CHANGES IN HYDRAULIC CONDUCTIVITY AND ANATOMY CAUSED BY DRYING AND REWETTING ROOTS OF AGAVE DESERTI (AGAVACEAE)

Concurrent determinations of changes in hydraulic conductivity and tissue anatomy were made for roots of Agave deserti excised during drying and following rewetting in soil. At 30 d of drought, hydraulic conductivity had declined less than twofold for older nodal roots, tenfold for young nodal roots, and more than 20-fold for lateral roots (“rain roots” occurring as branches on the nodal roots). These decreases were consistent with increases in cortical lacunae caused by cell shrinkage and collapse. Similarly, reduction of lacunae in response to rewetting after 7 d of drought corresponded to levels of recovery in hydraulic conductivity, with young nodal roots showing full recovery, lateral roots returning to only 21 % of initial conductivity, and older nodal roots changing only slightly. Increases in suberization in the exodermis, endodermis, and cortex adjacent to the endodermis in response to drying coincided with decreases in hydraulic conductivity. Measurements of axial hydraulic conductance per unit length before and after pressurization indicated that embolism caused reductions in axial conductance of 98% for lateral roots, 35% for young nodal roots, and 20% for older nodal roots at 7 d of drought. Embolism, cortical lacunae, and increasing suberization caused hydraulic conductivity to decline during drought in the three root types, thereby helping limit water loss to dry soil; the recovery in hydraulic conductivity for young nodal roots after rewetting would allow them to take up water readily once soil moisture is replenished.     

不同时期毛乌素沙区主要植物种光合作用和蒸腾作用的变化

 采用LI—6000便携式光合分析系统对毛乌素沙区主要植物种油蒿、中间锦鸡儿、旱柳进行了不同时期光合作用,蒸腾作用日进程的测定,并同步测定有效光辐射、空气相对湿度、叶温、气温、胞间CO2浓度、气孔阻力、叶片水势及土壤水势等因子;结果表明：不同时期、不同植物种其光合、蒸腾特征各异;植物的光合、蒸腾与环境因子和植物内部因子之间有密切关系,其中有效光辐射是影响光合作用、蒸腾作用诸因子中的主导因子,而气孔阻力变化则在调节光合和蒸腾中起着重要作用;不同植物种间气孔对环境条件变化的响应程度不同,以中间锦鸡儿最为灵敏;3种植物的水分利用效率表明,中间锦鸡儿的水分利用效率较油蒿、旱柳为高。     

肌细胞发育过程中间隙连接的变化

用石蜡切片、超薄切片和冰冻蚀刻技术研究了东方蝾螈胚胎肌细胞发育过程中间隙连接的变化。间隙连接最初出现于原肠后期的体节中胚层细胞中,到原肠末期,体节中胚层细胞间的间隙连接数量骤增,从神经板期到鼻窝出现期,间隙连接数量保持在一个相当高的水平,肌效应期后,其数量明显下降,直到肌细胞发育成熟,神经-肌肉连接充分发育,间隙连接才消失。间隙连接大小的变化与数量的变化表现为平行的现象。此外,细胞融合之前,正是间隙连接的数量和大小达到最高峰的时间。这些结果说明细胞通讯与胚胎肌细胞发育密切相关。对细胞通讯在细胞决定和分化以及细胞融合中的可能作用进行了讨论。     

土壤水分与温度共同作用对植物根系水分传导的效应

 本文根据不同大气环境温度和土壤温度及不同土壤含水率处理条件下的玉米、向日葵、台湾相思(Acacia confusa)、银合欢(Leucaena glauca)的试验资料，分析了土壤水分和温度以及土壤水分与温度共同作用对植物根系水分传导的效应。台湾相思和银合欢的试验结果表明，在一定的土壤水分范围内，高温(白天/夜晚的温度为40／30℃)环境中的根系水分传导大于低温(30/25℃)环境中的，但当根系水分胁迫十分严重(台湾相思根系水势小于-1.5MPa，银合欢根系水势小于-2.0MPa)时，30/25℃环境的根系水分传导反而大于40／30℃环境的；玉米、向日葵的试验结果表明，在一定土壤温度范围内，根系水分传导随土壤温度增加而增加，其增加的幅度与生育阶段有关；在向日葵生育期土壤温度高于35℃、玉米生育期高于30℃时，其根系水分传导随温度增加而降低。通过植物根区土壤逐渐干旱和干旱复水后的试验，其结果表明复水后根系水分传导上升较快，银合欢复水1.5d、向日葵复水3d后测得的根系水分传导即可达到受旱前的水平，其后的水分传导还略高于一直充分供水处理的，表明根系经受一定程度的干旱锻炼后，对其水分传导具有明显的补偿效应。在干旱和复水过程中根系水分传导与根水势的变化规律相一致。     

CYTOCHEMICAL AND BIOCHEMICAL DETERMINATIONS OF CHANGES IN NUCLEAR HISTONE CONTENT DURING DIFFERENTIATION OF BARLEY ROOT CELLS

Changes in nuclear histone content in barley root cells have been studied by cytochemical methods for identification of histone subtypes and by conjunction with standard biochemical extraction procedure for various histone fractions and alkaline fast green stainability. The results obtained by the cytochemical methods indicate that the nuclear histones in cell nuclei found in their terminal stages of cellular differentiation or elongation contain histones rich in arginine, whereas the nuclei in meristematic cells contain histones rich in lysine. Cytochemicaly intermediate or transitional types of nuclear histones have been observed in cell nuclei which are undergoing differentiation or elongation and in chromosomes of mitotic nuclei. Information obtained from the conjunction of methods of biochemical extraction procedures for various histone fractions and alkaline fast green stainability indicate that the nuclei in well-differentiated cells contain predominantly histones rich in arginine (f3), whereas the nuclei of meristematic cells contain both very lysine-rich histones (f1) and slightly lysine-rich histones (f2). These results suggest the replacement of lysine-rich histones in the nuclei of meristematic cells by arginine-rich histones during cellular differentiation.     

CHANGES IN ORGAN FORMING CAPACITY OF CARROT ROOT CALLUSES DURING SUBCULTURES

1. The formation of buds and roots in seven strains of carrotrootcallus successively cultured for various periods on a mediumcontaining WHITE'S inorganic salts, sucrose, 2,4-D and yeastextract was investigated. 2,4-D completely suppressed organformation during stock subculturing. It was confirmed that theorgan forming capacity of the callus in a 2, 4-D-free test mediumdiminishes and finally completely disappears with prolongedperiods of previous subculturing of the callus.
2. IAA promotedthe root formation. Yeast extract, casein hydrolysateand aminoacids mixture promoted the bud formation of callusesat earlieststeps of subculturing (Phase I).
3. At next steps of subculturing(Phase II), IAA-dependent rootforming capacity of calluseswas lost although the bud formingcapacity induced by yeastextract, casein hydrolysate and aminoacids mixture was retained.
4. At further advanced steps of subculturing (Phase III), yeastextract induced only root formation, while casein hydrolysatestill could induce buds. IAA and amino acids mixture did notaffect the organ formation.
5. No organ formation was observedin calluses subcultured over38 months under any conditionsattempted (Phase IV).
6. Single cells or small cell clumps obtainedfrom the callus subculturedfor 2 months formed only roots onthe medium containing IAAand formed buds and roots on the mediumcontaining yeast extract.
7. These differences in organ formingcapacity and in responsestowards various factors are interpretedto reflect the changesin physiological states of the callusduring successive cultureson the stock culture medium.

(Received December 24, 1964; )     

PHYSIOLOGICAL AND BIOCHEMICAL CHANGES OF CARROT ROOT CALLUS DURING SUCCESSIVE CULTURES

1. The longer the period of stock culture, the more remarkableis the growth inhibition by 8-azaguanine in callus.
2. Chloramphenicol,5-methyltryptophane and mitomycin C exert greaterinhibitionon growth in CCL than in CCS.
3. Bud formation is inhibited bysome concentrations of chloramphenicolwithout accompanyinginhibition of the growth.
4. Cell size and the contents of RNA,DNA, protein and lipid percell of CCL are greater than thoseof CCS, respectively. Thecontents per cell of RNA and lipidin "mitochondrial fraction"are higher in CCL than in CCS.
5. Incorporationof guanine-8-¹⁴C into RNA of CCS occurs rapidlyin the first12 hr and slows down thereafter, but that in CCL-RNAincreasessteadily for 16 hr. This difference in rate of theincorporationafter 12 hr between CCS and CCL is principallydue to the differencein rate of the incorporation into RNAof nuclear, mitochondrialand soluble fractions.

1. The rate of RNA breakdown in CCL wasnot so great as the rateof synthesis.
2. 8-azaguanine (10^–3and 10^–4M) inhibits incorporationof guanine-8.¹⁴C intoRNA of both CCS and CCL during 14 hr,but thereafter (up to25 hr) it inhibits the incorporation intoCCL-RNA alone leavingthat into CCS-RNA unaffected.

1. In CCL 510^–5M 8.azaguaninedoes not affect total radioactivityincorporated into bulk RNA,but inhibits incorporation intoRNA of "mitochondrial fraction".

(Received December 23, 1964; )     

塔克拉玛干沙漠腹地3种植物根系构型及其生境适应策略

 在塔克拉玛干沙漠腹地, 采用挖掘法挖取塔克拉玛干柽柳(Tamarix taklamakanensis)、塔克拉玛干沙拐枣(Calligonum roborovskii)和罗布麻(Apocynum venetum )根系, 对根系的拓扑结构特征进行了测定与分析。结果表明: 1) 3种植物根系均以水平分布占优势, 根系浅层化。2) 3种植物根系结构的适应性不同, 表现为两种不同的根系分支模式, 塔克拉玛干柽柳根系为叉状分支结构(q_a=0.15、q_b=0.09、TI=0.658), 罗布麻(q_a=0.43、q_b=0.35、TI=0. 83)和沙拐枣(q_a=0.52、q_b=0.38、TI=0.86)根系趋向于鱼尾形分支结构。3) 3种植物根系的连接长度都较大, 最小也达1.12 m, 说明在塔克拉玛干沙漠腹地, 3种植物通过增加连接长度来扩大根系在土层中的分布范围, 从而提高根系的有效营养空间, 增加根系连接长度是根系对沙漠腹地贫瘠土壤环境的一个良好适应。4)研究验证了Leonardo da Vinci法则, 即根系分支前的横截面积等于根系分支后的横截面积之和, 3种植物根系分支前后的横截面积符合Leonardo da Vinci法则。研究表明沙漠腹地3种植物根系构型特征既有相似性又有差异性, 在相似的沙漠环境中具有不同的根系适应策略。     

CHANGES IN RESPONSE TO PURINE AND PYRIMIDINE DERIVATIVES OF CARROT ROOT CALLUS DURING SUCCESSIVE CULTURING

1. The growth of the carrot root callus which had been subculturedfor a long period (CCL) was promoted by the addition of 5l0^–8and 5l0^–7 M kinetin, whereas in the callus subculturedfor a short period (CCS) no growth promotion was observed atany concentrations of kinetin tested.
2. CCL showed an increasedgrowth in response to the applicationof kinetin, guanine, adenine,hypoxanthine, uracil, thymine,and cytosine in the presenceof fractions A and C of carrotroot extract, whereas no suchresponse was observed in CCS.CCL required fraction C to respondto uracil and probably purineand pyrimidine derivatives ingeneral.
3. The growth of CCL was promoted by kinetin, guanine,adenine,or hypoxanthine in the medium containing inositol andaminoacids mixture. In this case the growth-promoting actionof guanine,adenine, or hypoxanthine was nullified by kinetin.

(Received December 24, 1964; )     

大鼠内毒素血症不同时期血浆CGRP和背根神经节CGRP mRNA水平的变化

本文采用逆转录聚合酶链反应（RT－PCR）方法测定大鼠内毒素血症不同时期胸腰段背根神经节降钙素基因相关肽（CGRP）mRNA水平的改变,结合血浆CGRP水平的改变,以期全面了解大鼠内毒素血症不同时期CGRP释放与合成的变化。结果显示：注射内毒素（5mg／kg）后30min时,大鼠血浆CGRP开始增高,而背根神经节CGRPmRNA水平无明显变化;注射内毒素后3h时,血浆CGRP及背根神经节CGRPmRNA均明显增高．分别为142％和32％,8h时则进一步增高,分别为216％和85％。提示内毒素不仅刺激外周组织释放CGRP,而且还能通过某些机制激活背根神经节CGRPmRNA的转录,使CGRP合成增加,以作为CGRP大量释放的重要补充来源。     

石刁柏愈伤组织根和芽分化过程中POD和SOD活性的变化

研究了石刁柏愈伤组织根和芽分化过程中可溶性蛋白质含量,过氧化物酶（ＰＯＤ）,超氧物岐化酶（ＳＯＤ）和非特异性酯酶（ＮＳＥ）活性变化的规律,结果表明：（１）在根和芽分化过程,可溶性蛋白质量增加,第８～１０ｄ增至高峰时,分别为愈伤组织的１．９８倍（根）和２．１９倍（芽）,随着根和芽进一步生长,可溶性蛋白质含量下陈,（２）在根（第１０ｄ）和芽（第８ｄ）形成时,ＰＯＤ活性达到最高水平,分别为１．９２和２．     

云南哀牢山6种常绿阔叶树木质部解剖特征的轴向和径向变化

West、Brown和Enquist提出的树木水分传导的分形网络模型(简称WBE模型)认为,树木连续分枝之间的导管或管胞直径按照一定的比率均匀变细,其总的水力阻力与水分传导的路径长度无关,从而使不同部位叶片获得基本相当的水分供应。该模型对树木高生长的水力限制假说提出了置疑。为了验证WBE模型中树木导管或管胞均匀变细的假说,该文研究了云南哀牢山中湿性常绿阔叶林中6种常绿阔叶树, 腾冲栲(Castanopsis wattii)、景东石砾(Lithocarpus chintungensis)、木果石砾(L. xylocarpus)、长尾青冈(Cyclobalanopsis stewardiana)、滇木荷(Schima noronhae)和舟柄茶(Hartia sinensis)木质部解剖特征随树高和年龄的变化。对这6个树种共14株样木进行了不同高度树干圆盘和边材生长轮取样,样木的高度为15~25 m,按照常规木材解剖的处理和分析方法,在显微镜下测定木材切片的导管直径和密度等特征。结果表明:在14株样木中,有4株树木导管直径随树木高度增加呈线性减小, 1株没有明显变化,其它9株树木导管直径在树冠以下的树干部分变化幅度较小或没有明显变化,而从树冠基部往上直到树木顶端导管直径显著减小。同一植株随着高度的增加,导管密度增加并且在树冠内增加更显著。有三分之一的树木导管占边材面积的比例随树高增加没有明显变化,其余树木导管占边材面积比在树冠以上有所减小。多数树木理论比导率在树冠以下没有明显变化而在树冠基部往上显著降低。在从髓芯开始往外的20~40个年轮范围内导管直径增加显著,但大部分植株导管直径在40个年轮后趋于稳定。不同高度圆盘导管直径随形成层发育时间的变化呈相似的趋势,并且相同发育年龄的导管直径没有明显差异。该文的研究结果说明,导管直径的轴向和径向变化一定程度上补偿了水分运输阻力随树木个体增大而增加的缺陷,但是6种常绿阔叶树树干的导管基本不按一定比率均匀变细,不支持WBE模型。     

上皮细胞分裂过程中中等纤维的变化

应用制备的血清抗体,采用免疫细胞化学方法观察了两株培养上皮细胞的分裂过程中IF的动态变化过程。实验结果显示,在上皮细胞分裂过程中,IF形态结构及空间分布发生了显著变化,不同细胞之间存在差异,分裂的Vero细胞中角蛋白纤维和波形纤维都维持纤维形态,围绕分裂器形成纤维网罩或纤维束环,随着细胞分裂的进行,IF网的空间组织结构和外观发生动态变化;分裂的HeLa细胞中,角蛋白纤维和波形纤维广泛重组形成颗粒状胞质小体,分裂结束后重建IF网。实验结果表明,IF变化具有细胞周期依赖性和一定的细胞特异性。本文对IF在细胞分裂过程中的功能意义作了讨论。     

CHANGES IN THE DISTRIBUTION OF A HISTONE IN DORSAL ROOT GANGLION NEURONS DURING DEVELOPMENT

The isolation and cellular localization of a basic protein (histone) from central nervous tissue have been previously reported. In the tissues previously studied (nervous tissue, testis, liver, spleen, kidney, ovary), the basic protein was restricted in distribution to the nuclei of neurons and spermatogonia. In the present study, the temporal appearance of the histone within neurons and the changes in its distribution during ontogenesis were examined. The reaction between a fluorescent immune γ-globulin prepared against this purified tissue-specific histone and the neurons from the dorsal root ganglia of the rat was investigated. The dorsal root ganglia examined were those from fetuses, 2-, 10-, and 40-day-old rats, and from adult rats. At the earliest stages, only the nucleoli reacted. Subsequently, threads of fluorescent material were seen to emerge from the nucleoli. The extent of this reaction between the immune globulin and the threads within the nuclei continued to increase with maturation. No changes in fluorescence localization during development could be seen in the nuclei of neurons in the cerebellum or brain stem. The role that this tissue-specific histone may play in cell function is discussed.     

森林降水酸度及电导率的时空变化

在离大气污染源距离不同的两片杉木(Cunninghamia lanceolata)人工林中建立监测场,对降水化学进行了为期3年(1994～1996)的定位监测。降水通过林冠截留后,其酸度和电导率均明显增加,尤以树干径流为显著。在 FFC监测场,降雨、穿透雨和树干径流雨量加权平均pH值分别为6.13、6.06和4.18,在XQF监测场,其相应的数值分别为5.86、5.67和3.37;降雨和穿透雨的酸度表现出一定的季节变化动态,其最低月均pH值出现在夏委,最高值在冬季。在FFC监测场,降雨、穿透雨和树干径流雨量加权平均EC值分别为28.51μs·cm-1、63.71μs·cm-1、240.85μs·cm-1,在XQF监测场,其相应的数值分别为36.99μs·cm-1、66.41μs·cm-1、501.85μs·cm-1：降水电导率表现出显著一致的季节变化格局,其月均值均以夏季最低,冬季最高,春秋季居中,这种格局强烈受降雨量的影响。离污染源较近的XQF监测场,降水酸度和电导率明显高于相对未受污染的FFC监测场。     

CHANGES IN THE RESPONSE OF CARROT ROOT CALLUSES TO THE ROOT EXTRACT OCCURRING DURING THEIR SUCCESSIVE CULTURES

1. Alcohol extract of carrot root promoted the growth of the carrotroot callus which had been succesively cultured for more than18 months (CCL) on the medium containing WHITE'S inorganic salts,sucrose, yeast extract and 2, 4-D, but only a weak promotionwas observed for the growth of the carrot root callus whichhad been cultured for less than 14 months (CCS).
2. The activesubstances were fractionated by Amberlite IR-120and AmberliteIRA-400 into four fractions; C, D, E, and F. Eachfraction seemedto act synergistically to produce the effectof the whole carrotroot extract on the growth of CCL.
3. Fraction F of the carrotroot extract, which was adsorbed byAmberlite IRA-400 but notby Amberlite IR-120, promoted thegrowth of CCL in the presenceof other fractions, but had noeffect on the growth of CCS.So the different responses to thealcohol extract of the carrotroot calluses having differentlengths of successive cultureperiod seemed to depend mainlyon the ability of respondingto fraction F.
4. Using four strains of carrot root callusesof different origin,it was ascertained that different responsesof carrot root callusesto fraction F depended on the lengthof their culture and noton their strain-specific characters.
5. The substances active for the growth of CCL in the carrotrootextract passed through a dialysis membrane. These substanceswere little affected by autoclaving and remained in the aqueouslayer when shaken with several organic solvents: n-butanol,ethyl acetate, chloroform, benzene, ethyl ether and carbon tetrachloride.
6. Alcohol extract of carrot root also promoted the growth ofcarrotroot explant, tobacco stem callus and sunflower crowngall tissue.

(Received December 24, 1964; )     

长江刀鲚生殖洄游期间脂肪酸组成及含量变化分析

为探究长江刀鲚生殖洄游过程中脂肪酸组成及其含量变化规律,研究选择洄游距离、卵巢发育和规格大小3个影响因子设置梯度,对长江刀鲚肝胰腺、肌肉和卵巢的脂肪酸组成及含量进行实验分析。实验结果显示, 62尾雌性刀鲚3个组织均检测出28种脂肪酸,以单不饱和脂肪酸(MUFA)含量最高,大于各组织总脂肪酸含量的56.23%,各类脂肪酸中的C18:1、C16:0、C16:1、DHA和EPA含量较高,为主要脂肪酸。在生殖洄游过程中,刀鲚肝胰腺总脂肪含量随洄游距离的延长呈上升趋势,从崇明江段的(526.61±38.50) mg/g增加至安庆江段的(587.21±124.72) mg/g,而肌肉和卵巢总脂肪酸含量呈显著下降趋势,分别下降了33.03%和57.09%(P<0.05)。在各体长组中,肌肉总脂肪酸、SFA、MUFA和PUFA含量与体长呈正相关(P<0.05),而肝胰腺和卵巢总脂肪酸及各类脂肪酸含量与体长无显著相关性(P>0.05)。在卵巢发育过程中,刀鲚肝胰腺和肌肉总脂肪酸、MUFA和PUFA含量随卵巢由Ⅱ期发育至Ⅳ期均呈下降趋势,总脂肪酸含量分别减少了47.56%和22.40%,...     

白花泡桐不定根发生过程中内源激素和RNA的变化

白花泡桐（Ｐａｕｌｏｗｎｉａｆｏｒｔｕｎｅｉ（Ｓｅｅｍ．）Ｈｅｍｓｌ．）成年型和幼年型茎切段体外培养时不定根发生过程中内源ＩＡＡ、ＣＴＫ和ＡＢＡ含量测定表明：幼年型材料中内源ＩＡＡ和ＣＴＫ的含量在诱导的第２天同时达到高峰,而成年型材料中ＩＡＡ和ＣＴＫ含量的高峰则在第４天出现．两种类型切段根原基出现的时间都与其内源ＩＡＡ和ＣＴＫ的高峰一致．幼年型材料的内源ＡＢＡ含量在第４天达到高峰,随后迅速下降．成年型材料中内源ＡＢＡ则逐步下降．成年型和幼年型材料中ＲＮＡ的变化相同,在诱导的第２天稍有下降,随后显著增加．结果显示,不定根的发生与其内源激素和ＲＮＡ的变化密切相关．     

两种沙生植物内源激素,叶绿体膜脂肪酸组成和膜脂抗氧化系统 …

对两种生长于相同沙丘生境中植物的内源生长调节物质,叶绿体膜脂肪酸组成及膜脂抗氧化系统酶类的季节变化的研究,结果证明：具有极强耐旱性的泡泡刺比具较强耐旱性的沙拐枣体内脱落酸（ＡＢＡ）含量量４．７倍（５月）和３．５倍（７月）。而两种植物的ＡＢＡ含量高峰出现在７月,可能是受发育及环境的高温的影响。玉米素核苷（ＺＲｓ）的季节变化与植脂的不饱和脂肪酸指数（ＩＵＦＡ）较高,而７月由亚麻酸、亚油酸含量下降,棕榈