三峡大老岭山地常绿落叶阔叶混交林林隙干扰研究 I．林隙基本特征

为探讨我国亚热带山地常绿落叶阔叶混交林的林隙干扰特征,对三峡大老岭地区这一植被类型进行调查,分析了植被中林隙的数量、类型及成因;林隙形成木（GM）的类型、数量、物种构成和径级结构,以及林隙和GM的多尺度空间格局特征。结果表明1）林隙密度为11.7个*hm-2;冠林隙和扩展林隙分别占森林面积的11.09%和27.06%。平均每个林窗的形成木为4.5株;单株GM形成的林隙只占17.46%,其中翻倒木集群性最强。对林隙形成的贡献大小次序是翻倒木>折干>枯立>折枝。2）林隙成因方面冬雪和春、秋冻雨的影响最大;病害影响其次;树木间的牵连和撞击扩大了林隙的范围;陡峭的地形增大林隙形成的机率;干旱的影响很小。3）68种GM主要是森林建群种;常绿树种形成林隙的平均机率高于落叶种。4）GM的胸径结构表明本地森林林隙干扰十分频繁。     

三峡大老岭山地常绿落叶阔叶混交林林隙干扰研究II.林隙干扰的地形格局

 根据对三峡大老岭地区山地常绿落叶阔叶林林隙的调查结果,运用多种方法定量分析和检验了5种地形要素对林隙和3类林隙形成木(GM)各方面特征的空间格局的影响。结果反映了地形对林隙时空格局的影响,和不同类型林隙形成木的响应特征：1）林隙干扰随海拔上升、坡度增大、坡位从山脊到沟谷、坡形由凸到凹而加剧;坡向影响的规律不明显。林隙特征对各地形因素梯度有显著的响应,其中扩展林隙面积、林隙高度、GM数量、种数以及平均胸径是反映地形影响的敏感指标。2）GM的平均胸径、最大胸径和扩展林隙面积与海拔显著正相关;GM平均胸径还与坡位正相关;GM数量沿N→S的坡向梯度减少,而随坡度增大及坡形由凹转凸而增加;GM种类沿坡度和坡形梯度有相同的变化趋势。林隙高度（亦即植被高度）随海拔和坡度增大而减小,但随坡位上升而增大。地形要素对林隙高度和GM平均胸径的空间格局的贡献最大,分别达到75.9%和67.0%。3）折干特征的空间格局受海拔和坡位的显著影响;枯立木的分布特征主要受小地形的坡位和坡形控制;影响翻倒木的最根本地形因素是坡度。     

三峡大老岭山地常绿落叶阔叶混交林林隙干扰研究II.林隙干扰的地形格局

根据对三峡大老岭地区山地常绿落叶阔叶林林隙的调查结果,运用多种方法定量分析和检验了5种地形要素对林隙和3类林隙形成木(GM)各方面特征的空间格局的影响。结果反映了地形对林隙时空格局的影响,和不同类型林隙形成木的响应特征：1）林隙干扰随海拔上升、坡度增大、坡位从山脊到沟谷、坡形由凸到凹而加剧;坡向影响的规律不明显。林隙特征对各地形因素梯度有显著的响应,其中扩展林隙面积、林隙高度、GM数量、种数以及平均胸径是反映地形影响的敏感指标。2）GM的平均胸径、最大胸径和扩展林隙面积与海拔显著正相关;GM平均胸径还与坡位正相关;GM数量沿N→S的坡向梯度减少,而随坡度增大及坡形由凹转凸而增加;GM种类沿坡度和坡形梯度有相同的变化趋势。林隙高度（亦即植被高度）随海拔和坡度增大而减小,但随坡位上升而增大。地形要素对林隙高度和GM平均胸径的空间格局的贡献最大,分别达到75.9%和67.0%。3）折干特征的空间格局受海拔和坡位的显著影响;枯立木的分布特征主要受小地形的坡位和坡形控制;影响翻倒木的最根本地形因素是坡度。     

卧龙自然保护区亚高山暗针叶林林隙特征研究

以卧龙亚高山暗针叶林为研究对象,分析了森林群落林隙的大小结构、形成方式及林隙形成木(GM)的结构特征．结果表明,林隙密度为18．5个·hm^-2冠林隙和扩展林隙分别占森林面积的28．4％和60．0％;冠林隙的大小变化在10～1134．7m^2之间,平均面积为153．45m^2;扩展林隙的大小变化在84．11～1646．3m^2之间,平均面积为324．34m^2;平均每个林隙的形成木为5．14株,单株形成木形成的林隙只占8．1％．不同形成木类型对林隙形成的贡献大小次序为：折干>掘根>枯立>断梢;暗针叶林林隙大多由岷江冷杉、铁杉、糙皮桦形成．径级在60～70cm,高度在30～35m之间的林冠上层的岷江冷杉,发生折倒形成林隙的可能性最大．     

卧龙自然保护区林隙干扰特征

 林隙干扰对森林的结构和多样性的维持具有重要意义。对五一棚周围林隙干扰格局和林隙特征进行了3条样线调查,样线总长度为4.4 km。结果表明：1)本区以小型林隙干扰为主,林隙平均密度为12.5个•km-1,林隙的分布格局在阳坡和山脊为集聚分布,阴坡近均匀分布;林隙形成木以针叶树为主,岷江冷杉(Abies faxoniana)、铁杉(Tsuga chinensis)和糙皮桦(Betula utilis)在形成木的数量和径级组成上均居前列。2)林隙形成木的腐烂等级分布揭示出林隙形成木的形成方式和种类组成均随时间变化。表现为针叶树组形成木对林隙的贡献随时间降低,阔叶树组反之;砍伐和倒木是早期林隙形成的主要方式,而枯立和折干是近期林隙形成的主要方式。3)林隙木形成方式关联度分析结果为砍伐与倒木、折干与倒木之间存在显著负关联,林隙其它各形成方式之间的关联不显著,但砍伐与其它形成方式的负联结系数均较高。     

中亚热带常绿阔叶林林隙及其自然干扰特征的研究

通过对福建万木林中亚热带常绿阔叶林中96个林隙的调查,研究了中亚热带常绿阔叶林的基本特征和自然干扰规律,结果表明,在中亚热带常绿阔叶林中,扩展林隙(EG)和冠空隙(CG)在中亚热带常绿阔叶林景观中的面积比例分别为50．86％和16．66％,每年干扰频率分别为0．85％·年^-1和0．28％·年^-1,林隙干扰的返回间隔期约为357年．林隙形成方式由树木折干形成的最为普遍,占形成木总数58．04％。其次是由于掘根风倒而形成的,占33．48％．林隙大多由两株树木形成,平均每个林隙拥有形成木2．33株．扩展林隙的大小多在100～300m^2之间,其中以200～300m^2者所占的面积比例最大,而以100～200m^2者所占的数量比例最大,冠空隙的大小多在100m^2以下,其中50m^2以下所占的数量比例和面积比例都是最大的．林隙形成木分布最多的径级在20～30cm之间。     

藏东南亚高山冷杉林林隙特征与干扰状况研究

从林隙的大小结构、干扰频率、形成方式及林隙内形成木的数量特征等几个方面,对藏东南色季拉山亚高冷杉林的典型群落类型－－藓类冷杉林的林隙干扰关况进行了分析。结果表明,在冷杉林中,扩展林隙（EG）和冠空隙（CG）的面积分别占林分总面积的41．73％和14．71％;平均每年有0．82％的林分面积转化为扩展林隙,0．29％的林分面积转化为冠空隙;每年1hm^2面积上约有0．31个林隙形成;林隙的干扰周期为345年,在调查的16个林隙中,共有形成木（GM）78株,平均每个林隙中有4．88株,形成林隙最主要的方式是形成木的折倒,其次为根和枯立,主要外力作用是风,当主林层林木直径达到40－60cm、高度15－20m时,形成林隙的可能性最大;同一林隙常常受到形成木多种死亡方式的影响,且形成时期各不相同,藏东南亚高山杉林林由不同年代的多次干扰而形成。     

塔里木荒漠河岸林干扰状况与林隙特征

对塔里木河中游荒漠河岸林林隙基本特征和干扰状况进行了研究。结果表明：形成的林隙形状近似于椭圆形,椭圆长短轴比率在扩展林隙(EG)和冠空隙(CG)有所不同,平均分别为1.52和2.31;林隙密度约为62.5个?hm-2, EG和CG在塔里木荒漠河岸林景观中的面积比例分别为69.52%和29.03%,干扰频率分别为1.45%?a-1和0.61%?a-1,林隙干扰返回间隔期约为164a。林隙大小结构表现出以小林隙为主的偏正态分布,EG大小40—200m2,CG大小0—80m2。林隙形成速率为1.30个?hm-2a-1,20—30a前形成的林隙最多。林隙形成方式由树木折干 枯立形成的最为普遍,占形成木总数95.73%。林隙大多由2—5株形成木形成, 而由4株形成木创造的林隙最多,平均每个林隙拥有形成木4.1株。林隙形成木主要为森林建群种,林隙形成木分布最多的径级在5—25cm,高度在4—8m,每株形成木所能形成的EG面积为27.12m2, CG面积为11.32m2。边缘木的径级结构呈正态分布,而高度结构呈偏左的正态分布,平均每个林隙拥有8.375株边缘木,林隙边缘木平均胸径比形成木平均胸径高73.1%,表明荒漠河岸林林隙干扰十分频繁,地下水位的持续下降是林隙形成的驱动力。     

蛟河阔叶红松林林冠干扰及林隙更新研究

研究了吉林蛟河实验林场阔叶红松林的林冠干扰状况及林隙更新的基本规律。结果表明,扩展林隙（ＥＧ）和冠空隙（ＣＧ）在阔叶红松林中所占的面积比例分别是１８．０９％和１２．５１％,林冠干扰的返回间隔期为７００ａ左右;ＣＧ的大小平均为ＥＧ的６９％,ＥＧ的面积变化在１７—２８４ｍ２之间,平均为７５．４９ｍ２,而ＣＧ的面积变化在１０—２３４ｍ２之间,平均为５１．９８ｍ２,大多数林隙的平均直径仅为主林层树高的２０—６０％;大多数的林隙是由单株形成木形成的,形成林隙最重的方式是干基折断和掘根风倒;林隙形成木主要是由红松、沙松、枫桦和鱼鳞松四个树种组成,林隙形成木的胸径大都在４０—８０ｃｍ之间,树高在２５—３０ｍ之间;林隙的空间分布格局是均匀型的。不同树种在林隙内外的数量特征不同,随着林隙与非林隙的交替变化,不同树种的优势地位亦发生相应的变化,根据不同树种在林隙内外重要值位序差值的大小,可将蛟河阔叶红松林内树种对林隙的更新反应划分为三种类型。林隙及非林隙林分的物种多样性特征不同     

川西亚高山针叶林林窗特征的研究

为探讨川西亚高山针叶林的林窗干扰特征 ,对王朗自然保护区的这一植被类型进行了调查 ,分析了该类型森林中林窗的数量、大小、形状及其成因 ;林窗形成木 (GM )的类型、数量和物种构成。结果表明 ,在川西亚高山原始针叶林林区 ,大多数形成木都是因树木达到一定年龄后衰老等原因引起其抗性下降而死亡的 ;由树木基折形成的林窗最为普遍 ,占 5 1 2 3% ,由干折形成的占 2 0 37% ;单株形成木林窗几乎达到所调查林窗的一半 (占总数的 4 6 99% ) ,平均每个林窗拥有 1 95株形成木。扩展林窗大小多在 10 0～ 4 0 0m2 ,10 0～ 2 0 0m2 所占的数量比例最大 ,占 2 6 5 1% ;而 30 0～ 4 0 0m2 所占的面积比例则最大 ,占 2 2 6 4 %。冠空隙的面积多在 2 0 0m2 以下 ,其中以 5 0～ 10 0m2 所占的数量比例和面积比例均为最大 ,分别为 32 5 3%、17 72 %。冠空隙、扩展林窗的平均面积为 71 6 8m2 、15 4 14m2 。     

Micturition-suppressing region in the periaqueductal gray of the mesencephalon of the cat

The periaqueductal gray (PAG) of the mesencephalon has been implicated to be involved in the control of micturition. We investigated the micturition-suppressing region in the PAG of the cat. Decerebrated 27 adult cats were used. A microelectrode was inserted stereotaxically into the PAG, and a region was searched where electrical stimulation suppressed isovolumetric bladder contractions. Simultaneous stimulation of the pontine micturition center (PMC) and micturition-suppressing region in the PAG was performed before and after an injection of bicuculline (GABA(A) blocker) into the PMC. The micturition-suppressing region was found at the dorsolateral margin of the rostral PAG. Bladder contractions were not provoked by simultaneous stimulation of the PMC and micturition-suppressing region in the PAG. However, after bicuculline injection into the PMC, partial bladder contractions were provoked by simultaneous stimulation of the PMC and the micturition-suppressing region in the PAG. These results suggest that the dorsolateral margin of the rostral PAG includes the micturition-suppressing region that seems to have neural connections with the PMC. GABA is assumed to be one of the neurotransmitters that are involved in the PMC inhibition from the micturition-suppressing region in the PAG.     

Endo's stress analysis of the primate skull and the functional significance of the supraorbital region

A review of Endo's experimental and theoretical procedures and data indicates that the magnitude of the principal strains in the glabella region of both humans and gorillas are low as compared to other parts of the face. Therefore, his data do not provide support for the hypothesis that the glabella region is a highly stressed region during biting. In addition, increased levels of strain in the supraorbital region are directly related to increased levels of masticatory muscle and reaction forces, and not necessarily to anterior tooth loading as opposed to posterior tooth loading. His data also indicate that the supraorbital region in extant humans cannot be accurately modeled as a beam. These conclusions either differ from those of Endo or are not clearly presented or emphasized throughout any of Endo's papers. Therefore, we suggest that a number of investigators have made unsupported or erroneous conclusions based on Endo's work. This is particularly true for those studies that have emphasized the existence of powerful bending stress in the glabella region during incisor biting in both humans and non-human primates.     

Sequencing of selected regions of the human immunoglobulin heavy-chain gene locus that completes the sequence from JH through the delta constant region.

Much of the nucleotide sequence between the start of the joining region and the end of the immunoglobulin heavy chain delta gene has already been determined. However, two gaps existed in potentially functionally important regions in this sequence: the region between the 3' end of the joining region and the heavy chain enhancer region and that between the enhancer and the mu constant region. We have determined the nucleotide sequences of these regions. The 734 bp between the joining and enhancer regions contained no additional joining regions. The 4525 bp region between the heavy chain enhancer and the mu constant region contains the mu switch region, which consists of pentameric repeats. Approximately 60% of these repeats are GGGCT and GAGCT. With the determination of these sequences, the entire region of the heavy chain locus starting upstream of the joining region to downstream of the last exon of the delta constant region (a total of more than 29 kb) has now been sequenced.     

Nucleotide sequence of the promoter region of the melibiose operon of Escherichia coli

The nucleotide sequence of the promoter region of the melibiose operon of E. coli was determined. Consensus sequences for the -35 region, the Pribnow box and the binding site for cyclic AMP receptor protein were found in this region. The possible secondary structure of this DNA region was very similar to that of the promoter region of the lactose operon. A possible initiation ATG preceded by a Shine-Dalgarno sequence with proper spacing was present just downstream of the promoter region. The possible sequence of 52 amino acid residues in the NH2 terminus of the alpha-galactosidase were determined.     

The involucrin gene of the gibbon: the middle region shared by the hominoids

The evolution of the anthropoid involucrin gene has resulted largely from a process of vectorial addition of short tandem repeats. The coding region of the involucrin gene of the gibbon (Hylobates lar), including the segment of repeats, has been cloned and sequenced, and its repeat structure can now be compared with that of the other hominoids. In the gibbon, as in the others, repeat additions in the past can be assigned to early, middle, and late regions of the present-day segment of repeats. All 10 repeats of the gibbon early region were completed in a common anthropoid ancestor. All 17 repeats of the gibbon middle region were completed in a common hominoid ancestor. After divergence of the gibbon lineage, eight repeats were added to the middle region of the great ape-human lineages. Seven of these are shared by two to four species, according to the order of their divergences from each other. After its divergence, the gibbon lineage added a short species-specific late region. The gibbon also possesses an incomplete repeat just 3' of the early region, the only addition in this region in any hominoid. Comparison of the number of repeats added with the number of nucleotides substituted shows an inconstant relation between the two.     

Identification of the region in Cdc42 that confers the binding specificity to activated Cdc42-associated kinase

The Rho family small G-protein Cdc42 has been implicated in a diversity of biological functions. Multiple downstream effectors have been identified. How Cdc42 discriminates the interaction with its multiple downstream effectors is not known. Activated Cdc42-associated tyrosine kinase (ACK) is a very specific effector of Cdc42. To delineate the Cdc42 signaling pathway mediated by ACK, we set about to identify the specific ACK-binding region in Cdc42. We utilized TC10, another member of the Rho family of G-proteins that is 66.7% identical to Cdc42, to construct TC10/Cdc42 chimeras for screening the specific ACK-binding region in Cdc42. A region between switch I and switch II has been identified as the specific ACK-binding (AB) region. The replacement of the AB region with the corresponding region in TC10 resulted in the complete loss of ACK-binding ability but did not affect the binding to WASP, suggesting that the AB region confers the binding specificity to ACK. On the other hand, replacement of the corresponding region of TC10 with the AB region enabled TC10 to acquire ACK-binding ability. Eight residues are different between the AB region and the corresponding region of TC10. The mutational analysis indicated that all eight residues contribute to the binding to ACK2. The assays for the Cdc42-mediated activation of ACK2 indicated that the AB region is essential for Cdc42 to activate ACK2 in cells. Thus, our studies have defined a specific ACK-binding region in Cdc42 and have provided a molecular basis for generating ACK binding-defective mutants of Cdc42 to delineate ACK-mediated signaling pathway.     

Studies on the Early Development of the Eugregarine Gregarina garnhami

SYNOPSIS. The Eugregarine Gregarina garnhami is parasitic in the mid-intestine and caecae of the desert locust Schistocerra gregaria (Forsk). The penetration oi the sporozoite and its development into a three-segmented cephalont is described. At no time in its development is the Fregarine completely intracellular; the so-called intracellular stages of other workers are shown to be the breakdoan products of the intestinal host cells themselves.
After penetrating the host intestinal cell the sporozoite grows rapidly and the anterior intracellular region outgrows the posterior estracellular region. Once the intracellular region reaches a size 13–16 μ in diameter. growth oi this region ceases and growth is now concentrated in the posterior region. When this latter region has reached 20 μ in diameter an annulus appears. This, by growing diametrically across the posterior epimerite region, divides the extracellular region into protomerite and deutomerite.
Detachment of the cephalont is considered to be a passive and not an active process and is dependent on the breakdown and extrusion of host cells. In this process the epimerite may or may not become detached from the protomerite.
A system of lonpitudinal fibres (myonemes) exists within the protomerite, and these play an important role in converting the protomerite into an adhesil-e disc prior to conjugation.
Extensive folding of the epicyte occurs in both the protomerite and deutomerite in the three-segmented cephalont; this folding could not be observed prior to the division of the gregarine into three regions. The epimerite has a dual function in the early stages of development, serving both as an attachment organelle and as an absorptive region across which iood materials may pass from the host cell.     

The involucrin gene of the orangutan: generation of the late region as an evolutionary trend in the hominoids

In the evolutionary line leading to the higher primates, the coding region of the involucrin gene evolved a segment consisting of numerous repeats of a 10-codon sequence. Additions to this segment of repeats have been made successively, thus generating regions that can be defined as early, middle, and late. The involucrin gene of the orangutan (Pongo pygmaeus abelii) possesses a segment of repeats whose early region has the same repeat structure as that in other anthropoids. The middle region is not similar in repeat structure to that of all anthropoids but is similar to that of other hominoids. The late region is unique to the species; it does not correspond at all in its repeat structure to that of the human or gorilla and is much larger. The late region of the orangutan was generated by duplications of blocks of older repeats clearly belonging to the middle region. Continued duplications extending the late region are an evolutionary trend in the hominoids. The process of addition of repeats at a particular location is a more significant aspect of the evolution of involucrin than are random nucleotide substitutions; in addition, it has proceeded more rapidly.      

Functional analysis of the C-terminal region of the vacuolar cadmium-transporting rice OsHMA3

Rice OsHMA3 is a vacuolar cadmium (Cd) transporter belonging to the P_1B-ATPase family and has a long (273aa) C-terminal region. We analyzed the function of the region related to Cd using the transgenic Arabidopsis Col-0 ecotype, which is sensitive to Cd. The OsHMA3 variant containing a truncated (58aa) C-terminal region did not confer Cd tolerance, whereas an OsHMA3 variant containing a longer truncated (105aa) C-terminal region conferred Cd tolerance to transgenic Arabidopsis. We conclude that the C-terminal region, particularly the region containing the first 105aa, has an important role in OsHMA3 activity.