nonlinear pattern of kl versus height was predicted by a model based on Darcy's Law. Stemwood growth efficiency also declined nonlinearly with height (60, 35 and 28 g C m-2 leaf area for the 15-, 32- and 60-m stands, respectively). Unlike kl and growth efficiency, gs and photosynthesis (A) during summer drought did not decrease with height. The lack of decline in cuvette-based A indicates that reduced A, at least during summer months, is not responsible for the decline in growth efficiency. The difference between the trend in gs and A and that in kl and D may indicate temporal changes (spring versus summer) in the response of gas exchange to height-related changes in kl or it may be a result of measurement inadequacies. The formal hydraulic limitation hypothesis was not supported by our mid-summer gs and A data. Future tests of the hydraulic limitation hypothesis in this forest should be conducted in the spring months, when carbon uptake is greatest. We used a model based on Darcy's Law to quantify the extent to which compensating mechanisms buffer hydraulic limitations to gas exchange. Sensitivity analyses indicated that without the observed increases in the soil-to-leaf water potential differential (DeltaPsi) and decreases in the leaf area/sapwood area ratio, kl would have been reduced by more than 70% in the 60-m trees compared with the 15-m trees, instead of the observed decrease of 44%. However, compensation may have a cost; for example, the greater DeltaPsi of the largest trees was associated with smaller tracheid diameters and increased sapwood cavitation, which may have a negative feedback on kl and gs.     

Needle anatomy changes with increasing tree age in Douglas-fir

Morphological differences between old-growth trees and saplings of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) may extend to differences in needle anatomy. We used microscopy with image analysis to compare and quantify anatomical parameters in cross sections of previous-year needles of old-growth Douglas-fir trees and saplings at the Wind River Canopy Crane site in Washington and at three sites in the Cascade Mountains of Oregon. We also compared needle anatomy across a chronosequence of 10-, 20-, 40- and 450-year-old Douglas-fir trees from the Wind River site. Anatomy differed significantly between needles of old-growth trees and saplings at all sites, suggesting a developmental change in needle anatomy with increasing tree age. Compared with needles of old-growth trees, needles of saplings were longer and had proportionately smaller vascular cylinders, larger resin canals and few hypodermal cells. Astrosclereids, which sequester lignin in their secondary cell walls and occupy space otherwise filled by photosynthetic cells, were scarce in needles of saplings but abundant in needles of old-growth trees. Needles of old-growth trees had an average of 11% less photosynthetic mesophyll area than needles of saplings. The percentage of non-photosynthetic area in needles increased significantly with increasing tree age from the chronosequence of 10-, 20-, 40- and 450-year-old trees at the Wind River site. This reduction in photosynthetic area may contribute to decreased growth rates in old trees.     

早实核桃芽接愈伤形成过程扫描电镜观察

为给完善核桃芽接繁育技术提供参考,选用山东地方品种‘鸡爪绵’核桃实生苗为砧木,采用大方块芽接方法嫁接早实核桃品种‘香玲’和‘元林’,利用扫描电镜观测其砧穗组合体愈伤形成和嫁接口愈合过程。结果表明:2个早实核桃品种嫁接愈合过程相似,嫁接后第6天砧穗嫁接体愈合完成。第1天,嫁接口接穗上有愈伤组织细胞产生,同时有少量无机、有机分泌物或晶体;第2天,嫁接口处产生大量愈伤组织细胞,‘香玲’和‘元林’接穗愈伤组织细胞直径分别为17.5~35.0和14.1~33.3μm,‘元林’接穗愈伤细胞数量明显多于‘香玲’;第4天,愈伤细胞延伸分化出明显的愈伤组织,愈伤组织不断分裂;第5天,砧穗愈伤组织相互交叉连接;第6天,接穗和砧木间的维管束已重新连接,嫁接愈合完成。     

不同嫁接处理对杜鹃红山茶嫁接成活率的影响

为提高杜鹃红山茶（Camellia azalea）嫁接成活率,增加苗木产量,降低生产成本,实现苗木 培育批量化提供科学依据,通过山茶属砧木种类、存储时间、嫁接时间、种植环境（温室大棚和大田阴 棚,单一基质和混合基质）等不同嫁接处理的杜鹃红山茶嫁接扩繁试验,运用多重比较对嫁接成活率进 行研究。结果表明：不同树种砧木杜鹃红山茶嫁接成活率存在显著差异（P<0.05）,油茶（C. oleifera）幼 嫩芽苗和高州油茶（C. gauchowensis）嫁接成活率显著高于攸县油茶（C. yuhsienensis）幼嫩芽苗和广宁红 山茶（C. semiserrata）营养袋苗,高州油茶半木质化的芽苗砧和芽苗根砧嫁接成活率也显著高于油茶和攸 县油茶幼嫩芽苗;同种树种的芽苗根砧和芽苗砧嫁接,5 月和9 月嫁接的成活率影响不显著;随取随用砧 木比存储砧木,砂壤土基质比混合基质（体积比为50% 砂壤土+50% 泥炭土）,温室大棚比大田阴棚的嫁 接成活率高。综合评价结果显示：以高州油茶半木质化芽苗砧为砧木嫁接杜鹃红山茶,种植在室内大棚 的砂壤土基质中,嫁接成活率最高可达90.1%,且砧木利用率提高一倍,节约了砧木资源,可在生产中推 广应用。