THE ROLE OF RESERVES IN LEAVES,BRANCHES, STEMS,AND ROOTS ON SHOOT GROWTH OF RED PINE

By defoliation, girdling, and various combinations of these before the growing season began, the role of foods in old needles, branches, main stems, and roots on shoot growth of 8-yr-old red pine (Pinus resinosa) trees was studied in northern Wisconsin. Defoliation and girdling, alone or in combination, reduced shoot growth but defoliation reduced shoot dry weight more than it reduced shoot elongation. Reductions in shoot growth due to treatment were in the following decreasing order: branch girdling + needle removal > girdling at stem base + needle removal > needle removal > branch girdling > base girdling. The old needles were the major source of food for shoot growth and accounted for four-fifths or more of all shoot growth. The combined reserves in the branches, main stem, and roots accounted for less than 15% of shoot growth. The contribution of reserves from tissues other than old leaves was in the following order: branches > main stem > roots. Defoliation weakened apical dominance relations. In defoliated trees, many secondary axes elongated more than the terminal leader, and secondary axes in lower whorls often grew more than those in upper ones. The data suggest an important role of nutritional factors in correlative growth inhibition.     

亚热带植物叶片UV-B吸收化合物的积累

供试的５７种亚热带植物在自然条件下,其叶片ＵＶ－Ｂ吸收化合物在２８０ｎｍ～３３０ｎｍ有１个或２个吸收峰。以单位面积为基数表示的ＵＶ－Ｂ吸收化合物吸收率为乔木＞灌木＞草本;阳生植物＞阴生植物。降低生长光强至自然光的４０％和１６％,荷木,黧蒴,黄果厚壳桂和马尾松叶片的ＵＶ－Ｂ吸收化合物减少８％～４８％。化工厂和电厂附近生长的植物叶片ＵＶ－Ｂ吸收化合物吸收率呈现增高或降低两种变化类型。结果表明叶片具有抵御ＵＶ－Ｂ辐射损伤作用的ＵＶ－Ｂ吸收化合物的积累受植物基因型、生活型、生态型的控制和环境因子的调节。     

OCCURRENCE,TYPE, AND LOCATION OF CALCIUM OXALATE CRYSTALS IN LEAVES AND STEMS OF 16 SPECIES OF POISONOUS PLANTS

Crystals in 16 species of poisonous plants growing naturally in Saudi Arabia were studied with light microscopy. Three types of crystals were observed: druses, prismatics, and crystal sand. Raphides and styloids were not observed in any of the species studied. Druses occur more frequently in the leaf midrib and in the cortex and pith of the stem. In contrast, crystal sand and prismatic crystals are rare and occur in the leaf, intercostal lamina, and in the vascular tissues. The preliminary results show the absence of the three types of calcium oxalate crystals in the stem and leaf of seven species: Ammi majus L., Anagallis arvensis L., Calotropis procera Ait., Citrullus colocynthis (L.) Schard, Euphorbia peplis L., Hyoscyamus muticus L., and Solarium nigrum L., and the presence of druses, prismatic crystals, and crystal sand either in the leaf and stem or in the leaves or stems of nine species: Anabasis articulata (Forssk.) Moq. in DC., Chenopodium album L., Convolvulus arvensis L., Datura stramonium L., Nerium oleander L., Ricinus communis L., Rumex nervosus Vahl., Pergularia tomentosa L., and Withania somnifera (L.) Dun. in DC. These observations indicate that there is no apparent relationship between the distribution of calcium oxalate crystals and the toxic organs of the plants, and supports the view that the presence of calcium oxalate crystals may not be related to plant toxicity.     

千层塔植物茎叶中黄酮类物质的研究

本实验利用分光光度法对千层塔植物茎叶内的黄酮类物质进行了初步测定 ,确定了总黄酮含量提取的适宜溶剂浓度和提取的适宜时间。结果表明 ,用 6 0 %的甲醇溶剂提取 6h总黄酮含量最高。此外 ,本试验还对千层塔黄酮提取液进行了各种定性颜色反应 ,初步确定其中的黄酮类物质主要为黄酮类和黄酮醇类。     

三种鼠尾草注射液对大鼠心肌缺血再灌注损伤的保护作用

本文研究了云南产鼠尾草属药物滇丹参、甘西鼠尾、褐毛甘西鼠尾对急性心肌缺血再灌注损伤的保护作用 ,并与丹参进行对比其疗效的相似性。结扎大鼠冠脉左前降支 ,30分钟后剪断结扎线造成心肌缺血再灌注模型 ,经股静脉给药。测定再灌注 6 0分钟后血清中CK、LDH、SOD、GSH -Px和MDA含量。结果滇丹参、甘西鼠尾、褐毛甘西鼠尾可以显著降低心肌缺血再灌注后血清CK、LDH和MDA含量 ,升高血清SOD和GSH -Px活力 (P <0 0 1,P <0 0 5 ) ,与丹参有相似的抗心肌缺血再灌注损伤作用。     

五种紫萼藓科植物茎及叶的解剖学观察

对紫萼藓科紫萼藓属中的5种植物,运用石蜡切片法和扫描电镜法,对其茎的结构及叶表皮角质层皱褶、孔及纹饰等特征进行观察分析,结果表明：长枝紫萼藓（Grimmia elongata Kaulf.）茎呈多棱形,片状附属物沿叶腹面表皮连成带状,而叶背面角质层纹饰呈辐射状的裂片;圆蒴紫萼藓（Grimmia a pocarpa Hedw.）茎、叶细胞中内含物非常浓厚,细胞不透明,中助的角质层纹饰呈纵向的线状;高山紫萼藓（Grimmia alpicola Sw.ex Hedw.）中肋宽厚,孔呈梯形排列,叶背面角质层皱褶呈“菊花状”纹饰,叶腹面孔口处有“眼皮状”鳞片覆盖;卵叶紫萼藓（Grimmia o-valis(Hedw.)Lindb.）茎无明显的中轴部;中肋“导水细胞”发达,叶表面密布粗疣和网状排列的大孔,且孔深陷;毛尖紫萼藓（Grimmia pilifera P.Beauv.）茎的外皮部和内皮部之间有一层“鞘状”物质,叶背面孔的形状呈挤压状。