滨海沙地木麻黄(Casuarina equisetifolia)人工林细根养分与能量动态

2005年1月到2005年11月对福建省惠安县赤湖林场不同林龄木麻黄人工林细根养分和能量的季节动态进行了观测,结果表明:(1)6种元素的含量在不同林龄木麻黄细根中都具有明显的季节变化。各林龄细根的N含量一般在冬夏季节较高,且死细根的N浓度高于相同林龄的活细根,除12林龄活细根P浓度在7月份有最大值外,其他各林龄活、死细根在一年中呈波动性下降,K含量在冬季较高,而在其他季节变化幅度不大,除5林龄活细根和18林龄死细根在3月份和7月份有两个峰值外,其他林龄细根Ca含量随季节变化较小,Mg含量随季节变化总体呈下降趋势,而在11月份上升;各林龄C则呈波浪形变化;(2)随着林龄的增大,细根N、P、Mg含量的变化模式相似,都呈先增加,后降低,再增加的趋势,K和Ca含量变化趋势相似,但变动幅度存在差别,C则呈波浪形变化;(3)随着季节的变化,灰分、干重热值和去灰分热值呈"V"形变动,一年中都存在两个峰值,分别在3月份和7月份或9月份;(4)灰分、干重热值和去灰分热值随林龄的增大表现为波浪形增加。由此可见,不同森林类型的细根养分和能量动态具有季节和林龄的特殊性,在进行整个地区森林生态系统物质循环和能量流动研究时,应考虑不同森林类型的特性。

木麻黄(Casuarina equisetifolia)内生真菌的分离与促生菌株的筛选

采用组织分离法从福建省大鹤林场不同年龄木麻黄各组织器官中分离与纯化得到65株内生真菌.研究木麻黄内生真菌在其器官构件内的分布规律,同时按水培和盆栽两种方式侵染无性系苗,测定接菌苗木的新梢长度,筛选出促生长的菌株.结果表明:木麻黄内生真菌主要分布于植株的鳞状叶小枝和根中,分别占筛选出菌株数量的40.0%和41.5%,且随着树龄的增大,内生真菌的数量减少;在水培苗浸泡菌液方式下的接菌处理能显著增加苗木的平均抽梢量,促进水培苗生长.其中,菌株18处理下苗木的平均抽梢量为54.85 cm,是对照苗木的7.62倍.

Effects of Lanthanum on Redox Systems in Plasma Membranes of Casuarina equisetifolia Seedlings Under Acid Rain Stress

The effects of lanthanum on some redox system(PMRS) properties of the plasma membrane(PM) vesicles from Casuarina equisetifolia seedlings under artificial acid rain(pH 4.5)stress were studied. The results show that there are NADH oxidase and EDTA Fe 3+ reductase, and nitrate reductase in the seedling PM, and they have different responses to soaking seeds for 8 h in a series of LaCl 3 solution. The NADH oxidase activities and the Nitrate reductase activities can be stimulated when La 3+ concentrations is in the range of 50～200 mg·L -1 , but their activities are inhibited or fluctuate by the higher La 3+ concentrations. The EDTA Fe 3+ reductase activities can be stimulated by La 3+ concentrations in the range of 50～400 mg·L -1 . The research also revealed that La 3+ reduces the relative permeability of membranes and have the function in protecting membranes under acid rain stress by the way of inhibiting the leakage of electrolyte.

Effects of La^(3+) on ATPase Activities of Plasma Membrane Vesicles Isolated from Casuarina Equisetifolia Seedlings under Acid Rain Stress

The effects of La^(3+) on the growth and the ATPases activities of plasma membrane(PM) vesicles isolated from Casuarina equisetifolia seedlings under artificial acid rain(pH 4.5) stress were studied. The results show that the height, length of roots, fresh weight and PM H^+-ATPase activites of Casuarina equisetifolia seedlings increase by the treatments of soaking seeds in LaCl_3 solutions with lower concentrations, and those can reach their peak values by treating with 200 mg·L^(-1) La^(3+). However, in comparison with the CK, those are inhibited by the higher La^(3+) concentrations; PM Ca^(2+)-ATPase activity is inhibited with the treatments of La^(3+). The results also reveal that the H^+-ATPase activity and the growth of cell enlarge have a remarkable positive correlation, and La^(3+) activating H^+-ATPase can facilitate plant growth. La^(3+) also can alleviate cytosolic acidification of plant under acid rain stress and indirectly maintain the stability of intracellular environment. In order to resistant to acid rain and accelerate the growth of Casuarina equisetifolia, the suitable range of La^(3+) concentrations to soak seeds for 8 h is 50～200 mg·L^(-1).

Multi-Trace Element and Rare Earth Element Composition of Coastal Casuarina Equisetifolia Ecosystem in Hainan Island,China

46 trace elements including 14 rare earth elements (REEs) in coastal Casuarina equisetifolia plant-soil system from 9 sampling sites in Hainan Island were detected by using ICP-MS. The aim is to explore the biogeochemical characteristics of migration and translocation of trace elements in soil-plant system and their function on the changes of environmental geochemistry. The results indicate that multi-trace elements in coastal sandy soil in Hainan Island are at very low level. The multi-element patterns are quite similar among plant,sandy soil and upper continental crust (UCC),and the magnitudes of trace element concentrations among them are different in the general order of plant<soil<UCC. Sandy soil has trace element concentrations with 1～2 orders of magnitudes less than those of the average UCC,while plant has 1～3 orders of magnitudes less than UCC and 1～2 orders less than the soil. The total trace element contents are not significantly different between root and needle,but significantly different between branch and root and between branch and needle. Those of root or needle are about 2 times of those of branch. Ag,Cd,In,Sn and Tl are enriched in C. equisetifolia,especially Ag.

Investigation and Analysis of Understory Vegetation in Casuarina equisetifolia Forests in Northern Hainan Province

Understory vegetation in the Casuarina equisetifolia forests at different ages was sampled and analyzed fi rstly, and then the structural features, biomass, and distribution characteristics of carbon stock of the understory vegetation, as well as the quantity and thickness of the understory litter were studied. The results show that the understory vegetation in the C. equisetifolia forests is mainly composed of herbaceous plants, and there are nearly no shrubs in the study area. Moreover, the quantity of herbaceous plants rises obviously with the increase of forest age. There is a big difference between the woodlands at different ages in total biomass of herbaceous plants, and the maximum of total biomass can be found in 15-year-old woodland, reaching 1.68 t/hm^2; the biomass of overground parts of herbaceous plants is higher than that of underground parts. There is a big difference between the woodlands at different ages in thickness of the understory litter, and the thickness of understory litter in 10-yearold woodland is the highest, reaching 6.67 cm. The maximum quantity of the understory litter has reached 14.69 t/hm^2, and the thickness of the half decomposed litter is larger than that of the undercomposed litter in most woodlands.

Seasonal variation and ecological importance of tannin and nutrient concentrations in Casuarina equisetifolia branchlets and fine roots

In this study,we investigated the effects of environmental factors on plant phenolic variability,seasonal dynamics of total phenolic content(TP),extractable condensed tannins(ECT),protein-bound condensed tannins(PBCT),fiber-bound condensed tannins(FBCT),total condensed tannins(TCT),protein precipitation capacity(PPC)and nutrient content in the branchlets and fine roots of Casuarina equisetifolia.TP and TCT concentrations in branchlets were lowest in the spring,then increased in summer and autumn,similar to the seasonal dynamics in air temperature.TP and TCT concentrations in fine roots were highest in summer,coinciding with heavy precipitation.In general,TP and TCT concentrations were higher in branchlets than in fine roots.No significant difference was found in C concentration among various seasons for either branchlets or fine roots.Branchlets had significantly higher N and P concentrations than fine roots in most seasons.The C/N and N/P ratios in branchlets were significantly lower than in fine roots in all seasons,except summer.The relationship between branchlets and fine roots was significant for C,P and FBCT,but no significant relationships were found for N,TP,ECT,PBCT and TCT.Additionally,TP and TCT content were each significantly correlated with PPC in branchlets and in fine roots.Both TP/N and TCT/N ratios were highest in the autumn for the branchlets and in the summer for fine roots.The results indicate that high temperatures lead to increased tannin production in branchlets,but that the tannin content in fine roots is mainly affected by precipitation.Tannin content was greater in branchlets than in fine roots,which may indicate that selective pressure is greater on branchlets than on fine roots.

Delonix regia and Casuarina equisetifolia as passive biomonitors and as bioaccumulators of atmospheric trace metals

The suitability of two common and ubiquitously distributed and exotic ornamental plant species in Nigeria-Delonix regia and Casuarina equisetifolia as biomonitors and as effective bioaccumulators of atmospheric trace metals （Cd, Pb, Zn and Cu） has been evaluated. Bark and leaf samples from these plant species were collected in June and July 2006 at five locations in Benin City. Four of the sampling sites were in areas of high traffic density and commercial activities, the fifth site is a remote site, selected to act as a control and also to provide background information for the metals. The plant samples were collected and processed using standard procedures and trace metals were determined using atomic absorption spectrometer. The bark of the plants was able to bioaccumulate the trace metals, especially Pb which originates from anthropogenic contributions in the city. The Pb range of 20.00-70.00 μg/g measured for the bark samples ofD. regia, exceeded the normal plant Pb concentration of 0.2-20.0 μg/g and most Pb data available in literature. The bark of the plants was observed to accumulate more metals compared to the leave, while D. regia was found to be slightly better than C. equisetifolia in trace metal uptake efficiency. Spatial variations in the distributions of Pb and Zn were significant （p 〈 0.05）, and the continuous use of leaded fuel in Nigeria was identified as the predominant source of Pb in the atmosphere.

Seasonal changes in tannin and nitrogen contents of Casuarina equisetifolia branchlets

Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT), and protein precipitation capacity (PPC) in young, mature and senescent branchlets of Casuarina equisetifolia were studied at Chishan Forestry Center of Dongshan County, Fujian Province, China. In addition, nitrogen contents of branchlets at the different developmental stages were also determined. The contents of TP and ECT, and PPC in young branchlets were significantly higher than those in mature and senescent branchlets through the season. However, PBCT contents were significantly higher in senescent branchlets than those in young and mature branchlets; FBCT fluctuated with season. Young branchlets had the highest N content, which decreased during branch maturity and senescence. The highest contents of TP and the lowest contents of TCT and N in young and mature branchlets were observed in summer. There was a significant negative correlation between TP and N contents. In contrast, TCT contents were positively correlated to N contents. Nutrient resorption during senescence and high TCT:N ratios in senescent branchlets are the important nutrient conservation strategies for C. equisetifolia.

木麻黄细根形态和化学计量特征对P添加的塑性响应

探究不同发育阶段木麻黄防护林细根形态和化学计量特征对磷(P)添加的塑性响应规律,为滨海沙地土壤低磷限制下进行木麻黄不同发育阶段有针对性的施肥抚育提供科学依据。以福建省平潭岛木麻黄幼龄林(5 a)、中龄林(12 a)和成熟林(25 a)为研究对象,以内生长土芯法开展P添加试验,细根在内生长芯生长一年后,采用功能划分法对细根形态性状和化学计量特征进行测定。结果表明:(1)P添加显著提高木麻黄细根根长和根表面积,其中,总根长和总表面积总体提高7.79倍、8.69倍,比根长和比表面积总体提升15.1%、19.5%;(2)不同根系功能类群间,细根形态对P添加的塑性响应具有较显著差异,形态塑性以吸收根为主,且吸收根对P养分资源的响应更为敏感,P添加使吸收根P含量总体提高56.0%,C/P和N/P总体降低18.7%和38.7%,组织密度总体降低31.4%;(3)对于土壤P养分资源的变化,不同林龄木麻黄采取不同的塑性响应策略,P添加后,幼龄林主要通过吸收根化学计量特征变异,改变自身生理性状获取P元素,中龄林细根形态和化学计量特征无显著变异,成熟林主要通过改变吸收根形态,扩大根系吸收面积获取P元素。外源P添加可以协调木麻黄细根形态与化学计量特征的内部关系,而不同林龄木麻黄细根在获取P资源时会选择性投资。故在木麻黄施肥抚育时,应根据不同林龄采取针对性的抚育方案。

木麻黄基干林带对台风“杜苏芮”的防风效应

为了解海防林对台风的防护效应,以惠安赤湖国有防护林场监测站收集的“杜苏芮”台风登陆前后的气象数据为材料,分析了台风登陆前后近地层的风速、风向、湍流强度、防风效能和气流加速率等的特征规律。结果表明:(1)台风登陆前后的平均风速和风向时程变化特征满足了台风眼区经过的条件,平均风速曲线呈“M”形双峰分布,通过采集到的台风眼区、眼壁和外围强风的完整风况数据,完整展示了台风经过林带前后风速、风向的演变过程。(2)湍流强度的时程整体变化趋势随着台风靠近和离去呈现增大-减小-剧增-回落的过程,尤其台风后风圈影响的区域,湍流强度剧烈增大,强度可增大2倍以上。(3)向岸风在垂直方向上,弱风或强风的防风效能随高度增加而降低,高度相同,林带后弱风的防风效能小于强风;水平方向上,林内及林带后1H和5H处防风效能最好,在高度3 m平均防风效能为49.57%~93.93%,在高度9 m平均防风效能为44.04%~90.10%。离岸风在垂直方向上,随着气流靠近林带,弱风或强风的气流加速率随高度增加而增大,林带后1H高度3 m气流加速率平均为0.2193,高度9 m气流加速率平均为0.3242,林内气流加速率达到最低值;而风越过林带后,弱风风速恢复到88%左右,强风的气流则有个加速的过程。

连栽对木麻黄人工林根际土壤古菌群落变化的影响

[目的]探究连栽对木麻黄人工林根际土壤古菌群落变化的影响,为探明木麻黄连栽障碍机制提供基础理论依据。[方法]以3个不同连栽代数(第一代First continuous plantation,FCP;第二代Second continuous plantation,SCP;第三代Third continuous plantation,TCP)的木麻黄人工林根际土壤为材料,以未种植木麻黄的天然乔木林根际土壤作为对照(CK),通过Illumina NovaSeq测序平台对古菌群落进行高通量测序。[结果]从3个不同连栽代数木麻黄人工林根际土壤和对照土壤中总共得到1 146 390条有效序列,以100%序列相似度聚类得到998 515个ASV。Alpha多样性分析结果表明,所观察到的物种数和Chao1指数均随着连栽代数的增加呈现下降的趋势,而Shannon指数、Simpson指数和pielou_e均以FCP最高,TCP次之,SCP最低。Beta多样性分析、PCoA分析、UPGMA聚类分析和Anosim分析结果表明,不同连栽代数木麻黄根际土壤古菌群落物种多样性存在差异,但不同组间差异不显著。共检测到5个门,优势菌门为奇古菌门(Thaumarchaeota),且奇古菌门占比随着栽植代数的增加呈现下降的趋势,与对照相比,FCP、SCP、TCP分别下降了17.42%、50.97%、51.51%。古菌群落与土壤理化性质相关性分析结果显示,奇古菌门与pH、全钾(TK)、全氮(TN)、全磷(TP)呈显著正相关,泉古菌门与速效磷(AP)和速效氮(AN)呈显著正相关,不同古菌群落与土壤理化因子之间的相关性存在显著差异。[结论]本研究证实了木麻黄人工林经过多代连续栽植后,根际土壤古菌群落结构发生显著变化,推测古菌群落结构失衡是导致土壤微生态失衡的重要原因之一。研究结果为揭示木麻黄人工林连栽障碍形成的原因提供了理论依据。

沿海风口木麻黄基干林带防风效能研究

福建省沙地木麻黄基干防护林带是沿海地区抵御风沙的生态屏障,在改善沿海地区的生态环境中发挥了重要作用。通过建立的生态定位监测站,利用长期观测的年序列数据针对沿海风口木麻黄基干林带不同季节、风向的防风效能进行统计分析,结果表明:春季、秋季和冬季主风向以NNE、NE和ENE为主,夏季以SSW、SW为主,主风向上风速等级高频率也大。主风向在不同季节垂直方向上,随着高度增加,风速增加,防风效能降低;林带内垂直于林带的风向,防风效能最小,而随着角度的减少,防风效能逐渐增大;水平方向上,林带后1 H防风效能最大,垂直于林带的风向防风效能最大,随着角度的减少,防风效能逐渐减小,林带后5~20 H随着距离的增加防风效能下降,但趋势变缓。

短枝木麻黄家系对青枯病的抗性评价与选择

为探讨短枝木麻黄(Casuarina equisetifolia)对青枯病(Ralstonia solanacearum)侵染后的生理生化响应,利用其生理生化响应指标与抗病性特征的相关性开展短枝木麻黄家系的抗病评价和选择。结果表明,26个短枝木麻黄家系褐梗小枝接种青枯病后,病情指数(DI)和相对病害强度(RDI)均存在极显著差异(P<0.01)。在接种青枯病后,家系间的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、总酚(TP)和类黄酮(Flav)差异均达显著或极显著水平,说明参试家系对青枯病抗性的变异丰富,具有较大的选择潜力。短枝木麻黄家系的病情症状与6个生理生化指标间均呈显著或极显著的负相关关系,说明青枯病侵染后防御酶活性或次生代谢物含量越高,木麻黄的病害程度越低。利用2个病情特征性状和6个生理生化指标对短枝木麻黄不同家系进行综合评价和选择,按照30%的入选率初步选出201、206、198、207、202、213、208和195号等8个抗病家系。这些抗病家系的RDI和DI比总体均值分别低25.94%和28.93%,SOD、CAT、PAL、PPO、TP和Flav比总体均值分别高11.90%、13.50%、24.77%、12.71%、25.68%和18.76%。筛选出的8个家系的病害程度低,萎蔫枝条少,植株生长基本不受影响,表明抗病性较强,可以在后续生产中广泛使用。

盐磷胁迫对木麻黄和台湾相思种子萌发及幼苗生长的影响

恶劣环境下,人工海防林因面临养分胁迫而经营困难。为探讨盐、磷胁迫对主要海防林树种木麻黄和台湾相思种子萌发及生长的影响,该研究分别用不同浓度的NaCl(盐)和KH_(2)PO_(4)(磷)溶液处理种子和浇灌幼苗,测定种子萌发和幼苗生长指标。结果表明:(1)高盐胁迫显著抑制种子萌发,对幼苗生长有一定影响,但两种植物影响程度不同;台湾相思种子萌发耐盐性高于木麻黄,前者相对盐害率最大值为23.03%,后者为89.15%;随着盐浓度增加,木麻黄和台湾相思种子的发芽率、发芽势、发芽指数和活力指数均降低,对应最大值分别为38.70%、34.67%、18.70、0.055和76.67%、62.22%、48.46、6.11。(2)两种植物的株高和根长随盐浓度增加而降低,木麻黄和台湾相思株高分别为12.29~6.01 mm和48.27~17.33 mm,根长分别为8.57~1.45 mm和33.41~5.88 mm;台湾相思根、茎、叶生物量及根冠比均随盐浓度的增加逐渐减小,木麻黄各处理差异较小。(3)台湾相思的种子和幼苗较木麻黄更耐低磷环境,二者最适磷浓度存在差异;木麻黄种子发芽率(49.33%)、发芽指数(23.12%)、活力指数(0.093)及根茎叶生物量最大值均在0.1 mmol·L^(-1)磷处理;台湾相思种子发芽率(81.11%)、发芽势(62.22%)、发芽指数(38.23)、活力指数(5.07)、株高(54.48 mm)及根长(37.16 mm)最大值均在5 mmol·L^(-1)磷处理,10 mmol·L^(-1)磷处理抑制其萌发。因此,播种海防林种子或种植幼苗时须根据土壤盐和磷的含量选择播种或种植方式。

短枝木麻黄半同胞家系苗期遗传变异及选择

为探究短枝木麻黄半同胞家系苗期生长与分枝性状遗传变异规律,初步筛选优良种质,以40个短枝木麻黄半同胞家系1年生幼苗为材料,对其苗高、地径、干重、根冠比、侧枝数、侧枝角和侧枝长等7个性状进行遗传分析;通过聚类分析和布雷金多性状综合评价法,进行优良家系选择。结果表明,短枝木麻黄半同胞家系苗期生长与分枝性状变异丰富,7个性状在家系间差异均达到极显著水平;各性状家系遗传力变化范围为0.36~0.83,受中度或强度遗传控制。以10%入选率,选出4个优良家系,分别为3-265、5-373、1-266和2-343家系,入选家系苗高、地径、干重、侧枝数和侧枝长的现实增益分别为21.14%、19.10%、41.83%、19.97%和18.88%,遗传增益分别是17.55%、15.66%、29.70%、15.57%和15.10%,选择效果较为显著。短枝木麻黄幼苗在家系间具有很大的选育潜能,本研究选择出的优良家系既丰富了短枝木麻黄优良种质资源,也为后续短枝木麻黄遗传改良和林分营建提供了较好的种质材料。

木麻黄NHX基因家族的鉴定及盐胁迫下的表达分析

Na^(+)/H^(+)转运蛋白在植物的耐盐性和生长发育中起关键作用。该研究采用生物信息学方法对木麻黄(Casuarina equisetifolia L.)NHX基因家族成员进行全基因组鉴定和分析,并利用qRT-PCR技术检测NHX基因在盐胁迫下的表达,以探讨木麻黄NHX家族基因的生物学功能,为进一步研究盐胁迫机制以及挖掘其抗逆基因奠定理论基础。结果显示:(1)鉴定获得8个木麻黄NHX基因家族成员(CeqNHX1-8),系统进化树分析发现其可分为Endo、Vac和PM共3个亚家族,分别包含1、5和2个基因;编码氨基酸数为324~546个,分子量为34.87~60.27 kD,等电点在6.29~9.08之间,均为疏水蛋白。(2)基因结构和Motif分析发现,所有CeqNHXs基因的外显子数为2~17不等,且均具有保守的Na^(+)/H^(+)交换结构域;CeqNHX基因的蛋白质二级结构主要以α-螺旋和不规则卷曲为主。(3)木麻黄CeqNHX基因的启动子区含有大量非生物胁迫和激素响应元件,其中CeqNHX5启动子共含有13种共38个元件。(4)qRT-PCR分析表明,CeqNHX基因家族成员在木麻黄根、茎、枝和雄花序中均有不同程度的表达,且多数主要在小枝上表达;在200 mmol/L NaCl处理下,8个木麻黄CeqNHXs基因的表达量均有一定程度的上调。研究表明,木麻黄CeqNHXs基因家族可能参与多种激素和应激反应的调节,且CeqNHXs基因的表达对盐胁迫有显著的响应,推测CeqNHXs基因与木麻黄的耐盐性相关。

木麻黄和台湾相思苗木混植对生长和营养含量的影响

为探究种间竞争对木麻黄和台湾相思生长的影响,利用相邻混植和独立盆栽试验测定木麻黄和台湾相思生长和养分含量的变化,分析两者的种间竞争差异。结果表明,混植对木麻黄树高和根冠比影响显著(P<0.05),但对地径无显著影响(P>0.05)。与单植栽培方式相比,混植栽培方式下木麻黄树高和地上生物量分别增加57.28%、20.92%,而根总长、根总表面积以及根总体积分别减少62.67%、51.25%和285.19%;混植对台湾相思树高影响显著(P<0.01),对其地径、根冠比无显著影响(P>0.05);在混植栽培方式下,台湾相思树高、地径、总生物量、根总长、根总表面积以及根总体积分别减少119.17%、17.72%、35.75%、11.15%、33.79%和44.62%。根系在磷信号刺激下,仅有台湾相思L4和SA4径级增加;木麻黄叶中Na含量降低81.63%,而P元素和K元素分别增加11.38%、12.30%,根中Na、P、K元素含量分别减少26.17%、28.29%和21.45%。台湾相思叶中Na、K元素含量分别降低6.23%、7.78%,P元素增加7.55%,根中Na、P、K元素含量分别增加24.81%、22.05%、24.53%。木麻黄和台湾相思在混植栽培方式下,均通过改变自身形态或营养成分抑制对方,说明邻株竞争可以改变沿海人工林中植物的适应性和群落结构,也表明植物根系在邻株竞争中存在重要作用。因此,研究结果可为沿海防护林的更新恢复和经营管理提供理论指导。

木麻黄根乙酸乙酯部位化学成分研究

为阐明木麻黄(Casuarina equisetifolia)的化学成分,采用有机溶剂提取、萃取及多种分离技术,从其根中分离得到14个化合物。经光波谱分析,其结构分别鉴定为5-hydroxy-3-methoxyphenyl-6-O-syringoyl-β-D-glucopyranoside (1),高良姜苷A(2), heterophylloside C (3)、6’-O-vanilloylisotachioside (4)、3,4,5-trimethoxyphenyl-6-O-syringoyl-β-D-glucopyranoside (5)、香草醛(6)、丁香醛(7)、3,4-二羟基苯甲醛(8)、齐墩果酸(9)、桦木酸(10)、胡萝卜苷(11)、胡萝卜苷亚油酸酯(12)、(±)-lyoniresinol2-O-α-rhamnoside (13)和(-)-9-acetyl-isolariciresinol 9’-O-α-L-rhamnopyranoside (14),其中化合物14为新的木脂素。

盐胁迫下施氮对木麻黄幼苗生长生理的影响

本试验以木麻黄幼苗为试验材料,采用水培法以NH4NO3作为氮肥,分析了盐胁迫下不同浓度施氮处理木麻黄幼苗生长生理指标的变化。结果表明:与无盐害正常生长的对照处理相比,在2~10 g·L^(-1)NaCl处理下幼苗遭受了不同程度盐害,盐害率为4.3%~100%,耐盐阈值6 g·L^(-1)。在6 g·L^(-1)NaCl处理下,添加0.25~1 g·L^(1)NH_(4)NO_(3)显著降低了幼苗盐害率,其中以0.75 g·L1NH4NO3处理下盐害率最低,较未施氮处理降低了52.3%。NH4NO3明显降低了叶片中Na+浓度,而Cl-浓度变化趋势不明显,同时叶片净光合速率(Pn)、水分利用效率(WUE)、胞间二氧化碳浓度(Ci)增大,蒸腾速率(Tr)、气孔导度(Gs)减小,相对电导率和丙二醛(MDA)含量下降。整体上,以0.75 g·L^(1)NH_(4)NO_(3)处理下幼苗生长生理指标表现最佳。研究表明,施用NH_(4)NO_(3)能有效缓解木麻黄幼苗受到的盐害程度,但存在剂效性,其使用量需控制在适量范围。