不同基质材料对油茶容器苗生长生物量及养分含量的影响

研究不同基质材料对油茶容器苗的影响,寻找可以部分替代泥炭土的本土基质材料。在不同处理育苗条件下,测定1年生油茶容器苗的成活率、生长量、生物量、叶绿素含量和地上部分营养元素含量,并分析基质与地上部分营养元素含量的相关性。试验结果发现：成活率、苗高、地径、高径比、主根长、主根/侧根鲜重、地上/地下生物量、茎根比/FW、茎根比/DW、叶绿素含量等指标以处理Ⅰ（50%泥炭土+50%其余相同成分）与处理Ⅴ（5%食用菌下脚料+5%鸡粪+5%牛粪+35%泥炭土+50%其余相同成分）表现最优,且两者均与其他3个处理差异显著;各处理间氮、磷、钾、钙、硫、铁、锰、铜、锌元素含量差异显著,但镁、硼元素含量差异不明显。相关性分析表明,镁元素与速效钾、有机质呈显著的正相关,而其他元素为负相关。综上所得,处理Ⅴ在用本土基质来替代部分泥炭土的结果最好。本研究为降低油茶基质育苗成本和维持基质的可持续利用提供一条新的途径。     

橡胶树大筒苗培育方法VII.遮阴率的筛选

为了解不同遮阴环境下橡胶树(Heveabrasiliensis)大筒苗的生长及光合特性,明确大筒苗生长的适宜光照环境,以小苗芽接苗和组培苗为胚苗的橡胶树大筒苗为材料,设置5个遮阴处理：CK (全光照),S60、S70、S80和S90 (分别为60%、70%、80%、90%遮阴率),观测其出圃时的生长指标和光合参数变化情况。结果表明,不同遮阴率对橡胶树大筒苗的生长、光合参数及出圃时顶蓬叶的叶面积和叶绿素相对含量均有极显著影响,且2种胚苗间差异显著。大筒苗的壮苗指数随遮阴率的增加呈现先增后降的趋势;与全光照相比,遮阴显著影响大筒苗的出圃率,但对定植成活率的影响较小;胚苗类型与遮阴处理的交互作用明显。全光照和过度遮阴(S90)均会明显抑制大筒苗的生长,不同胚苗的大筒苗最适遮阴率不同,小苗芽接苗大筒苗在S60、组培大筒苗在S80下的生长表现最好。因此,橡胶树大筒苗培育时应根据不同的胚苗类型选择适宜的遮阴措施。     

不同栽培措施对凤丹容器苗生长及生理的影响

分别采用不同基质配比(即泥炭和珍珠岩体积比分别为1：0、2：1和3：1)、不同促侧根措施(包括主根截短和200 mg·L-1 IBA溶液灌根单一措施以及上述2种单一措施的复合措施)和不同栽培容器(包括穴盘、营养钵和无纺布育苗袋)对凤丹( Paeonia ostii T. Hong et J. X. Zhang)容器苗进行培育,分析了容器苗的形态指标、单株质量、根冠比及部分生理指标的差异,并在此基础上筛选出适宜凤丹容器苗培育的栽培措施。分析结果表明：在泥炭-珍珠岩(体积比3：1)混合基质中,凤丹容器苗的单株侧根数、单株地下部鲜质量和干质量、根冠比以及叶片的总叶绿素含量、可溶性糖含量和含水量均显著高于其他基质。采取主根截短单一措施或复合措施后,容器苗的单株叶面积、单株侧根数、单株地下部鲜质量和干质量、根冠比及叶片含水量均显著高于对照(不做任何处理)和采取200 mg·L-1 IBA溶液灌根单一措施的容器苗,其中,采取复合措施的容器苗大部分指标最高。在无纺布育苗袋和营养钵中栽培的容器苗的株高、根颈直径、单株侧根数以及叶片的总叶绿素含量、可溶性糖含量和含水量显著高于在穴盘中栽培的容器苗;其中,在无纺布育苗袋中栽培的容器苗的单株侧根数以及叶片的总叶绿素含量和含水量均最高,且这3个指标显著高于在营养钵中栽培的容器苗。研究结果显示：不同栽培措施对凤丹容器苗的生长及生理均有一定影响,总体上看,对根系的单株侧根数、主根长、地下部质量和根冠比以及叶片的叶面积、总叶绿素含量、可溶性糖含量和含水量的影响均较大。根据实验结果,初步筛选出适宜凤丹容器苗培育的栽培措施,即用无纺布育苗袋,以泥炭-珍珠岩(体积比3：1)混合基质为栽培基质,实施主根截短和200 mg·L-1 IBA溶液灌根复合措施。     

伊贝母种子萌发和籽苗建立

在子叶出土萌发的植物类型中,伊贝母种子萌发过程是罕见的。萌发初期,子叶优先生长。首先伸长而突破种皮,接着长出地面,此后,胚根才开始生长并产生不定根。种子萌发后形成特殊籽苗。在地上部分,子叶变绿,成为第一生长季唯一的同化叶;在地下部分,上胚轴扁平化,芽鳞肉质化,于是形成小鳞茎。籽苗形态属于最简化的类型。伊贝母的籽苗与其营养更新苗相比,是很弱小的。     

青刺果播种育苗技术的初步研究

采用随机区组设计了青刺果不同播种时间和不同播种方法试验,进行青刺果不同育苗方式对比研究。结果表明:青刺果的育苗宜随采随播,其种子出苗率达72.4%,随着种子储藏时间的后移,出苗率显著下降,干藏与沙藏对种子出苗率的影响差异不明显;裸根苗和容器苗苗木生长质量上无明显差别,随采随播到当年雨季造林时(9月)苗木嫩小,不宜上山造林,但容器苗此时可造林。     

蘑菇渣堆肥对华北落叶松移植容器苗生长和营养积累的影响

为缓解草炭大量使用带来的环境问题,在华北落叶松容器育苗过程中添加蘑菇渣堆肥以替代草炭,添加蘑菇渣堆肥体积比例分别为0%(T₀)、15%(T₁)、18.75%(T₂)、25%(T₃)、37.50%(T₄)、50%(T₅)、56.25%(T₆)、60%(T₇),研究不同配比下基质的理化性质以及对华北落叶松1年生移植容器苗生长和营养积累的影响.结果表明: 当蘑菇渣堆肥替代草炭的比例≤50%时,苗木苗高、地径和生物量与常用草炭处理无显著差异,且处理T₂、T₄、T₅苗木体内养分浓度显著高于对照,基质pH值处于微酸性或中性范围,适宜苗木生长;当蘑菇渣添加比例＞50%时,基质pH值偏碱性,苗木生长受到不利影响,苗木质量下降.当蘑菇渣添加比例为15%时,苗木质量最好,苗高、地径和单株生物量达到最大.因此,蘑菇渣替代草炭培育华北落叶松移植容器苗是完全可行的,替代比例最高可达到50%,当添加比例为15%时,可培育出高质量的苗木.     

重金属对黄瓜籽苗发育影响的研究

选用黄瓜(Cucumis sativus)籽苗为材料,硫酸铜、醋酸铅、硫酸锌、氯化镉和氯化镍为化学处理试剂,研究它们对黄瓜籽苗的生长及其根尖细胞有丝分裂的影响。发现随着化学处理试剂浓度的增大,黄瓜籽苗根长度、苗高度、侧根数和最长侧根的长度均有所下降,其中下降最明显的是根长度。同样,根尖细胞有丝分裂的细胞数量明显减少,细胞分裂速率减慢。5种重金属盐中,硫酸铜的毒性最甚,氯化镉,醋酸铅次之。     

不同栽培基质对浙江楠和闽楠容器苗生长和根系发育的影响

按体积比5∶5、6∶4、7∶3和8∶2分别将泥炭与珍珠岩、谷壳、树皮粉和香菇废料混合制成16种栽培基质,研究了不同基质组成和配比对浙江楠(Phoebe chekiangensisC.B.Shang)和闽楠[P.bournei (Hemsl.) Yang]容器苗生长状况(包括苗高、地径、总干质量和根冠比4个指标)以及根系发育状况(包括根总长、根表面积和根体积3个指标)的影响.结果表明:采用不同基质,浙江楠和闽楠容器苗的各项指标间均有差异,其中部分指标有显著差异.从基质组成看,使用泥炭-珍珠岩、泥炭-谷壳和泥炭-树皮粉3类基质,浙江楠和闽楠容器苗的生长和根系发育的各项指标均优于使用泥炭-香菇废料基质,表明前3种基质组成更有利于浙江楠和闽楠容器苗的生长和根系发育.从基质配比看,当基质中泥炭体积分数达到70％时,浙江楠和闽楠容器苗的苗高和地径最大;而当基质中泥炭体积分数达到50％时,其根总长、根表面积和根体积较大;但基质中泥炭比例对容器苗总干质量的影响无明显规律.除闽楠容器苗的地径外,基质组成与基质配比的交互作用对浙江楠和闽楠容器苗的生长和根系发育指标均有显著影响.综合分析结果表明:选用泥炭-谷壳或泥炭-树皮粉基质,按体积比7∶3配制,适用于浙江楠容器苗的培育;按体积比8∶2配制,适用于闽楠容器苗的培育.     

育苗基质对米老排容器苗生长及叶绿素荧光特性的影响

为筛选米老排容器苗生长的最佳基质配方,研究了黄心土和轻基质不同配比对容器苗生长和叶绿素荧光特性的影响。结果表明,米老排苗高、地径和总生物量随轻基质比例的增加呈先增加后降低的趋势,且以T5处理(黄心土∶轻基质=5∶5)达最大值,分别是对照的3.60、1.97和13.5倍。除主根长外,各处理的根系指标均大于对照。随轻基质比例的增加,米老排幼苗总根长、总根表面积、总根体积等均表现为先增加后减少的趋势,以T5处理达到峰值;而根系平均直径则随轻基质的增加呈增大的趋势。T5处理的初始荧光Fo最小、最大荧光Fm和PSII最大光化学效率(Fv/Fm)最大,其光化学能力最强。因此,米老排容器苗在黄心土∶轻基质=5∶5中生长最优,建议推广轻基质比例为50%~60%的混合基质作为米老排容器育苗基质。     

不同培育时间侧柏种基盘苗根系生长和分布

以3月直接在培养池中播种培育的侧柏种基盘苗作对照,将同期播种的侧柏种基盘苗进行悬空培养,于6月、8月和10月分别移栽到培育池(分别称为种基盘苗、6月移栽苗、8月移栽苗、10月移栽苗),并于翌年3月挖根,研究不同培育时间对移栽后侧柏幼苗根系生长和分布的影响。结果表明:苗木株高、根分布最大深度、根和地上部干重由大到小依次为:6月移栽苗>8月移栽苗>种基盘苗>10月移栽苗。根冠比由大到小依次为6月移栽苗>8月移栽苗>10月移栽苗>种基盘苗,但除了种基盘苗与6月移栽苗之间差异性显著外,其它处理之间差异性不显著。随着悬空培育时间的延长,空气断根限制了侧柏主根的生长,促进了侧根生长,降低了主侧根长度比。但经悬空培育后,任何处理的移栽苗都没有发生根系盘绕现象,移栽后主根的再生没有受到影响。     

疏花水柏枝幼苗生物量与构件对模拟土壤地下水位变化的响应

通过模拟不同地下水位的方法,对疏花水柏枝（Myricaria laxiflora（Franch.）P.Y.Zhang et Y.J.Zhang）一年生幼苗在不同条件下地上与地下部生物量及构件的变化进行测定,分析幼苗生长对地下水位变化的响应。结果显示：随着地下水位的降低,疏花水柏枝幼苗的生长特征指标均呈先增加后减少的趋势,其中地上、地下部分生物量的最高值分别为0.0438、0.0100 g,最低值分别为0.0177、0.0026 g。幼苗地上部生物量在-10 cm处理水平最高;地下部生物量在-15 cm处理水平最高。幼苗直径、根表面积、株高、主根长度、根体积、一级枝数、二级枝数等指标也分别在-10 cm或-15 cm处理水平达到最高值。疏花水柏枝幼苗主要构件的生长与地下水位的变化存在显著相关性。主成分分析结果表明,幼苗的地下部分更容易受到土壤地下水位变化的影响,幼苗性状症候群随地下水位的变化而发生移动,说明该物种幼苗在不同地下水位时的生长投资策略具有较大差异。     

Secondary embryonary root associated with seed germination in Garcinia intermedia (Clusiaceae) and its possible role in seedling survival

Germination tests on Garcinia intermedia (Clusiaceae) seeds showed the growth of two types of roots: additionally to the primary root, a secondary root crosses the seed lengthwise. To determine its possible role on the survival and growth of this species, 90 seedlings at least six months old (collected in Central Costa Rica) were planted in plastic bags with organic soil, and placed in a greenhouse. The seedlings were treated as follows: treatments in which the primary or secondary root was cut off, and a control group with both roots intact (30 replicates each). After three months 10 seedlings/month/treatment were extracted to measure their height, basal diameter, root length (main and secondary root), and biomass of the stem, roots and seed (without its coat). Control seedlings had the highest growth, followed by those without secondary roots. Nonetheless, more than 90% of the seedlings whose primary roots were cut off, survived after five months of the excision treatment, in part due to the capacity of this species to regenerate its radical system through the seed reserves, sprouting of a primary-like root, and/or the growth stimulus of the secondary root (60% of the total: 20% with sprouts from the primary root stump, 13.3% with a growth stimulus of the secondary root, and 26.7% with both conditions). The length of the sprouted roots was significantly different only on those plants that were extracted during the first two monthly measurements, when compared with the control (F6 = 18.6, F7 = 16.0, p < 0.01).     

不同培育方式对橡胶树实生苗生理指标、养分及长势的影响

橡胶树(Heveabrasiliensis)种子催芽生长一般使用沙床培育,沙子是不可再生资源,为了选择一种适合橡胶树种子培育方式来替代对沙子的依赖,该研究通过水培、悬空培育和传统的沙培比较橡胶树实生苗第1蓬叶稳定时,苗木的生长势、生理指标及养分含量。结果表明,水培实生苗地上部株高、茎粗、叶面积的长势最佳,壮苗指数和生物量的含量最高,但其根太长,根相对较细。水培的叶、茎、根的可溶性糖、丙二醛、游离脯氨酸、超氧化物歧化酶的含量均较低;水培和悬空培育的叶片和茎的叶绿素、类胡萝卜素及根系活力的含量没有显著性差异,均高于沙培。水培的叶、茎、根中的氮和磷含量最低,沙培的最高;而水培实生苗根和茎中钾的含量较高,叶片中含量与悬空培育、沙培均没有显著性差异;悬空培育在叶、茎、根中钾的含量最低。水培促进了苗木的生长,降低干旱胁迫,提高养分利用率,但后续还需调控根系,建设良好根团。悬空培育的苗木长势较弱,还需进一步完善方法。     

Root growth dynamics of Aleppo pine (Pinus halepensis Mill.) seedlings in relation to shoot elongation, plant size and tissue nitrogen concentration

Large and high nitrogen (N) concentration seedlings frequently have higher survival and growth in Mediterranean forest plantations than seedlings with the opposite traits, which has been linked to the production of deeper and larger root systems in the former type of seedlings. This study assessed the influence of seedling size and N concentration on root growth dynamics and its relation to shoot elongation in Aleppo pine (Pinus halepensis Mill.) seedlings. We cultivated seedlings that differed in size and tissue N concentration that were subsequently transplanted into transparent methacrylate tubes in the field. The number of roots, root depth, and the root and shoot elongation rate (length increase per unit time) were periodically measured for 10 weeks. At the end of the study, we also measured the twig water potential (ψ) and the mass of plant organs. New root mass at the end of the study increased with seedling size, which was linked to the production of a greater number of new roots of lower specific length rather than to higher elongation rate of individual roots. Neither plant size nor N concentration affected root depth. New root mass per leaf mass unit, shoot elongation rate, and pre-dawn ψ were reduced with reduction in seedling size, while mid-day ψ and the root relative growth rate were not affected by seedling size. N concentration had an additive effect on plant size on root growth but its overall effect was less important than seedling size. Shoot and roots had an antagonistic elongation pattern through time in small seedlings, indicating that the growth of both organs depressed each other and that they competed for the same resources. Antagonism between shoot and root elongation decreased with plant size, disappearing in large and medium seedlings, and it was independent of seedling N concentration. We conclude that root and shoot growth but not rooting depth increased with plant size and tissue N concentration in Aleppo pine seedlings. Since production of new roots is critical for the establishment of planted seedlings, higher absolute root growth in large seedlings may increase their transplanting performance relative to small seedlings. The lack of antagonism between root and shoot growth in large seedlings suggests that these plants can provide resources to sustain simultaneous growth of both organs.     

Comparison between clonal and sexual plantlets of Detarium microcarpum Guill. & Perr., a savanna tree species in Burkina Faso

An understanding of the proportion of true seedlings, seedling sprouts and root suckers in the forest is essential for directing the genetic composition of the future crop. We conducted a study to determine the difference between these plantlets of Detarium microcarpum based on morphological characters and carbohydrate contents in leaves and roots. For individuals ≤50 cm in height, root suckers had the highest values for height, stem length, internode number, root diameter, rachis length and leaflet number. The concentrations of starch and total nonstructural carbohydrates in the roots of seedling sprouts were superior. Plantlets did not differ in the concentration of leaf carbohydrates. For individuals >50 cm in height, root suckers had larger values for stem length, root diameter, leaflet length and width. Roots of seedling sprouts showed higher concentrations of soluble sugars and total soluble sugars. True seedlings were distinguished from seedling sprouts and root suckers using all morphological traits except collar diameter and leaflet number. Root suckers and seedling sprouts showed a closer morphological resemblance; thus resulted in slightly more than 50% discrimination success. In conclusion, discrimination between seedling sprouts and root suckers appeared to be more difficult than between true seedlings and clonal plantlets.     

Effects of Manganese Toxicity on the Growth and Gene Expression at the Seedling Stage of Soybean

In order to investigate the effects of Manganese (Mn) toxicity stress on the growth and gene expression at the seedling stage of soybean, soybean seedlings were treated with normal Mn concentration (5 μmol/L MnSO₄) and excess Mn concentration (100 μmol/L MnSO₄) by the method of hydroponic culture in this study. When soybean was subjected to Mn toxicity stress, excessive Mn could affect seedling growth, root development, the number of Mn oxide spots in leaves, and the Mn accumulation content in different parts of soybean. With the increase of exogenous Mn concentration and the prolongation of culture time, the shoot and root biomasses of soybean decreased significantly, but the plant height of soybean had no obvious effects. The total root length, root surface area and root volume of soybean decreased significantly, but the taproot length, taproot tip length and root diameter did not change significantly. The number of Mn spots in the primary leaves (first leaf) was significantly more than that in the old leaves (second leaf) and the youngest leaves (fourth leaf). The Mn concentration in leaves was significantly higher than that in roots, and the Mn concentration in the old leaves was significantly higher than that in youngest leaves with the method of inductively coupled plasma atomic emission spectrometry (ICP-AES). Moreover, the results in the present study suggested that the 10 selected genes were significantly up-regulated or down-regulated by Mn toxicity in the old and young leaves by quantitative real-time PCR (qRT-PCR) analysis. This indicates that these genes might be important in the process of regulation in old and young leaves of the physiological responses and ion transporting to Mn toxicity stress.     

辽东栎幼苗根系形态特征对环境梯度的响应

以辽东栎(Quercus liaotungensis)在陕西不同分布区:秦岭北坡(太白)、黄土高原南部(黄龙)和黄土高原中部(延安)为研究地点并设置样地,对1—5年生辽东栎幼苗的根系形态指标进行测定,分析辽东栎幼苗根系形态特征及其与环境因子的关系。结果表明:由秦岭北坡到黄土高原中部,黄龙地区辽东栎幼苗根系在发育前期(1—2年)低于太白和延安,总体上黄龙地区幼苗根系总长度、表面积、总体积、根尖数、平均直径、组织密度和单株生物量高于太白和延安地区。在太白地区,辽东栎幼苗根系表面积、总体积和平均直径较小,根系分岔数较大,幼苗根系主要通过提高分岔数来拓展自己的营养空间以适应环境;在黄龙和延安地区,幼苗根系表面积、总体积和平均直径较大,根系分岔数较小,幼苗根系主要是通过根系的伸长生长适应胁迫环境。3个地区辽东栎幼苗根系总长度、表面积、总体积、根尖数和分岔数随年龄的增长呈线性函数变化格局,均可用线性函数方程y=ax+b(a0,P0.05)进行描述。冗余分析表明幼苗根系分岔数、总长度、比根长和根尖数与土壤速效磷、硝态氮、速效钾、降雨量、石砾含量和速效氮呈正相关;与较高的土壤pH值、年均温和夏季气温呈负相关。未来辽东栎林抚育经营中,含石砾的湿润土壤生境更有利于辽东栎幼苗根系生长。     

连作草莓根系分泌物自毒作用的模拟研究

 草莓（Fragaria ananassa）根系分泌物的自毒作用是草莓连作病害发生机理研究的重要内容之一。应用组织培养技术提取草莓根系分泌物,并对其自毒作用进行了测定。结果表明,在含有根系分泌物的生根培养基中定植的草莓组培苗,其生根、根系生长均受到不同程度的抑制,生物量显著下降,而且根系分泌物对草莓幼苗根系生理活性具有抑制作用。主要表现为根系TTC还原活性下降、相对电导率增大、SOD酶活性降低及MDA生成量增多等方面,并导致草莓幼苗生长发育不良、病害加重。说明草莓根系分泌物具有自毒作用,连作条件下田间根系分泌物逐年积累后产生的自毒作用,可能是草莓再植病害发生的重要原因。