不同紫色土上几种树苗结瘤固氮及其对植株生长的影响

树木固氮是森林土壤氮素的重要来源,许多固氮树种能在瘠薄的土壤上生长,对土壤的改良起着重要作用;在混交林中作伴生树种有效地促进主林木的生长;农区常用它作有机肥源,调节氮素的供需平衡,促进农业增产。固氮树种的研究和利用逐渐引起人们的重视(Bo-nd,1976;Sprent,1979)。紫色土是四川盆地的主要土类,该区森林植被覆盖率低,水土     

三种土壤类型中南天竹差异性的研究

石灰岩地区的生态重建和植被恢复问题一直备受关注。用盆栽法,研究了黑色石灰土、紫色土、黄壤三种不同土壤类型对南天竹的影响。试验表明:除紫色土中的南天竹叶片P含量高于其他两种土壤,三者之间差异均达到显著水平(P<0.05)外,黑色石灰土中的南天竹叶绿素、类胡萝卜素、叶片的N、可溶性糖和蛋白质含量均高于其他两种土壤,其差异性与黄壤达到显著水平(P<0.05),与紫色土的差异性未达到显著水平(P>0.05),而紫色土与黄壤的差异也达到了显著水平(P<0.05)。各项测定指标的总体情况是黄壤<紫色土<黑色石灰土。该试验证明将南天竹用于石灰岩地区的植被恢复和经济发展是完全可行的。     

铅胁迫对欧美杂交杨幼苗碳、氮和磷积累与分配的影响

为深入了解欧美杂交杨(Populus deltoids × Populus nigra)在不同铅(Pb)胁迫条件下的生长适应特性, 采用盆栽控制试验, 研究了长江上游典型酸性紫色土和钙质紫色土上欧美杂交杨碳(C)、氮(N)和磷(P)积累与分配特征对不同浓度Pb胁迫(CK: 0 mg·kg^-1; T1: 200 mg·kg^-1; T2: 450 mg·kg^-1; T3: 2000 mg·kg^-1)的响应。欧美杂交杨总C、N和P积累量在两种土壤中均表现出随Pb胁迫程度的增加而降低的趋势, 且钙质紫色土中欧美杂交杨总C、N和P积累量在各处理浓度下均高于酸性紫色土。Pb胁迫处理明显改变了欧美杂交杨各器官C、N和P的分配格局。与对照相比, Pb胁迫处理使酸性紫色土中欧美杂交杨细根C、N和P积累量的比例明显增加, 叶C、N和P积累量的比例则呈现出降低的趋势。相对于酸性紫色土, 钙质紫色土中欧美杂交杨细根C、N和P积累量的比例明显降低, 其叶C、N和P积累量的比例则表现出增加的趋势。两种土壤中欧美杂交杨P的利用效率均表现出随Pb胁迫程度的增加而增加的趋势, 而T2、T3处理下两种土壤中N的利用效率均显著降低。这些结果表明, 在N素缺乏的情况下, 酸性紫色土中欧美杂交杨P的利用效率显著低于钙质紫色土, 因此酸性紫色土中植物C、N和P积累、分配与利用更易受到Pb胁迫的影响。同时也表明, 钙质紫色土中欧美杂交杨通过改变养分分配格局将资源更多地分配于养分利用器官维持自身的生长, 能更好地适应Pb胁迫环境。     

桤木叶量的初步研究

桤木(Alnus cremastogyne Burk),落叶乔木树种,主要分布于四川盆地,贵州、陕西、云南等省亦有分布。因生长迅速、适应性强,且具根瘤能固氮改良土壤,是盆地农区最广泛的荒地和四旁绿化造林树种之一。盐亭地区,属深丘低山地形,以林山公社为代表,近年来,大力营造桤木和柏木(Cupressus funebris Endl)的混交林和桤木纯林,取得了较好的效果,桤木占总造林面积的一半左右。     

不同磷浓度植株残体降解对紫色土磷素有效性的影响

植株残体降解可直接或间接地影响土壤磷素的有效性,为探讨不同磷浓度植株残体降解对紫色土磷分级体系的影响,结合31P核磁共振分析技术,选取了3种磷浓度不同的植物残体与两种紫色土进行室内模拟培养试验,得出了以下研究结论:(1)添加植株残体显著增强了紫色土呼吸强度,且紫色土分级体系中的活性磷含量均高于对照处理(2)31P-NMR分析结果得知,植株残体的正磷酸盐、磷酸单酯占浓缩液全磷比例的90%以上,高磷植株的正磷酸盐和磷酸单酯含量显著高于中磷和低磷植株,土壤磷素有效性的变化与植株残体的正磷酸盐和磷酸单酯含量有关;(3)紫色土分级体系中的活性磷在0 d含量最高,随着培养周期的延长,土壤磷素有效性会出现降低的趋势;酸性紫色土的累积呼吸强度、分级体系中活性磷(Resin-P、Na HCO3-Pt)所占比例均高于中性紫色土,与土壤钙含量有关。综上所述,植株残体的磷浓度越高,更有利于提高土壤磷素的有效性,本研究结果为农业生产中秸秆还田技术提供了理论参考。     

不同土壤-南天竹系统的土壤酶活性分异

石灰岩退化生态系统的恢复离不开土壤基质的改善。采用盆栽法,研究了生长在黑色石灰土、紫色土、黄壤3种不同土壤类型中的南天竹土壤酶活性的情况。试验表明:淀粉酶、碱性磷酸酶、天门冬酰胺酶的活性均表现出黑色石灰土>紫色土>黄壤,三者之间差异显著(p<0.05)。而脲酶、多酚氧化酶和过氧化物酶活性则是紫色土>黑色石灰土>黄壤,三者之间差异也达到显著水平(p<0.05)。土壤理化性质与土壤酶活性的相关分析说明土壤pH和全磷(P)对土壤酶的活性影响不大,而不同土壤类型中的全氮(N)和土壤含水率与部分土壤酶活性呈显著相关。不同土壤类型的土壤酶相关性表现各异。     

几种豆科树木结瘤固氮的初步研究

 作者通过野外调查和盆栽试验,探讨了几种豆科树种的结瘤固氮特征,土壤条件的影响和植株生长。木豆、山毛豆、刺槐在南亚热带褐红土种植,山合欢、刺槐在中亚热带紫色土种植,对绿化荒山荒地、改良土壤和促进生态平衡具有重要意义。     

3种土壤类型下红椿幼苗对铅胁迫的光合响应

采用盆栽试验,研究钙质紫色土、酸性紫色土和冲积土3种土壤类型上生长的红椿幼苗在不同浓度(0、200、450、2 000mg·kg-1)铅(Pb)胁迫下的光合生理响应,探讨红椿在不同土壤类型下Pb污染的生态适应性,为木本植物的重金属修复提供理论依据。结果表明:(1)3种土壤类型下,红椿幼苗叶片叶绿素a、叶绿素b及叶绿素总量随Pb胁迫浓度的增大呈总体降低的趋势,叶绿素含量在钙质紫色土上受Pb胁迫的影响不大,而在酸性紫色土和冲积土上降低明显。(2)不同土壤类型的红椿光合响应曲线变化趋势十分相似,红椿幼苗叶片的净光合速率均随Pb胁迫程度的加大呈先增加后降低的趋势且差异显著,并在Pb浓度为200和2 000mg·kg-1时光合速率分别达到最大值和最小值。(3)随着Pb胁迫浓度的增大,红椿的最大光合速率、表观量子利用效率、光补偿点等光合生理指标都发生了显著改变,说明Pb胁迫严重影响红椿幼苗的光合作用。研究表明,高浓度的铅抑制红椿幼苗叶片叶绿素的合成,从而抑制光合作用的强度,且铅胁迫的浓度越高,叶绿素含量越低,光合作用受到的抑制越强;较低浓度的Pb处理(200和450mg·kg-1)对酸性紫色土和冲积土上红椿的净光合速率影响很小,而对钙质紫色土上红椿的最大净光合速率的抑制最为明显。     

紫色土造林树种苗期生态条件的研究Ⅱ

本文讨论了19种树苗在几种不同性质和肥力水平紫色土上的生态反应和适应性,利用方差分析的方法阐明了不同土壤条件幼苗生长差异的显著性,利用簇群分析揭示了不同树种的生态相似性,根据幼苗的相对高度评价了土壤的肥力。     

滇东南普阳盆地含煤地层孢粉组合特征及其年代

云南地处青藏高原东南缘, 生物多样性丰富, 季风气候特征明显。新生代剧烈的构造活动形成了众多山间盆地, 其间保存了大量精美的植物化石, 是探讨新生代以来植被、植物多样性和地球环境演变的理想地区。但是长期以来, 由于地层年代学证据的缺乏, 这些新生代沉积盆地的地质年代还存在很大争议。本研究通过对滇东南地区富宁县普阳盆地的含煤地层开展深入的孢粉学研究, 探讨盆地含煤地层年代及其古气候演化过程。剖面下部煤层孢粉组合以杉粉属(Taxodiaceaepollenites)为主, 指示以杉科为主的湿润沼泽森林, 冬春季相对湿润; 剖面上部孢粉组合指示以常绿栎类为主的亚热带常绿‒落叶阔叶混交林, 生长山核桃粉属(Caryapollenites)、冬青粉属(Ilexpollenites)、胡桃粉属(Juglanspollenites)、枫香粉属(Liquidambarpollenites)等亚热带常见树种, 气候温暖湿润, 季节分明。结合新发现的哺乳动物化石证据和周边地区不同地质时代的孢粉组合, 普阳盆地含煤地层的沉积时代应为晚始新世; 同时, 孢粉组合也表明滇东南地区植被现代化面貌至少在晚始新世就已经开始出现。     

中国核盘菌科分类研究概况

本文简要回顾我国核盘菌科真菌的研究历史,尤其是最近十年的进展,更正了过去此科分类和命名中的一些问题,列出我国目前已知核盘菌科12属42种,并提供属的检索表;其中美洲杯盘菌(Ciboria americana Durand)为我国新记录。同时,指出对此科进一步深入探讨的方向。描述了新种贵州杯盘菌(Ciboria guizhouensis w.-y.Zhuang),模式保存在中国科学院微生物研究所真菌标本室。     

日本菟丝子寄生菌致病力的专化性研究

日本菟丝子(Cuscuta japonica)吸取不同寄主植物的营养,经过营养代谢其机体内的过氧化物酶同工酶的活性或酶带数发生变化,从而改变了它对胶孢炭疽菌菟丝子专化型[Col-letotrichum gloeosporioides(Penz.)Sacc.f.sp.Cuscutael]同一菌株的抗性,以此为依据,采用寄生在不同植物上的日本菟丝子做为鉴定寄主,可以鉴别出胶孢炭疽菌菟丝子专化型中不同菌株的致病力差异。 初步认为:龙眼、桂花、柚子和冬青上的紫色菟丝子及泡桐、桂花和冬青上的黄色菟丝子可以作为鉴定寄主。     

OBSERVATIONS ON THE EFFECT OF GROWTH-STIMULATING COMPOUNDS ON THE HEALING OF WOUNDS ON APPLE TREES

Wounds were made at various times of the year on the trunks and large branches of apple trees with a 1 in. bit and treated with a number of organic compounds in lanoline paste. The healing of these wounds was followed through two growing seasons by tracing and measuring the area of exposed wood at different times after wounding.
Callus growth was practically confined to the summer months. Development of callus was improved by applications of lanoline, and the lanoline effect could be further enhanced in the early part of the first growing season following treatment by the addition of certain growth-stimulating compounds including 4-chloro-3:5-dimethylphenoxyacetic acid and 2:4-dichlorophenoxyacetic acid. Indolyl-3-butyric acid probably also caused some stimulation. After the period of initial stimulation the rate of callusing was approximately the same on treated as on untreated wounds.     

紫胶虫最佳生长地的植被条件分析

本文在对紫胶产区进行调查的基础上,分析了云南紫胶虫最佳生长地的植被条件、对其中的四种群落类型从植物种类成分、群落结构和群落生态等方面进行分析。根据丰富的寄主资源和有利于紫胶虫越冬的气候条件指出“暖热性稀树灌草丛”及“河谷季雨林次生林和灌丛”是云南紫胶虫及其主要寄主植物的适生类型。本文在总结紫胶产区的经验基础上,提出了开发利用的意见和改造的措施。     

松嫩平原两种碱蓬群落土壤种子库通量及幼苗死亡的分析

角碱蓬和翅碱蓬都是１ａ生耐碱性较强的藜科植物。在松嫩平原碱化草甸２个固定的单优碱蓬群落土壤中有活力种子的数量动态和种群动态的研究结果表明：土壤种子库存量在尚未萌发输出以前为最大,角碱蓬群落为２２２６０粒／ｍ＾２,翅碱蓬群落为３７２３０粒／ｍ＾２。整个生长季均有种子输出,２群落的种子库存率随着时间呈渐近形式规律地下降。现存植株数量角碱蓬种群以５月上旬最大,为１９４８０株／ｍ＾２,翅碱蓬则在４月上旬最     

ON THE MECHANISM OF DECUSSATE PHYLLOTAXIS: BIOPHYSICAL STUDIES ON THE TUNICA LAYER OF VINCA MAJOR

Phyllotaxis theory typically assumes that an acropetal influence from recently formed leaves acts on the apical dome to initiate new leaves. Biophysical theory postulates that established plant organs elongate because their primary walls, particularly those in the organ surface layer, are transversely reinforced by cellulose to give the organ overall hoop reinforcement. These two postulates are combined here in a biophysical theory for phyllotaxis. The essential acropetal influence from young leaves is proposed to be the stretching of the adjacent dome tissue by the growth of leaf bases. Cytoskeletal responses on the dome produce reinforcement patterns which initiate new hoop reinforced leaves. Growth of these leaves remodels the dome for the next round of organs. Data pertinent to this theory are presented here for Vinca major. The surface (tunica) layer of the apical dome was isolated by paradermal cuts. Using polarized light, the cellulose alignment in this surface layer was determined, cell by cell, for various stages of the plastochron. The growing dome is typically elliptical, with the major axis shifting by 90° during each plastochron. The periphery of the dome always has cellulose oriented parallel to its margin; the central region, when the major axis is pronounced, has reinforcement normal to this axis. During the plastochron this reinforcement pattern is modified, by plausible biophysical mechanisms, to account for the three major activities of the dome: 1) production of a hoop-reinforced leaf at each end of the ellipse, 2) formation of a hoop-reinforced stem segment, 3) revision of dome structure to produce the same initial reinforcement pattern as at the start of the plastochron, but at 90°.     

白刺胚乳早期发育的超微结构研究

白刺(Nitraria sibirica)胚乳发育经历游离核阶段、细胞化阶段和被吸收解体阶段。游离核胚乳沿胚囊壁均匀排列为一层,胞质浓厚,其中有丰富的质体、线粒体、高尔基体、内质网和各种小泡等细胞器。珠孔区域的胚囊壁具发达的分枝状壁内突,而周缘区域的胚囊壁具间隔的钉状内突,内突周围的细胞质中具多数线粒体和小泡。胚乳细胞化时,初始垂周壁源于核有丝分裂产生的细胞板。在细胞板两端开始壁的游离生长,一端与胚囊壁相连接,另一端向心自由延伸。壁的游离生长依赖于小泡的融合。早期胚乳细胞具大液泡,具核或无核,细胞质中有大量的线粒体,质体缺乏,其壁仍由多层膜结构组成。     

INFLUENCE OF NEIGHBORS ON TREE FORM: EFFECTS OF LATERAL SHADE AND PREVENTION OF SWAY ON THE ALLOMETRY OF LIQUIDAMBAR STYRACIFLUA (SWEET GUM)

Liquidambar styraciflua (sweet gum) saplings were open grown (control), guy-wired to prevent wind-induced sway (constrained), or guy-wired within open-topped shade cloth cylinders to simulate shading by neighboring trees (shaded). Mechanical stability was assessed after 2 years of growth by field measurement of whole-tree flexibility and with the critical buckling height predictions of five allometrical models. Data from this experiment are supplemented with measurements of sweet gum trees growing in a 9-year-old pine plantation; individuals crowded but not overtopped by pines are compared with similar-aged trees growing in openings within the plantation. Changes in aboveground architecture were stimulated by both prevention of sway and lateral shade but the effect of the latter was most pronounced; shaded saplings approached or exceeded their calculated critical height and buckled under their own weight when the shade cloth cylinders were removed. Rates of aboveground biomass acquisition, total leaf area, wood density, and wood elastic moduli did not differ among the three treatments; changes in stem allometry accounted for most of the observed differences in tree stability. Sweet gum trees growing in a pine plantation responded similarly to neighbors; crowded trees had larger height: diameter ratios and more closely approached their calculated critical heights than did trees growing in the open. Sweet gum saplings growing in dense stands of similar-sized plants may surmount their neighbors by allocating relatively more wood to height growth than to girth increment.     

冬小麦单产的光谱数据估测模型研究

 本文在分析冬小麦群体经济产量与叶面积系数关系的基础上,以地面实测冬小麦反射光谱数据为依据,提出了一种新的动态VI-产量模型,即LAD-产量模型。该模型具有冬小麦生育后期(抽穗一灌浆末期)光合面积和光合时间等信息,其冬小麦单位面积产量(简称单产)估测精度为98%。另外,本文根据常用的某一特定生育期VI-产量模型,用冬小麦各生育期的VI值分别估测小麦单产,确定山东省禹城市冬小麦的灌浆中期为最佳估产时间。此时期．小麦单产估测精度为96%。