VARIATIONS IN THE LEAF OILS OF THREE SPECIES OF JUNIPERUS

Leaf oils from Juniperus occidentalis, J. osteosperma, and J. califomica were analyzed qualitatively and quantitatively for characteristic chemical composition. Seasonal, diurnal, and local microcline variation was quantified. Neither microcline nor seasonal variation appeared to have a significant effect on the leaf oil composition, although some variation was observed. A definite trend toward diurnal cycling was detected and tentatively linked to air temperature fluctuation from dawn to dark.     

顶生金花茶木材构造的研究

似半环孔材;梯状复穿孔,横隔条数多;轴向薄壁组织星散聚合为主;射线组织异形Ⅰ型为主,2列射线占79％,多列射线融合成单列现象可见;细胞质及细胞核明显;结晶体菱形,仅见于方形或直立细胞。木材构造与柠檬黄金花茶Comellia limonia C.F.Liang et S.L.Mo相近似。     

三种姬鼠的染色体比较研究

本文采用染色体分带技术（Ｇ－,Ｃ－带和银染色）,对中华姬鼠（Ａｐｏｄｅｍｕｓｄｒａｃｏ）、大林姬鼠（Ａ．ｐｅｎｉｎｓｕｌａｅ）和大耳姬鼠（Ａ．ｌａｔｒｏｎｕｍ）的核型进行了观察分析。结果表明：３种姬鼠的２ｎ均为４８。中华姬鼠的染色体均为端着丝点染色体。大林姬鼠的常规核型中,除１对中着丝点染色体（Ｎｏ．２３）外,其余均为端着丝点染色体。大耳姬鼠的核型中,有１３对端着丝点染色体,２对亚端着丝点染色体,１对亚中着丝点染色体和７对中着丝点染色体。中华姬鼠Ｃ－带核型中,所有染色体着丝点Ｃ－带都呈强阳性,异染色质非常丰富,Ｙ染色体整条深染。在大林姬鼠Ｃ－带核型中,Ｎｏｓ．７,１１,１５,２１,２２着丝点Ｃ－带弱化甚至近阴性,其余染色体着丝点异染色质Ｃ－带都呈现程度不同的阳性。且Ｎｏｓ．２,４,７有强弱不同的端位异染色质带。Ｘ染色体着丝点区有大块的异染色质斑带出现,Ｙ染色体整条深染。大耳姬鼠除Ｎｏｓ．３,４,１０,１２,１３染色体着丝点Ｃ－带很弱外,其余染色体着丝点Ｃ－带均呈阳性,并有８对（Ｎｏｓ．１６－２３）染色体出现异染色质短臂。从总体上看,大林姬鼠和大耳姬鼠的着丝点异染色质明显比中华姬鼠的少。中华姬鼠的Ａｇ－ＮＯＲ     

OBSERVATIONS ON THE FINE STRUCTURE OF CALLIXYLON WOOD

Secondary wood of three species of Callixylon of Lower Mississippian age, preserved by three different modes (fusinization, silicification, and phosphatization), have been studied and characterized in detail. Problems of interpretation at the SEM level of permineralized woods, both containing (silicified wood of Callixylon erianum) and essentially lacking (phosphatized wood of C. arnoldii) original organic cell wall material, are analyzed and discussed. In particular, it is concluded that the flat to curved surfaces showing no evidence of apertures, observed in bordered pit pairs, commonly represent pit membrane surfaces. It is accepted, however, that some concave surfaces might be the mineral accretion surfaces of incomplete pit cavity casts as proposed by Leo and Barghoorn (1976). Regions between groups of pits, previously interpreted as crassulae, may be artifacts of preservation. The fusinized wood has the general appearance of charcoal, but unlike commercially produced charcoal provides evidence of its original microfibrillar structure. The origin of fusain in the fossil record is discussed, and it is concluded that it probably had several origins, including forest fire. Since charcoal can be produced naturally in the absence of O₂ (Brown and Davis, 1973), the suggestion that fusain (charcoal) in the geologic column provides a basis for “assessing oxygen levels in paleoatmospheres” (Cope and Chaloner, 1980) is not supported. Natural sites of fusain production in the absence of O₂ are regions of vulcanism and organic sediments inhabited by anaerobic microorganisms. A circular pattern of crystal orientation in the pit borders of C. arnoldii is interpreted to represent the original microfibrillar pattern. Pit apertures in C. arnoldii are shown to be circular to slightly elliptical. Interpretive evidence of heterogeneous pit membranes in C. arnoldii suggests but does not prove the presence of a torus. The distinctive central region in some pit membranes of the fusinized wood of Callixylon sp. might represent accumulations of waste metabolites. It is argued that a torus would be highly adaptive in large pits with circular apertures.     

圆籽荷属木材构造的研究

山茶科圆籽荷属(Apterospefma)木材为散孔材至半环孔材,管孔细,射线细,薄壁组织肉眼下不见,密度中偏大,纹理直,结构细。微观构造:在导管相互间纹孔式对列夏导管分子穿孔梯状的横栅24—77条,射线异形Ⅰ型。射线与导管问纹孔为较大不规则形单纹孔,对列,薄壁组织星散.1—2个细胞。     

子叶节区理论与木材结构的演化

从系统发育看,出现最早的应是早已灭亡的乔木状蕨类植物的隐花植物式木材,例如：Ｌｅｐｉｄｏｄｅｎｄｒｏｎ,ｓｐｈｅｎｏｐｈｙｌｌｕｍ等。现存的都是出现在古生代末期和中生代以后的显花植物式木材,它包括裸子植的的叶子树材与被子植物的痴味树材。     

从世界栗属植物研究的现状看中国栗属资源保护的重要性

栗属（Castanea）植物世界上有7个种,广泛分布于北半球温带的广阔地域[1]。分布在亚洲的4个种：中国板栗（C．mollissimaBI．）、茅栗（C．SequiniiDode）和锥栗（C．henryiRehd．＆Wils．）分布在中国大陆;日本栗（C．crenataSieb．＆Zucc．）分布在日本及朝鲜半岛。分布在北美洲的有2个种：美洲栗〔C．den－tata（Marsh．）Brokh．）和美洲榛果栗（C．PumilaMill．）。美洲榛果栗曾划分为6个种：C．Pumila、C.Ozarkensis（Ashe）、C．ashei（Sidw．）、C．alnifolia（Nutt．）、C．floridena（Ahe）,和C．paucispina（Ash…     

初期采脂对马尾松木材构造的影响

广东省韶关林场采用标准的采脂工艺,在其马尾松人工林进行了两年的初期采脂试验。 在这些马尾松的采脂树的采脂盘上,主要呈现泌脂和木材增生,而在其下方距离0.5m的影响盘上。仅有一些创伤轴向树脂道和树脂囊。创伤树脂道使其邻近的轴向管胞的形状不规则,又与树轴倾斜近45°。 从山中试验区不同的松树林分,在其对照盘(对照树的)、影响盘上,自髓向外每隔一个生长轮的离析材料;另在采脂盘上密切邻近采脂面两侧,自圆盘周围向内各选4轮材料;分别测定轴向管胞的长度,得知这些30(20)年生的马尾松树仍在幼态期间,其管胞长度一般是增加的;至于采脂面两侧的管胞却显出不同程度的减短,其中一些管胞呈现种种不规则形状。     

四种草螽雄性鸣声的研究

对分布于我国的长瓣草螽Conocephalus(Anisoptera)gladiatus,中华草螽C.(Amurocephalus)chinensis,悦鸣草螽 C.(Anisoptera)melaenus和斑翅草螽C.(Anisoptera)maculatus雄性鸣声进行了分析.研究结果表明,这4种草螽雄性鸣声的时域波形较简单,鸣声均由1种类型的脉冲组序列构成.长瓣草螽雄性鸣声每个脉冲组持续时间约0.13 s,脉冲组间隔约0.12 s,每个脉冲组通常由8脉冲构成,鸣声的频率范围5～20 kHz.中华草螽雄性的鸣声脉冲组由2个脉冲构成,每次鸣叫持续时间约为3.3 s,两次连续鸣叫间隔约10.5 s,鸣声频率范围为20 Hz～20 kHz.斑翅草螽雄性鸣声的脉冲组由10～13个脉冲构成,脉冲组持续时间2.1～2.5 s,两次连续鸣叫间隔时间约为3 s;鸣声频率从5.5 kHz到高于20 kHz.悦鸣草螽雄性鸣声由单一规则的重复脉冲组序列构成,每个鸣声脉冲组持续时间约0.035 s,脉冲组间隔约0.023 s,每个脉冲组由3个脉冲构成,脉冲组重复率20/s,鸣声频率6.0～20.0 kHz.     

中国葡萄属植物叶片气孔特征的研究

对起源于中国的葡萄属(Vitis L.)20个种或变种叶片气孔特性进行了观察研究。结果表明:气孔纵径对葡萄属种的分类有较大的价值;气孔比密度(叶片上所有气孔复合体面积与叶片面积之比)与叶片大小呈极显著正相关;气孔密度与气孔纵径呈极显著负相关;所有观察种类的叶片气孔类型均为不规则型。     

龙州锥木材构造小记

<正> 材料与方法 供切片用的木材标本由梁健英先生(K0658A)采自广西壮族自治区隆安县,其平均直径为2.35厘米。于横切面上,从髓向外连续选取木样2个;依照一般方法,完成本材显微研究制片。     

THE SEASONAL CYCLE OF PHLOEM DEVELOPMENT IN JUNIPERUS CALIFORNICA

In Juniperus californica, all sieve cells of the previous season's phloem growth increment overwinter in a mature state. Initiation of cambial activity begins in early March and, by the end of March, the oldest sieve cells that overwintered lose their contents and die. By mid-April, even the youngest sieve cells of the previous season's growth increment have lost their contents. The period of greatest cambial activity begins in the last half of April and continues through May. With the slowing of cambial activity in June, callose begins to collect on the sieve areas of the first-formed sieve cells of the new increment. By July, the cambium and phloem are in a dormant state. Initiation of phloem production precedes that of the xylem by about 1 month. Production of new xylem and phloem ceases simultaneously in July.     

中国稀有家具用材树种生态学特性及木材学特性

介绍了我国高级家具用材树种的分布、生态学特性、木材宏观构造、木材加工工艺性质及树种资源保护和利用情况。研究表明,我国高级家具用材树种较少,还不到10种,其中大多数分布在我国热带、亚热带地区。我国高级家具用材树种利用过度,其中麻楝、降香黄檀已很少见,林分径级下降,资源面临濒危状态。因此,对这些种树的保护和人工造林越来越重要和迫切。