插穗因素对闽楠扦插苗生根、生长及相关酶活性的影响

选择40年生无病虫害闽楠植株半木质化枝条为插穗,采用L_8(2~7)正交试验方法,设置插穗来源(枝条顶部、枝条中部)、枝条长度(10cm、15cm)和留叶数(保留1片和2片全叶)3个插穗因素,研究插穗因素对闽楠扦插苗生根、生长及理化性质等方面影响,筛选适宜插穗处理方式,揭示插穗调控扦插苗生根和生长机理。结果表明:(1)闽楠插穗来源、长度及留叶数显著影响扦插苗的生根、生长及理化特性。(2)闽楠扦插最适合的插穗处理是取长度为10cm的中部枝、保留2片叶。(3)影响闽楠扦插生根率的最主要因素是插穗来源,关键生理指标是根系PPO和POD活性;影响闽楠扦插苗新梢生长最主要的因素是插穗的留叶数,关键生理指标是根系IAAO活性和MDA含量。研究表明,各插穗因素显著影响着闽楠扦插苗的生根及生长,并以长度10cm、保留2片的中部枝为插穗最佳;该研究结果为闽楠扦插繁殖技术制定和推广应用提供理论与技术指导。     

不同基质对多穗石柯扦插生根的影响

为了筛选适宜的多穗石柯(Lithocarpus polystachyus)扦插基质，以半木质化枝条为插穗，选取5种原料(园土、黄心土、泥炭土、河沙、椰糠)设置8个基质配方，并对各基质容重、总孔隙度、pH、电导率进行测定，探讨不同基质对多穗石柯扦插成活率、生根数量及根系长度的影响。结果表明，不同配方基质的理化性质不同，多穗石柯扦插成活率、根系数量和根系长度具有显著性差异；成活率、根系数量和根系长度与基质的理化性质存在显著相关，总孔隙度大的基质不利于多穗石柯扦插成活和根系生长，pH和电导率较低的基质中多穗石柯扦插成活率较高；基质园土:黄心土:河沙(1:1:1)最适宜多穗石柯扦插繁殖，扦插成活率最高，为86.75%，其次是基质黄心土:河沙(2:1)。     

千层金嫩枝扦插繁殖技术

本研究用L_(16)(4~5)正交试验方法,研究了基质、穗条长度、植物生长调节剂及其浓度对千层金嫩枝扦插生根率的影响.结果表明,基质和生长调节物质对生根率有极显著的影响,而植物生长调节剂浓度与穗条长度对生根率有显著的影响,4个因素对干层金嫩枝大田扦插生根率影响从大到小分别是基质、生长调节物质、植物生长调节剂浓度和穗条长度.用浓度100 mg/L的NAA浸泡9 cm插穗2 h,在混和基质上扦插,平均生根率可达92%,且生根及新梢抽出时间早,侧根数量多,扦插效果最好.     

杉木耐瘠薄优株无性系扦插生长适应性

对杉木Cunninghamia lanceolata耐瘠薄优良个体无性系不同主干茎段穗条在不同季节扦插的生长适应性进行研究。结果表明,带顶芽穗条扦插成活率高于不带顶芽主干茎段穗条,当年苗高、地径年生长量也达显著差异;不同季节扦插明显影响成活率与当年苗高、地径年生长量,在3月、5月扦插,当年生苗木高、地径生长超过国家标准,6月底扦插,苗木因生长期较短,苗木高、地径生长偏小。6月以前进行不带顶芽茎段扦插,当年培育苗木质量能达到杉木无性系国家标准的Ⅰ级苗,适宜进行不带顶芽茎段扦插培育,可有效提高扦插穗条的利用率,有利于无性系推广应用。     

不同修剪措施对薄壳山核桃枝条生长及枝条和叶片碳氮代谢物积累的影响

以薄壳山核桃品种‘马罕’（Caryaillinoensis‘Mahan’）的5年生嫁接苗为实验材料,研究枝条短截（1/4、1/3和1/2短截）以及枝条和主干的环剥和环割对其枝条生长及枝条和叶片中碳氮代谢物积累的影响。结果显示：经不同程度短截处理后,枝条萌芽率均显著高于对照（未经任何修剪）,新枝的数量、长度和直径也均不同程度高于对照,而比叶质量及叶绿素含量总体上与对照无显著差异;经1/2和1/3短截处理后,长度0-10cm和30cm以上的新枝比例明显提高;枝条和叶片中可溶性糖含量和C/N比均高于对照、全N含量均低于对照,枝条中淀粉含量低于对照而叶片中淀粉含量高于对照。经枝条环剥和环割处理后,枝条萌芽率和比叶质量均高于对照但无显著差异,枝条平均长度增长量和叶绿素含量均显著低于对照、枝条平均直径增长量均显著高于对照;枝条和叶片中可溶性糖和淀粉含量以及C/N比均高于对照,全N含量均低于对照。经主干环剥和环割处理后,枝条的萌芽率和平均直径增长量以及比叶质量均显著高于对照,枝条平均长度增长量和叶绿素含量均显著低于对照;枝条和叶片中可溶性糖和淀粉含量以及C/N比均高于对照,枝条中全N含量高于对照而叶片中全N含量则低于对照。此外,品种‘马罕’的结果枝长度为0-30cm,其中长度0-10cm的结果枝数量最多。研究结果表明：不同短截措施均能提高薄壳山核桃的萌芽率、促进新枝伸长和增粗;而枝条和主干的环剥和环割处理对枝条萌芽率无明显促进作用,但有利于枝条增粗;不同修剪措施总体上有利于其叶片及枝条中碳水化合物的合成和积累。总体上,1/3短截及枝条和主干的适度环剥可促进品种‘马罕’结果枝的形成。     

连翘全光喷雾扦插育苗试验

以连翘半木质化嫩枝作插条,进行了不同扦插时间、不同枝条扦插部位、不同浓度生根激素处理、不同扦插基质和不同喷雾次数等全光喷雾扦插育苗试验。结果表明:在7月中旬进行扦插,截取当年生半木质化枝条的中部或梢部作插条,扦插前用浓度300～500 mg/kg的ABT-6号生根粉浸泡枝条基部0.5 h,以沙壤土作扦插基质,保持每天7～9次喷雾次数,能缩短连翘愈伤组织形成时间,显著提高生根数和生根率。     

芳樟无性系叶精油及芳樟醇含量变异分析

芳樟[ Cinnamomum camphora var.linaloolifera Fujita.]个体自然结果率极低,甚至只开花不结实,而其群体结果率却较高[1].通过自然授粉繁殖的芳樟子代叶精油类型(主要成分)存在分离现象,如叶精油主含芳樟醇的母株,可产生叶精油主含樟脑和桉叶油素的有性后代,且后代个体间芳樟醇含量差异大[2].而以此为原料提取的精油实为杂樟油,提纯难度大,市场价格受到严重影响,因此利用无性系收割枝叶方式进行芳樟香料林产业化开发受到广泛重视[3].精油为植物次生代谢物,其含量及组成受遗传和环境因子双重控制[4-6],因而,使芳樟优良无性系叶精油及其主成分保留母株的优良特性并保持稳定,是实现芳樟产业化开发的关键.作者对优良芳樟组培和扦插无性系叶精油及芳樟醇含量进行了测定,并分析其变异状况,以期为芳樟产业化开发提供实验数据.     

浙江红花油茶嫩枝扦插育苗技术初步研究

采用正交设计法进行田间试验,研究ABT1#生根粉不同的浓度、处理时间对浙江红花油茶嫩枝不同部位扦插成活的影响。结果表明：ABT1#生根粉处理可显著提高浙江红花油茶嫩枝插穗成活率,是影响扦插成活的关键因素。筛选出成活率最高的组合是A2B2C1,即：100 mg/L ABT1#生根粉处理浙江红花油茶嫩枝穗条梢段2 h。浙江红花油茶属于愈伤组织生根类型。     

丽江乡土植物头状四照花扦插繁殖试验

通过对丽江地区头状四照花繁育调查、形态学和气候分析,采用不同扦插时间和枝条年龄进行丽江乡土植物头状四照花扦插试验,结论为上半年最适合扦插时间为4月中旬,一年生枝条扦插成活率明显高于多年生枝条扦插成活率。     

裸花紫珠嫩枝扦插生根影响因子研究

以2年生实生苗的嫩枝为试材,从基质、插条部位、留叶方式、扦插季节、外源激素种类及浓度5个方面对裸花紫珠的扦插生根因子进行了系统研究。测定插穗的生根率、偏根率、生根数量及最大根长,采用隶属函数值对扦插生根效果进行综合评价。结果表明:(1)8个基质处理中,以泥炭∶蛭石∶河沙按2∶1∶1体积比混合的基质扦插效果最好,生根率74%,平均生根数5.4条;(2)插条中、上部制取的插穗扦插效果优于下部,且中部插穗的生根质量最佳;(3)插穗留叶处理的生根率显著高于不留叶处理,留两片半叶(1/2叶)时,生根率可达64%;(4)秋季(9月)为扦插最适宜季节,生根数量和最大根长均显著高于春季(4月)和夏季(7月);(5)4个浓度下,IBA处理的生根质量均高于IAA和NAA处理,其中IBA(1 000、1 500 mg·L~(~(-1)))处理的扦插效果较好,而高浓度NAA(2 000、2 500 mg·L~(~(-1)))处理明显不利于生根。     

不同栽培技术对芳香樟穗条产量的影响

为营建芳香樟高产采穗圃,提供优质穗条,对采穗圃采取截干、施肥试验,分析不同栽培技术对穗条产量和质量的影响。结果表明,截干高度以低台式修剪的穗条产量最高,且穗条短粗,质量较好,而中柱式效果次之,高柱式效果最差;截干时间以7月或3月初效果较好,5月中旬最差;施肥时间以3月和8月各施肥1次效果最佳。     

不同处理对濒危植物黄枝油杉扦插育苗的影响

黄枝油杉属珍稀濒危植物,树形高大,采种困难,母树开花结实少,种子发芽率低,繁殖速度慢。采用扦插育苗,方法简便易行,繁殖速度快。为此,针对与黄枝油杉扦插育苗成活、生长密切相关的插穗粗度、ABT生根粉浓度和施肥种类三大因素,分别进行对比试验。结果表明:插穗茎粗0.70cm用150mg/LABT生根粉溶液处理的平均成活率达95.6%;扦插成活后施用粪肥+尿素(配比为100∶0.4)的混合肥苗木生长健壮,平均抽梢长达30.8cm。方差分析和多重比较分析结果表明,插穗粗度、ABT生根粉浓度和肥料种类对黄枝油杉扦插苗木的生长影响极大。     

Shoot growth phenology of co-existing evergreen and deciduous species in an oak forest

Shoot growth phenology was compared for the saplings of evergreen and deciduous woody species sharing the same microsite. Growth initiation occurred earlier in evergreens (among co-stratal species) while deciduous species completed their growth earlier. Shoot growth rate was significantly greater (P<0.01) for deciduous trees than evergreen trees. The amount of shoot elongations and shoot diameter was also significantly greater (P<0.01) for deciduous trees than evergreens. On the other hand, among shrubs the amount of shoot elongation and shoot diameter was greater for evergreens but the rate of elongation and diameter was more or less similar for both. The duration of shoot elongation and shoot diameter was significantly longer in evergreens than the deciduous species. Leaf packing (number of leaves per shoot) was significantly more dense in evergreen trees (P<0.01) than in deciduous tree species. Leaf packing was more dense in evergreen than deciduous shrubs but the difference was not significant. Leaf area (per individual leaf) at full expansion was significantly greater (P<0.01) in deciduous species. Leaf dry mass and specific leaf mass in the initial stage was significantly greater for evergreen species than for deciduous species. The number of buds/10 cm of shoot was higher in evergreens. However, the per cent mortality was also higher in them.     

Effect of Previous Defoliation Regime and Mineral Nitrogen on Regrowth in White Clover Swards: Photosynthesis, Respiration, Nitrogenase Activity and Growth

Small swards of white clover (Trifolium repens L.) cv. Haifawere grown in solution culture in a controlled environment at24 °C day/18 °C night and receiving 500 µE m^-2S^–1 PAR during a 14-h photoperiod. The swards were cuteither frequently (10-d regrowth periods) or infrequently (40-dregrowth) over 40 d before being cut to 2 cm in height. Halfof the swards received high levels of nitrate (2–6 mMN in solution every 2 d) after defoliation while the othersreceived none. Changes in d. wt, leaf area and growing pointnumbers were recorded over the following 10 d. CO₂ exchangewas measured independently on shoots and roots and nitrogenase-linkedrespiration was estimated by measuring nodulated root respirationat 21% and 3% oxygen in the root atmosphere. There was a general pattern in all treatments consisting ofan initial d. wt loss from roots and stubble and reallocationto new leaves, followed by a period of total d. wt gain andrecovery, to a greater or lesser extent, of weight in non-photosyntheticparts. Frequently cut swards had a smaller proportion of theirshoot d. wt. removed by cutting and had a greater shoot d. wt,growing point number and leaf area at the start of the regrowthperiod. As a result of these differences, and also because ofdifferences in relative growth rates, frequently cut swardsmade more regrowth than infrequently cut. Initial photosyntheticrates were higher in frequently cut swards, although the laminaarea index was very low, and it was concluded that stolons andcut petioles made a significant contribution to carbon uptakeduring the first few d. Infrequently cut swards continued toallocate carbon to new and thinner leaves at the expense ofroots and stubble for longer than frequently cut swards andas a result achieved a similar lamina area index after 10 d. Nitrogenase-linked respiration was low in all treatments immediatelyafter cutting: frequently cut swards receiving no nitrate maintainedhigh nitrogenase activity, whereas recovery took at least 5d in infrequently cut swards. Swards which received nitrateafter cutting maintained only low rates of nitrogenase-linkedrespiration and their total nodulated root respiration overthe period was lower than those receiving no nitrogen: greaterregrowth in nitrate fed swards over the 10 d compared to N₂-fixingswards was in proportion to this lower respiratory burden. White clover (Trifolium repens L.), defoliation, regrowth, nitrogen, photosynthesis, respiration, nitrogenase-activity     

Plant regeneration from leaf petioles in <Emphasis Type="Italic">Camptotheca acuminata</Emphasis>

Summary Camptothecin, produced by Camptotheca acuminata, is a pharmaceutically important compound. Transgenic technology has potential uses for the enhancement of camptothecin production; however, an efficient plant regeneration protocol for C. acuminata is not currently available. Factors that affected successful seedling germination were evaluated. The regeneration potential of various parts of seedlings was tested. Camptothecin production in regenerated plants was compared to its production in calluses and the original seedlings. Dark incubation and seed coat removal led to a higher germination rate and a higher survival rate after germination. The best shoot induction medium was found to be Gamborg's B5 medium+8.9 μM benzyladenine. Among the calluses induced from various parts of seedlings, leaf petiole calluses, leaf dise calluses, and cotyledon calluses regenerated shoots, but internode calluses did not. Furthermore, leaf petiole calluses and leaf dise calluses regenerated normal shoots, while cotyledon calluses regenerated hyperhydric shoots. Moreover, leaf petiole calluses had a higher shoot regeneration rate, 50% versus 9%, and a higher shoot number, 6.2±0.5 versus 2.0±0.3, than did leaf dise calluses on the best shoot induction medium. It took 4–6 wk to regenerate shoots after transfer into shoot induction media. Camptothecin concentration in the regenerated plants was significantly higher than that in the calluses and similar to that in the original seedlings. In conclusion, leaf petioles provide efficient plant regeneration of C. acuminata.     

Optimal central-place foraging by beavers: Tree-size selection in relation to defensive chemicals of quaking aspen

Summary At a newly occupied pond, beavers preferentially felled aspen smaller than 7.5 cm in diameter and selected against larger size classes. After one year of cutting, 10% of the aspen had been cut and 14% of the living aspen exhibited the juvenile growth form. A phenolic compound which may act as a deterrent to beavers was found in low concentrations in aspen bark, and there was no significant regression of relative concentration of this compound on tree diameter. At a pond which had been intermittently occupied by beavers for over 20 years, beavers selected against aspen smaller than 4.5 cm in diameter, and selected in favor of aspen larger than 19.5 cm in diameter. After more than 28 years of cutting at this site, 51% of the aspen had been cut and 49% of the living aspen were juvenileform. The phenolic compound was found in significantly higher concentrations in aspen bark than at the newly occupied site, and there was a significant negative regression of relative concentration on tree diameter. The results of this study show that responses to browsing by trees place constraints on the predictive value of standard energy-based optimal foraging models, and limitations on the use of such models. Future models should attempt to account for inducible responses of plants to damage and increases in concentrations of secondary metabolites through time.     

亚热带常绿阔叶林木本植物幼树阶段抽枝展叶的权衡关系

亚热带常绿阔叶林植物幼树阶段适应林内生境并开枝散叶是其长成大树的一个重要过程, 植物一年内多次抽枝的现象及其在抽枝展叶过程中小枝伸长、枝茎增粗与叶面积的增加优先顺序及其内在驱动机制还有待进一步研究。该研究对青城山常绿阔叶林木本植物多次抽枝发生比例进行了调查, 并以茶(Camellia sinensis)、细枝柃(Eurya loquaiana)、短刺米槠(Castanopsis carlesii var. spinulosa)、润楠(Machilus nanmu)和大叶山矾(Symplocos grandis) 5种植物的幼树为研究对象, 比较分析了植物在多次抽枝中小枝和叶片生长动态及适应策略的差异。结果显示: 1)一、二次抽枝分别开始于春季(4月)和夏末(8月下旬), 小枝水平上二次抽枝率乔木小于灌木, 常绿植物小于落叶植物。2)一次抽枝小枝枝长、单叶面积, 小枝直径和叶片数量(除大叶山矾外)均高于二次抽枝, 但二次抽枝单叶面积相对生长速率均高于一次抽枝, 二次抽枝叶片比叶质量(LMA)的增长速率高于一次抽枝。3)一次抽枝小枝枝长、叶片数量、小枝直径(除细枝柃和短刺米槠外)和总叶面积(除短刺米槠外)最大相对生长速率均高于二次抽枝, 且大部分物种最大相对生长速率出现在抽枝开始的第一、二周。4)两次抽枝中, 物种先侧重于叶片的生长, 其次是小枝枝长的生长, 最后是小枝直径的增粗。单叶面积和总叶面积皆随着小枝枝长和小枝直径的增加呈显著的异速生长关系, 表明叶片的增长速度大于小枝。单叶面积与叶片数呈显著大于1的异速生长关系, 暗示单叶面积的增长速度大于叶片数的增加速度。小枝枝长与小枝直径也呈显著大于1的异速生长关系, 揭示小枝枝长的增长速度大于小枝直径。综上所述, 两次抽枝过程中, 植物枝叶的优先生长顺序反映了植物为获取更多的资源(尤其是光源)而形成特定的抽枝展叶策略; 二次抽枝单叶面积相对生长速率和LMA增长速率高于一次抽枝, 这可能与植物即将面临的昆虫取食和气温降低压力有关。因此, 了解植物抽枝策略对于理解物种生态适应机制, 揭示物种生活史过程中存在的权衡关系具有重要的理论意义。     

海南岛霸王岭热带季雨林树木的死亡率

树木死亡是调节群落组成和结构的一种方式, 在森林生态系统动态中发挥着重要作用。该文在对海南岛霸王岭热带季雨林群落大量调查和树种功能群划分研究的基础上, 探索了热带季雨林群落及其不同功能群树木的死亡率及其随径级和环境条件的变化规律。结果表明: 海南岛霸王岭热带季雨林群落内树木死亡率的变化范围为3.42%-18.71%, 平均值为7.60%。按照功能群比较, 乔木死亡率显著高于灌木, 落叶树种死亡率高于常绿树种, 但具刺树种死亡率显著低于无刺树种。按照树木径级划分, 5-30 cm径级范围的死亡率均超过10%, 最高值出现在5-10 cm径级范围, 在相同径级范围内比较时, 落叶树种在 胸径(DBH ) < 5 cm时的死亡率显著高于常绿树种, 而在其他径级范围内, 二者之间无显著差异, 具刺和无刺树种的死亡率在所有径级范围内均无显著差异。乔木死亡率与群落距河流距离具有显著的相关性, 距离河流越远死亡率越高; 落叶树种和无刺树种则与坡位存在显著的相关性, 坡上部的死亡率显著高于坡中部。热带季雨林内树木的死亡率与其所处的群落生境有关, 较干旱的生境是导致树木死亡率较高的重要原因。