马占相思优树组培苗扦插技术研究

以1～2年生马占相思优良无性系组培苗为材料，进行了生根基质、生根剂浸泡液、插穗来源等扦插试验研究。结果表明：基质以泥炭土最好，生根率达83．0％，含泥炭土的混合基质效果次之，生根率为76．5％；3种生长素作生根剂单独使用时，以IAA800mg／L浓度浸泡效果最好，生根率达67．0％，NAA、IBA浓度超过200mg／L时效果较差；不同继代组培母株和定植1～2年生母株的插穗，生根率均有显著差异，不同枝段位置1年生母株差异不显著，2年生母株中间幼嫩节段生根率大于顶芽，因此在实际生产中中间幼嫩节段也可作为有效插穗使用。     

马占相思扦插快繁育苗技术研究

通过双因素试验设计研究了3种不同木质化程度插穗(A)、4种不同浓度生根促进剂ABT-1#(B)和不同扦插基质(C)对马占相思扦插生根率、生根数及根长的影响差异,结果表明:未木质化的嫩枝(A1)+生根促进剂ABT-1#400 mg.kg-1(B2)生根率高、生根数多及生根长,生根率最高达83.3%;不同基质扦插中以未木质化的嫩枝(A1)+生根促进剂ABT-1#400 mg.kg-1(B2)+80%红心土和20%珍珠岩混合基质最佳。     

马占相思网袋容器轻型育苗基质扦插生根能力比较

采用双因素完全随机区组设计,研究8种网袋容器轻型育苗基质及3种插穗下切口型对马占相思扦插生根率的影响。结果表明,以泥炭∶木屑∶树皮∶红心土=3∶3∶3∶1,配合插穗基部双削面切口型效果最好,平均生根率达到85.3%。     

马占相思拟组培扦插生根研究

为建立马占相思(Acacia mangium)拟组培扦插生根技术体系,于8月采马占相思采穗圃当年生腋芽饱满枝条为穂条,以琼脂和适宜的抑菌剂制成的固体培养基为扦插基质,筛选出适宜的抑菌剂种类及浓度、以及适宜的插条类型和消毒方式;对IBA、NAA、ABT 3种生根促进剂的浓度进行筛选,以确定适宜的扦插生根处理。结果表明:百菌清0.2 g/L为适宜的抑菌处理,多菌灵0.8 g/L对中部带叶插条浸泡3 min后,以IBA 0.6 g/L浸泡其基部2 h,实验台操作,扦插至基质中,生根率94.33%。将马占相思开放扦插于简化的基质中,在组培室中培养生根,建立的拟组培扦插技术体系,由于插条长度更短,穂条利用率获得极大提高;室内进行扦插,可多层放置,极大地节约了空间;因此,成本更低,更易于推广应用;同时也为其他林木树种开展相关研究提供很好的借鉴。     

马占相思种子繁殖技术研究

通过试验研究不同基质（A）和不同基肥（B）对马占相思种子繁殖成活率、苗高、地径及生根数的影响差异;结果表明：马占相思种子繁殖使用（55％红心土＋30％火烧土＋15％发酵牛粪）基质（A4）和施用六国通用型复合肥作基肥（B2）效果最佳,平均成活率达91．3％、苗高16．8em、地径达2．6mm、生根数达12．3条。     

卷荚相思扦插繁殖试验

通过正交试验设计研究不同生根促进剂和浓度对不同木质化程度的卷荚相思穗条扦插繁殖生根率、不同栽培基质对卷荚相思扦插繁殖生根率的影响。结果表明:未木质化的嫩枝以IBA 600×10-6+ABT-1#600×10-6处理的生根率高、生根数多、生根长和苗高;3种基质的对比试验中以100%红心土表现最好。     

黑木相思扦插育苗技术研究

通过正交试验设计研究不同生根促进剂及浓度和不同种类的扦插基质对黑木相思嫩枝扦插生根的影响；研究了不同扦插时间对黑木相思生根率的影响。结果表明,黑木相思嫩枝使用ABT1~＃500×10~(-6) ZBA400×10~(-6) 100%红心土为扦插基质的组合生根率高,生根数多,根生长长度长；一年中以4～6月份扦插生根率最高。     

杂交相思扦插繁殖试验

通过对杂交相思不同类型插条、不同生根剂种类及不同基质扦插试验研究,结果表明:嫩枝扦插生根率高、平均根数多、根长;生根试剂对扦插作用效果不明显;扦插基质以黄心土生根率最高;扦插时间以4-6月生根率最高。     

黑木相思嫩枝扦插繁殖试验

通过正交试验设计研究不同的切穗条件、扦插基质、生根促进剂对黑木相思生根率和不定根根数、不定根根长的影响：结果表明，切穗条件对生根率影响最大，其次是扦插基质：各因素的最佳组合为：在流水中切穗，利用ABT-6号生根粉200mg／L浸泡3h，扦插在蛭石基质中。     

厚荚相思扦插繁殖试验研究

通过正交试验设计研究不同生根促进剂和浓度处理不同木质化程度的厚荚相思穗条对扦插繁殖生根率、生根数、生根长度及苗高的影响;研究了不同基质对厚荚相思扦插生根的影响差异,还研究了不同时间扦插对厚荚相思生根率的影响。结果表明,嫩枝使用450 mg.kg-1ABT 1#+450 mg.kg-1IBA生根率高,生根数多;3种基质对比试验中以100%红心土生根率最高;不同时间扦插中以4~6月份生根率最高。     

马占相思开花生物学特征研究

利用光学显微镜和扫描电子显微镜（SEM）,对马占相思开花物候、花部形态和传粉效率等进行了研究。结果表明：马占相思于9-11月开花,整个群体花期有6 7个小花期;单株开花同步性强,呈现“集中开花”模式;穗状花序由172.7±27.1朵花组成,每个花序平均有（10.35±7.78）%的雄花,两性花具有雌蕊１枚,含14.11±1.05粒胚珠;柱头凹陷,大小可容纳1 2粒直径为29 35 μm的16合花粉粒,P/O’为1.13/1;马占相思开花时,雌蕊先于雄蕊伸展并成熟,为雌蕊先熟;SEM结果显示：花药在开花第2、3阶段仅有开裂线,在第4阶段之后才开裂,即7：00－9：00开裂,9：00－12：00大量散粉;柱头在开花第1天上午可观察到分泌物,预示柱头可授。此研究结果将为今后加强相思种子园的管理及开展相思杂交育种奠定重要基础。     

Facilitation by two exotic Acacia: Acacia auriculiformis and Acacia mangium as nurse plants in South China

Because of their high growth rate and tolerance to bare soil, two exotic Acacia species, Acacia auriculiformis and Acacia mangium, have been commonly planted in degraded areas of South China. With their large canopies and ability to fix nitrogen, the two Acacia species have also been considered to act as nurse plants for understory plants. The current study clarified the nursing effects of the Acacia species by comparing microclimate characteristics and physiological traits of native plant seedlings at three sites: under the canopies of the each Acacia species and on bare land (open site). Although the sites were not replicated, the results indicated that adult trees of both Acacia species can facilitate native species, but that A. mangium has greater facilitating effects due to greater temperature buffering, radiation reduction, and nutrient amelioration. In response to facilitation, three species (Castanopsis hystrix, Michelia macclurei, and Manglietia glauca) with different shade-tolerant traits growing under Acacia canopies expressed distinct adaptations. For the three species, the chlorophyll fluorescence curves of rETR and ΔF/Fm′ were higher under A. auriculiformis and on the open site than under A. mangium. The maximum quantum yield in PSII(Fv/Fm) in diurnal changes of the three species showed that all the Fv/Fm values were between 0.70 and 0.84 and that the Fv/Fm values were mostly higher under A. mangium than on the open site or under A. auriculiformis. Total chlorophyll content and both chlorophyll a and b contents in the three species were higher under the Acacia species than on the open site, while chlorophyll a/b ratio was higher on the open site. In contrast, the carotenoid content in C. hystrix and M. macclurei was lower under the two Acacia species than on the open site, while the opposite was true for M. glauca. The results demonstrate that the adaptation of the understory species to abiotic environmental factors is not restricted to a single mechanism but apparently involves a group of interrelated, adaptive suites. And also these adaptations were species-specific and especially related to their shade tolerance.     

Soil changes induced by Acacia mangium plantation establishment: Comparison with secondary forest and Imperata cylindrica grassland soils in South Sumatra,Indonesia

Acacia plantation establishment might cause soil acidification in strongly weathered soils in the wet tropics because the base cations in the soil are translocated rapidly to plant biomass during Acacia growth. We examined whether soils under an Acacia plantation were acidified, as well as the factors causing soil acidification. We compared soils from 10 stands of 8-year-old Acacia mangium plantations with soils from 10 secondary forests and eight Imperata cylindrica grasslands, which were transformed into Acacia plantations. Soil samples were collected every 5–30 cm in depth, and pH and related soil properties were analyzed. Soil pH was significantly lower in Acacia plantations and secondary forests than in Imperata grasslands at every soil depth. The difference was about 1.0 pH unit at 0–5 cm and 0.5 pH unit at 25–30 cm. A significant positive correlation between pH and base saturation at 0–20 cm depth indicated that the low pH under forest vegetation was associated with exchangeable cation status. Using analysis of covariance (ANCOVA), with clay content as the covariate, exchangeable Ca (Ex-Ca) and Mg (Ex-Mg) stocks were significantly lower in forested areas than in Imperata grasslands at any clay content which was strongly related to exchangeable cation stock. The adjusted average Ex-Ca stock calculated by ANCOVA was 249 kg ha⁻¹ in Acacia plantations, 200 kg ha⁻¹ in secondary forests, and 756 kg ha⁻¹ in Imperata grasslands at 0–30 cm. Based on a comparison of estimated nutrient stocks in biomass and soil among the vegetation types, the translocation of base cations from soil to plant biomass might cause a decrease in exchangeable cations and soil acidification in Acacia plantations.     

马占相思优树组培快繁技术研究*

相思(Acacia Mill.)类树种(俗称相思树)属含羞草科(Mimosaceae)金合欢属(Acacia Mill.),在我国广东、海南、广西、福建、云南和江西等地均有栽培。相思树植株高大挺拔,根系发达具根瘤,具有耐干旱贫瘠及抗风的特性,是水土保持及改良土壤的优良树种;同时,相思树还是优良的用材树种,其生     

中国特有濒危植物崖柏扦插繁殖研究

在重庆市城口县咸宜乡苗圃和中国林科院温室开展崖柏扦插繁殖试验,研究采穗母树年龄、不同激素种类及其组合、激素浓度、扦插基质、物理促根等不同处理方式下崖柏扦插生根效应.结果表明:(1)在咸宜乡苗圃,采用自动喷雾设施,以蛭石-泥炭土-珍珠岩(1∶1∶1)为扦插基质,用3种激素和清水处理崖柏幼树1年生枝条,扦插后160d的生根率为74.76％～96.70％,不同处理组合生根效应具有显著差异,2000 mg· L-1 IBA＞清水对照(CK)＞1 000mg·L-1 IBA＞1 000 mg·L-1IBA+ 500 mg· L-1NAA;(2)在林科院温室用2种激素和清水处理崖柏幼树1年生枝条,扦插于蛭石-泥炭土-珍珠岩(1∶1∶1)的基质,搭塑料拱棚,扦插后120 d的生根率远低于咸宜乡苗圃,为25.93％～45.37％,激素处理后的枝条与对照差异显著,1 000 mg·L-1 IBA+ 50 mg·L-1 NAA=2 000 mg·L-1 IBA＞清水对照(CK);(3)在咸宜乡苗圃用不同激素和物理促生根方法组成的27种组合处理的成年崖柏枝条,最高生根率仅为20.83％.生根率超过10％的处理组合是:清水处理,泥炭土∶蛭石∶珍珠岩(1∶1∶1);1 000 mg·L-1IBA+500 mg·L-NAA,泥炭土∶珍珠岩(2∶1);1 000 mg·L-1IBA,泥炭土∶蛭石∶珍珠岩(1∶1∶1),流水冲洗.     

卷荚相思组培快繁技术研究

[目的]建立16年生卷荚相思优树组培快繁技术体系。[方法]以16年生卷荚相思优树的当年新生枝条带腋芽茎段为材料,对卷荚相思外植体进行消毒、初代培养、增殖培养、生根培养和移植等。[结果]表明:通过对16年生卷荚相思成年优树采条进行扦插,以扦插苗建立采穗圃,选取采穗圃中当年生健康无病虫害枝条的中段为外植体,最佳消毒方式为75%的酒精处理0.5 min和0.1%的升汞处理18 min,其存活率达69.33%,芽诱导率达86.67%;最佳初代培养基为改良MS+蔗糖40 g·L-1,出芽率为91.33%。最佳增殖培养基为MS+6-BA 0.5 mg·L-1+NAA 0.1 mg·L-1+蔗糖30 g·L-1,35 d增殖倍数可达3.50倍;最佳生根培养基为1/2 MS+IBA 0.25 mg·L-1+NAA 0.5 mg·L-1+蔗糖40 g·L-1,15 d生根率为96.11%;将生根苗移植至以沙为基质的营养杯中,存活率为71.11%。[结论]研究解决了16年生卷荚相思成年优树外植体污染率高和芽诱导率低等问题,建立的组培快繁技术体系对今后加快卷荚相思良种选育及优质苗木大量扩繁具有重要作用。     

Mixed-species plantations of Acacia mangium and Eucalyptus grandis in Brazil: 1. Growth dynamics and aboveground net primary production

Nitrogen fertilizer inputs increased sharply over the last decade in Brazilian eucalypt plantations. Due to the economic and potential environmental cost of fertilizers, mixed plantations with N-fixing species might be an attractive option to improve the long-term soil N status. A randomized block design was set up in southern Brazil, including a replacement series and an additive series design, as well as a nitrogen fertilization treatment. The development of mono-specific stands of Eucalyptus grandis (0A:100E) and Acacia mangium (100A:0E) was compared with mixed plantations in proportions of 1:1 (50A:50E), and other stands with different densities of acacia for the same density of eucalypts. The objective was to assess the effect of inter-specific interactions on the early development of the two species. Aboveground biomass was measured 6, 12, 18 and 30 months after planting, sampling 6–10 trees of each species per treatment at each age, and allometric equations were established in 0A:100E, 100A:0E, 50A:50E and 50A:100E. The height and basal area of E. grandis seedlings were enhanced by 12% and 30%, respectively by N fertilization at age 1 year. Inter-specific competition led to a stratified canopy, with suppression in acacia growth earlier for basal area than for height. The mean number of stems per acacia tree at 36 months after planting was significantly higher in pure stands (3.7), than in 50A:50E (2.7) and in the additive series (between 1.6 and 1.8). H/D ratios were highly sensitive to inter-tree competition for the two species. The suppressed acacia understorey in mixed-species stands did not influence biomass production and partitioning within eucalypts. This pattern led to biomass accumulation combining the two species in 50A:100E that was about 10% higher than in 0A:100E, from age 12 months onwards. Aboveground net primary production (ANPP) amounted to 25 Mg ha⁻¹ and 37 Mg ha⁻¹ from age 18 to 30 months in 100A:0E and 0A:100E, respectively. Acacia ANPP in 50A:100E amounted to 2 Mg ha⁻¹ over the same period, as a result of substantial inter-specific competition. An increment in biomass production in these very fast-growing eucalypt plantations was achieved introducing acacia as an understorey and not in the 50A:50E design, as observed in other studies.     

干热河谷大叶相思树干液流季节动态及其与气象因子的关系

应用热扩散式探针法(TDP)对干热河谷主要造林树种大叶相思的树干液流进行了湿季(7-8月)和干季(1-3月)典型月连续监测,并结合自动气象站对周围气象要素进行同步测定,据此分析液流速率的昼夜、季节变化规律及其与气象因子的关系.结果显示:(1)无论是干季还是湿季,大叶相思树干液流均表现出明显的昼夜变化规律,即呈现“昼高夜低”典型的液流单峰曲线;(2)树干南面液流速率均高于北面,干季南、北方位液流速率最大相差0.0037 cm· s-1,湿季最大相差0.0014cm·s-1;(3)干、湿季液流平均值和最大值具显著差异,湿季树干液流速率平均值和峰值约为干季的2.8倍和2.5倍;(4)大叶相思树干液流速率与光合辐射强度、水汽压亏缺、大气温度、风速呈极显著的正相关关系,而与相对湿度呈极显著负相关关系,按相关程度排序为光合辐射强度＞大气温度＞水汽压亏缺＞相对湿度＞风速,其中,光合有效辐射、相对湿度、水汽压亏缺是影响液流速率的主导因子.     

花吊丝竹组培快繁育苗技术研究

The rapid propagation technology of Dendrocalamus minor var. amoenus was studied by investigating the effects of some factors such as selection of explant, phytohormone, culture method etc. The results show that: The best month for explant collection of D. minor var. amoenus is May and June. The best position for explant collection is middle-upper part knot of semi-lignification branch. The clump shoot could be induced in medium with 3/4MS+BA 4 mg·L^-1+KT 1 mg·L^-1+CW 100 mL·L^-1. The optimal medium for subculture of D. minor var. amoenus is 3/4MS+BA 2 mg·L^-1+KT 1 mg·L^-1+CW 100 mL·L^-1. Liquid medium is beneficial for improving growth condition and proliferation rate of clump shoot. The medium 1/5MS+IBA 8 mg·L^-1+ NAA 4.5 mg·L^-1 + KT 0.1mg·L^-1 is a relative suitable rooting medium for D. minor var. amoenus, with the rooting method of synchronized treatment first and then rooting. The survival rate of seedlings could be higher than 90% in substrate of fine river sand∶peat soil=3∶ 1.     

Asynchronous wood formation in youngAcacia mangium planted in Malaysia

In general, tropical trees have less-distinct growth rings. Even if the trees have some concentric structures, there is little information on the timing of their formation. The objective of this report is to show the asynchronous wood formation from the observation of indistinct, ring-like structures. YoungAcacia mangium planted in Malaysia was investigated for asynchronous wood formation anatomically and macroscopically. Tree heights and girths at breast height for 28 trees were measured every other week. Wood disks from four trees were sampled at breast height for this research. The radial variation of vessel dimensions and the number of cambial cells in different radial directions and the wood anatomy of discontinuous bands were investigated using thin sectioning and soft radiographic methods. The vessel dimension was quite different in their radial variation even for four radial directions with a similar radius. There was a large variation in the number of cambial cells among radial directions in youngAcacia mangium. Bands of low density included a layer of vessels aligned in a spiral rather than in a closed circle.