栲树不同生长发育阶段的枝系特征分析

对浙江天童国家森林公园内常绿阔叶优势树种栲树(Castanopsis fargesii)不同发育阶段植冠内的分枝式样特征进行了统计分析。结果表明：栲树在不同发育阶段的总体分枝率和逐步分枝率有显著变化,幼苗和幼树阶段的分枝率较低,而成株阶段的分枝率较高;幼树阶段的枝条长度、枝倾角和叶倾角明显大于幼苗和成株阶段,表现为明显的高生长对策;叶片配置在不同枝系上有较大差异,叶片主要集中于植冠内一级枝和二级枝上;叶片的大小从幼苗、幼树到成株阶段逐渐增大。研究结果表明栲树在生活史的不同生长发育阶段,分枝式样表现出一定的可塑性,反映了不同的适应对策。     

东灵山不同林型五角枫叶性状异速生长关系随发育阶段的变化

分析植物叶片性状种内水平的异速生长关系有助于加深理解生长发育过程中叶片的资源利用模式.分析了东灵山3个主要林型(白桦林、胡桃楸林、辽东栎林)中五角枫成树、幼树、幼苗的叶面积、叶体积、叶含水量与叶干重之间的异速生长关系.结果表明:成树叶面积增长速度小于叶干重的增长速度,幼树、幼苗叶面积与叶干重保持同速增长;成树、幼树叶干重与叶体积保持同速增长,幼苗叶体积的增长速度超过了干重的增长速度;成树叶含水量的增长速度小于叶干重的增长速度,幼树、幼苗两性状间保持等速增长.叶含水量与叶干重的异速生长指数在不同的林型间有显著差异,白桦林叶含水量的增长速度小于叶干重的增长速度,其余两个林型均为等速增长趋势.这些结果揭示了不同发育阶段五角枫资源利用方式的转变.随叶干重的增加,成树将更多的叶生物量投资于同化和支持结构;幼树则保持对光合面积和光合同化结构的稳步投资;而幼苗主要投资于叶面积的增大.叶含水量与叶干重的异速曲线在不同林型间的差异说明叶片代谢活性相较于其他叶性状可塑性更高.     

干旱胁迫和化感作用对榄仁树幼苗生长、光合作用及生理生化的影响

该研究通过榄仁树幼苗的盆栽实验,用称重控水法设置3个水平的土壤水分含量(分别占田间持水量的75％~80％、50％~55％、30％~35％)和2个浓度水平的木麻黄凋落物浸提液,研究不同土壤干旱程度及不同浓度木麻黄凋落物浸提液对榄仁树生长、光合作用及生理生化的影响。结果表明：随着幼苗生长期的延长,土壤干旱和木麻黄凋落物浸提液对榄仁树幼苗存活率和株高增长有一定影响。60 d胁迫后显著减小了幼苗叶片数、叶面积、叶片含水量及叶片的生物量。15~60 d期间幼苗的净光合速率( Pn)、气孔导度( Ccond)、蒸腾速率( Tr)均显著减小,而幼苗叶片胞间CO2浓度( Ci)呈先减后增的变化。幼苗的水分利用率( WUE)和气孔限制值( Ls)显著增加,是导致光合作用降低的主要原因。干旱和木麻黄凋落物浸提液能显著增加榄仁树幼苗的叶片和根的细胞膜透性、Peroxidase(POD)活性及叶片Superoxide dismutase(SOD)活性。二元方差分析表明,土壤干旱和木麻黄凋落物浸提液对榄仁树的生长、光合作用及生理生化的影响有明显的交互作用且表现出一定的拮抗作用。该研究结果可为构建混交林型海防林提供参考。     

低温胁迫对柳杉不同无性系的影响及抗寒性评价

通过分析柳杉不同无性系抗寒性的差异,评价柳杉不同无性系抗寒能力,为柳杉的引种栽培及抗寒育种提供理论依据。以生长一致的10个柳杉无性系的2年生枝条为试验材料,分别在4℃、0℃、-4℃、-8℃、-12℃、-16℃和-20℃目标低温下处理12 h,对其叶片的丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性及叶绿素荧光参数进行测定,结合主成分分析及隶属函数计算对测定的指标进行综合评价和抗寒性排序。结果表明,低温胁迫下随着温度逐渐降低,MDA含量在一定温度范围内具有一定的波动性,但总体上呈现先上升后下降再上升的趋势;SOD活性在低温初期先出现短暂的下降后经抗寒锻炼呈现出上升又下降的趋势;柳杉不同无性系PS II最大光化学效率(Fv/Fm)和PS II的实际光合量子产量(Y(II))表现出相似的变化趋势,其值在0℃达到最高,0℃之后持续降低;光化学淬灭系数(qP)在低温初期无明显变化,0℃后随着低温胁迫的加剧而降低。柳杉不同无性系抗寒性具有显著差异,其中57#、68#和32#无性系抗寒性较强,3#、25#和42#无性系抗寒性较弱。     

长柄双花木叶性状异速生长关系随发育阶段和海拔梯度的变化

长柄双花木(Disanthus cercidifolius var. longipes)是一种仅分布于我国东南地区的珍稀濒危植物。为研究该物种叶性状异速生长关系和叶片资源利用策略及其随发育阶段和海拔梯度的变化规律,该文以分布于江西省不同海拔梯度的长柄双花木群落为研究对象,调查分析了群落中不同发育阶段长柄双花木植株的叶片面积、叶片体积以及叶片含水量与叶片干重之间的异速关系。结果表明:不同发育阶段植株之间叶性状异速生长关系有着显著差异。成树叶片面积的增长速度低于或等于叶片干重的增长速度,幼树、幼苗叶片面积的增长速度低于叶片干重的增长速度; 成树叶片体积与叶片干重呈等速增长,幼树、幼苗叶片体积的增长速度高于叶干重的增长速度; 成树叶片含水量的增长速度低于叶干重的增长速度,幼树、幼苗两性状间保持等速增长。海拔梯度对长柄双花木叶性状异速生长关系也有影响,植株叶体积和叶含水量与叶干重的异速生长指数在不同海拔间有显著性差异。在低海拔区域,叶体积与叶干重呈等速增长,叶含水量的增长速度低于叶片干重的增长速度。在高海拔区域,叶体积的生长速度低于叶干重的生长速度,叶含水量和叶片干重呈等速增长。这说明长柄双花木叶片资源投资策略随着发育阶段和海拔梯度的不同发生变化。成树主要将叶生物量投资于光捕获面积和同化结构,幼树和幼苗则主要投资于维管组织的建设。由于海拔升高会引起风力增大、光强增强和土壤理化性质改变,长柄双花木在中低海拔倾向于增大叶体积以抢占资源,在高海拔倾向于加强机械组织和维管组织的建设来抵抗外界因子干扰。     

福建大田栲树次生林优势种群结构与动态

在福建大田栲树(Castanopsis fargesii Franch.)次生林内,应用相邻格子法设置3 200 m2样地,进行优势种群结构和空间格局的研究.结果表明, 栲树种群、罗浮栲(C. fabri Hance)种群、樟树[Cinnamomum camphora (Linn.) Presl]种群结构呈金字塔型,栲树种群和罗浮栲种群从Ⅰ、Ⅱ级幼苗到Ⅲ级幼苗发育过程中出现死亡高峰; 3个优势种群从Ⅲ级幼苗向第4立木级的生长过程中,死亡率也很高.栲树、罗浮栲和樟树种群在不同发育阶段空间分布格局差别较大,栲树种群在幼树阶段为集群分布,中树及大树阶段为随机分布;罗浮栲种群在幼树阶段呈集群分布、中树阶段呈均匀分布、大树阶段呈随机分布;樟树种群在幼树及大树阶段呈均匀分布,中树阶段为随机分布.不同区组规模对种群空间分布格局产生影响.     

海南岛热带低地雨林刀耕火种弃耕地自然恢复过程中的群落构建

研究群落构建机制是群落生态学的一个重要目标, 群落动态过程中的构建规律对于了解群落演替机理有重要的作用。该文以海南岛刀耕火种干扰后自然恢复的10 hm ²热带低地雨林为研究对象, 通过比较不同恢复阶段的次生林(15年、30年和60年)和老龄林在幼苗、幼树和成年树群落的物种组成, 揭示次生演替过程中的群落构建规律。研究结果表明, 老龄林中不同径级群落的物种多样性及不同径级间的物种相似度显著高于各恢复阶段的次生林, 但优势种在群落中的比例低于各恢复阶段的次生林。随着自然恢复过程的进行, 次生林群落物种组成与老龄林的相似性也逐渐增大, 支持演替平衡理论。所有恢复阶段样地中幼苗的个体、物种丰富度和基于多度涵盖估计量(ACE)都低于幼树和成年树群落, 幼苗层物种组成与幼树、成年树也有较大差异, 说明新增到幼苗群落可能是一个难于预测的过程。研究结果说明了确定过程和随机过程共同决定了次生演替的群落构建。     

桂林岩溶石山青冈优势种群空间分布格局及关联分析

种群空间分布格局是研究种群特征、种间相互作用以及种群与环境关系的重要手段。青冈(Cyclobalanopsis glauca)是岩溶生态系统顶极群落的建种群，为进一步了解其种群空间分布格局特征，该研究根据样地调查规范对面积为60 m×60 m样地中的木本植物进行空间定位且进行每木调查，并运用点格局方法中的g(r)和L₁₂(r)函数对青冈幼苗(DBH<2 cm)、幼树(2 cm≤DBH<10 cm)和成树(10 cm≤DBH)进行空间分布特征和关联性分析。结果表明：(1)青冈种群的径级结构符合倒“J”型分布。(2)幼苗、幼树和成树在较小尺度上表现为聚集分布，而幼树和成树在中、大尺度上基本表现为随机分布。(3)不同径级个体空间关联性主要表现为幼苗与幼树在0～15 m尺度上呈正相关；幼树与成树在0～10 m尺度上呈不相关，而在10～15 m尺度上呈正相关；幼苗与成树在0～2 m尺度上呈不相关，而在2～15 m尺度上呈正相关。因此，青冈种群的分布格局及其关联性随空间尺度和发育阶段而变化，这是由种群自身的生物学特性、种内种间关系以及环境条件共同作用的结果。该研究...     

贵州闽楠天然种群特征、空间分布格局及空间关联分析

为更好地保护闽楠天然种群,探究闽楠天然种群特征、空间分布格局及其空间关联性,对针对性地提出保护措施具有重要意义。以贵州台江县登鲁村闽楠天然种群为研究对象,通过野外设置60 m×60 m固定样地,采用种群径级结构代替年龄结构、点格局分析方法分析闽楠种群年龄结构、不同生长阶段空间分布格局及其关联性。结果表明：（1）闽楠种群年龄结构呈倒"J"型分布,幼龄个体数量多,随着年龄增加,能够成功进入后期的个体数量急剧下降,死亡率高。存活曲线趋于Deevey-Ⅱ型,属于稳定型种群。种群在第5龄级（7.5 cm≤DBH<12.5 cm）的生命期望（e_x）最高。（2）闽楠种群分布格局由随机分布转向随机分布。在幼苗、幼树、中树阶段空间分布格局趋于集群分布,大树阶段趋于集群分布。（3）不同生长阶段之间空间关联性表现有所差异。小尺度上,大树与幼树呈负关联,大尺度上,两者呈正关联;小尺度上,幼树与幼苗、大树与幼树都呈正关联,大树和中树无关联,在大尺度上,大树和中树、幼树与幼苗、中树与幼苗以及中树和幼树都呈负关联且随着空间尺度的增加负关联性逐渐增强。总体而言,该闽楠天然种群较稳定,但对环境干扰敏感,幼龄个体因呈聚集分布受密度制约而竞争剧烈,成年个体则因对环境的竞争而呈随机分布。为维持种群的长期稳定,需要分阶段适时进行人工调控。     

三叶橡胶树束缚水指标与抗寒性关系

橡胶树北移至亚热带地区,冬季易受零上低温寒害。本研究表明:无性系及实生树叶片束缚水含量高者抗寒性强、低者为较弱。束缚水随温度降升而发生变化,自然降温至3℃,先引起剧烈升降波动,随着气温回升、日温差达到17℃,束缚水又不可逆地下降,使原生质脱水,呈现伤害。重害时会导致局部器官组织的干枯死亡。寒害变化过程也是失水反应的过程。本文以束缚水与总水量比值率作为越冬性检验指标,它与植株年龄、无性系及实生树的抗寒性关系极为密切。     

热带植物海巴戟抗寒株系选育

为了选育海巴戟（Morinda citrifolia）抗寒株系,拓宽种植范围,在云南元江选择8株海巴戟,采用石蜡切片法观察叶片解剖结构,并测量叶片的过氧化氢酶（CAT）、过氧化物酶（POD）、超氧化歧化酶（SOD）活性和丙二醛（MDA）含量,对抗寒株系的甘油-3-磷酸酰基转移酶（GPAT）活性和GPAT表达进行定量分析。结果表明,叶片解剖结构表明有4株海巴戟叶片的栅海比较高,细胞结构紧密,确定为抗寒性优良的候选株系（5、6、8和12号）。5号植株叶片经低温处理后的CAT、POD、SOD活性较高,MDA含量较低,确定为抗寒株系,且低温处理后5号植株叶片的GPAT活性和GPAT基因表达水平均高于不抗寒材料。因此,海巴戟叶片通过增加栅海比和细胞结构紧密度,同时GPAT基因迅速应答来提高抗寒性。     

AN ANALYSIS OF THE GROWTH RESPONSE OF YOUNG TOMATO PLANTS TO INFECTION BY VERTICILLIUM ALBO-ATRUM

Infection of seedling tomatoes with Verticillium albo-atrum checked growth but did not result immediately in leaf yellowing. Localized wilting occurred in some plants 2 weeks after the check to growth was evident. 8 weeks after inoculation, dry weights of leaf, stem and root were decreased by 72, 70, and 65% respectively.
Of the growth attributes studied, leaf area was most reduced by infection and this was due to a failure of the leaves to expand rather than to a fall in the rate of leaf production. Neither water nor nitrogen appeared to be limiting factors in this respect. The water content of infected leaves was not reduced until 6 weeks after inoculation, when leaf yellowing and necrosis had also appeared. The percentage N contents of stem, root and leaf of infected plants exceeded those of the healthy controls 24 days after inoculation. N uptake was not seriously impaired until 21 days later.
The photosynthetic efficiency of the green leaves of infected plants was reduced. The mean values for net assimilation rates were: Healthy 0.47 and infected 0.39 g./dm.²/week.
Plants, in which two-thirds of the root system had been killed by crushing, were placed in contact with mycelium in soil. This initial root injury did not significantly affect the growth of infected plants.
The data accord with a toxin theory of damage to infected plants, but the slow development of chlorosis and wilting symptoms in the young plants suggested a greater tolerance to the toxin than is found in older plants.     

THE RESPIRATION OF TOBACCO LEAVES AFTER SYSTEMIC INFECTION WITH TOBACCO MOSAIC VIRUS

The rate of CO, production per g. dry matter of the younger leaves of tobacco plants systemically infected with tobacco mosaic virus was about 10 yo less than that of comparable healthy leaves. Older infected leaves, showing well-developed mosaic symptoms, had the same respiration rate as comparable healthy leaves. These results were independent of seasonal change in light conditions during the growth of the plants. Older leaves, but not younger leaves, of infected plants had a lower initial water content, and both absorbed less water during the experimental period, than leaves from healthy plants. The effects of TMV infection on water content were so great that the rate of CO, production per g. fresh weight was sometimes significantly increased by infection. This reversal of the apparent effect of infection on respiration rate, depending on the basis of reference may partly account for contradictory results reported previously by other workers. Other causes for contradictory results are discussed.     

丛林式橡胶林内植物水分利用效率与叶片养分含量

选取西双版纳地区丛林式橡胶林为研究对象,以纯橡胶林为对照,分别在2016年干季(3月)和雨季(5、6、7月)进行取样,测定两个样地内植物叶片δ13C值,比较植物水分利用效率,测定叶片C、N、P含量,计算叶片N/P值,分析植物对养分的利用与竞争关系,并综合分析植物水分利用效率与养分之间的相关性。结果表明,干季橡胶树受到干旱胁迫,其水分利用效率显著高于雨季,此时叶片N、P含量也显著高于雨季;丛林式橡胶林内橡胶树水分利用效率低于纯橡胶林内橡胶树,叶片N、P含量和N/P值均高于纯橡胶林中橡胶树;两个样地内不同植物与不同时间的水分利用效率,叶片C、N、P含量和N/P值均存在显著差异;相关性分析表明,水分利用效率与叶片N、P含量呈正相关,与叶片C含量、N/P值呈负相关。因此,丛林式橡胶林内橡胶树能更好地应对干旱,具有较强的养分获取能力。该研究揭示了丛林式橡胶林内植物水分利用效率以及养分利用特征,表明丛林式橡胶林是一种值得推广的农林复合生态系统。     

Leaf Water Diffusion Resistance in Clonal Tea (Camellia sinensis L.): Effects of Water Stress, Leaf Age and Clones

Leaf diffusion resistance was influenced by leaf age in well-wateredand water-stressed clonal tea plants. In well-watered plantsand in two of the three clones studied, young leaves showeda significantly lower diffusion resistance than old leaves.In water-stressed plants young leaves always exhibited a higherdiffusion resistance than old leaves. The highest diffusionresistance, irrespective of leaf age and water stress, occurredin clone DN which is known to be the most drought tolerant ofthe three clones studied, suggesting that drought tolerancein clone DN is caused, at least in part, by a stomatal regulationmechanism. Water release characteristic curves for the threeclones indicated differences in the water content-water potentialrelationship between young and old leaves as well as betweenclones. The drought tolerant clones had a higher relative watercontent for a given water potential compared with the drought-susceptibleclone. Camellia sinensis L., tea, diffussion resistance, water stress     

THE EFFECT OF INFECTION WITH BEET YELLOWS AND BEET MOSAIC VIRUSES ON THE CARBOHYDRATE CONTENT OF SUGAR-BEET LEAVES, AND ON TRANSLOCATION

The loss of total carbohydrate (sugars and starch) per cent of residual dry matter (dry matter less total carbohydrate) during a period of darkness from leaves of sugar-beet plants infected with yellows virus was as great as that from the leaves of healthy plants. The conclusion of previous workers, based on the results of the Sachs iodine test for starch and the occurrence of 'phloem gummosis' in infected plants, that starch accumulates in infected leaves because translocation is prevented by blockage of the sieve-tubes, is therefore incorrect.
Older leaves of infected plants had a higher content of reducing sugars and sucrose, and usually but not invariably of starch, both at the beginning and end of the dark period, than comparable leaves of healthy plants. By far the greater part of the increase was in reducing sugars. In leaves taken in late September from infected plants growing in the field, 20 % or more of the total dry matter was present as reducing sugars. The reducing sugars in both healthy and yellows-infected leaves were shown by paper chromatography to be glucose and fructose in approximately equal amounts.
Accumulation of carbohydrate in infected leaves is probably not a passive consequence of differences in carbohydrate production, distribution and utilization, but is attributable to changes in the physiology of the cells of the leaf.
The carbohydrate content of sugar-beet leaves was little affected by infection with beet mosaic virus.
Yellows-infected leaves had a lower water content per cent of fresh weight than healthy leaves. This was accounted for by the higher carbohydrate content of infected leaves, for the ratio of water: residual dry matter was not affected by infection or was slightly reduced. This implies that hydration was independent of carbohydrate content.     

TRICHOME MORPHOLOGY AS AN INDICATOR OF HIGH RUBBER BEARING GUAYULE (PARTHENIUM ARGENTATUM GRAY) PLANTS IN NATIVE POPULATIONS

Parthenium argentatum Gray (guayule) and P. incanum (mariola) grow in close associations in their native habitat of Mexico. Variation in rubber concentration and morphology of guayule has been known for a long time. Studies of over 75 native guayule plants indicated the presence of at least three prominent forms of guayule plants. Group I guayule plants have oblanceolate leaves and leaf margins are entire to two-toothed. T-shaped leaf trichomes are with centrally attached stalk and cap cell with two blunt ends. Plants in this group are high in rubber, containing on the average 17% rubber. Group II guayule plants have narrow elliptic leaves and leaf margins are entire to four-toothed. T-shaped trichomes have an acentrally attached stalk and a cap cell with short end blunt, long end pointed and straight. Rubber content in these plants averages 10%. Group III guayule plants have ovate leaves and leaf margins are four- to eight-toothed. T-trichomes have an acentrally attached stalk and a cap cell with short end blunt, long end pointed and wavy or curved. These plants on the average contain 6% rubber. Morphological as well as biochemical data indicate the presence of mariola genes in the last two groups of plants and this has resulted in an increase in trichome length and a decrease in the rubber content. Group II guayule plants are of more common occurrence than the others. Based on the data presented here, high rubber bearing guayule plants in native stands can be easily selected by analyzing trichome morphology.     

Possibilities to reduce adverse effects of salinity by indole-3-acetic acid

Salinity caused a consistent reduction in the growth of cowpea plants and water content in their leaves. The total as well as the pigment fractions, except carotenoids, exhibited lower values than those of control plants at almost all salinity levels. With the rise of salinization, the total nitrogen and potassium contents in the leaves were decreased but the sodium content was increased and phosphorus content was not significantly affected as compared with the controls. The application of IAA to salt-treated plants increased the water content in the leaves but it had no effect on the number of leaves and the stem length. The pigment contents in the leaves were either promoted or inhibited with the application of IAA, depending upon the level of salinization. The application of IAA to plants irrigated with water of the highest salinity level was effective in increasing the potassium content in the leaves as compared with the control, but it had no effect on the other mineral elements.     

Changes in ion and water content of individual shoot organs in a salt-tolerant and a salt-sensitive clone of Agrostis stolonifera L. during and subsequent to treatment with sodium chloride

Abstract Individual leaves and stems were analysed for Na⁺, Cl^?, K⁺ and water content in two clones of Agrostis stolonifera differing in salt resistance, during 14 d of treatment with NaCl, 100 and 200 mol m^?3, and a further 7 d in a salt-free medium. Great differences in ion and water content were revealed between individual organs, and organ-by-organ analysis also emphasized the differences between the clones better than whole shoot analysis. In both clones, Na⁺ and Cl^? accumulated to the greatest degree in the older leaves, but for corresponding organs, the concentrations were lower in the more tolerant clone. In the sensitive clone, the lowest leaves dehydrated in 200 mol m^?3 NaCl and failed to recover, while the plants of the more resistant clone maintained viable water content in all organs. In the resistant clone, K⁺ concentration decreased less in response to salt treatment than in the more sensitive clone. For a full appreciation of the plants' reactions, it was found necessary to express the analytical data on several bases, namely, per unit dry-weight, unit water, and total ion-content.     

超高产杂交稻不同生育期的光合色素含量、净光合速率和水分利用效率

 较为系统地研究了两个超高产杂交稻‘两优培九’、‘华安3号’和多年来大面积推广的常规杂交稻‘汕优63’不同生育期的光合色素含量、净光合速率和水分利用效率。结果表明,在苗期,3个杂交稻的单位叶面积的叶绿素（Chl）含量差别不大,类胡萝卜素（Car）的含量以‘汕优63’为最高。然而,随着发育阶段的推进,到分蘖期,尤其是抽穗期剑叶的单位叶面积Chl和Car含量,两个超高产杂交稻高于‘汕优63’。从苗期到抽穗期,超高产杂交稻‘两优培九’和‘华安3号’的净光合速率（Pn）都比‘汕优63’高,而在苗期的午间强光条件下和分蘖期的早晨以及抽穗期的早晚相对弱光条件下其Pn的差别尤为显著。在苗期,‘汕优63’的水分利用效率（WUE）略高于‘两优培九’和‘华安3号’;到分蘖期和抽穗期,在上午10时之前和下午14时以后的时间段,则是两个超高产杂交稻明显高于‘汕优63’。这些结果说明,超高产杂交稻‘两优培九’和‘华安3号’不仅有较高的Pn和较强的抗光抑制能力,而且还能充分利用早晨和傍晚较弱的光强进行光合作用,这些是它们之所以高产的重要生理基础。此外,超高产杂交稻在生长发育的中后期（分蘖期和抽穗期）具有较高的WUE,有利于节约农业用水。