Effect of Light Irradiation on the D-Alanylglycine Content in Rice Leaf Blades

(1) The fluctuating pattern of D-alanylglycine content, althoughthe increase and decrease rates were not very high, in the leafblades of rice seedlings growing in light or dark was relatedto that of the chlorophyll content in the leaf blades. (2) TheD-alanylglycine content in the leaf blades of the chlorophyll-lesscultivar was lower than that of the normal one. (3) Photosyntheticallyassimilated carbon was smoothly incorporated into D-alanylglycine.(4) Exogenous D-alanine was only incorporated into D-alanylglycinewhen the D-alanine feeding was performed under light. Theseresults suggested that D-alanylglycine synthesis in the leafblades of rice plants is closely related to the amino acid metabolismaccompanying photosynthesis in rice plants. (Received March 19, 1983; Accepted June 29, 1983)     

Development of monosomic alien addition lines and introgression of genes from Oryza australiensis Domin. to cultivated rice O. sativa L.

Oryza australiensis, a diploid wild relative of cultivated rice, is an important source of resistance to brown planthopper (BPH) and bacterial blight (BB). Interspecific hybrids between three breeding lines of O. sativa (2n=24, AA) and four accessions of O. australiensis (2n=24, EE) were obtained through embryo rescue. The crossability ranged from 0.25% to 0.90%. The mean frequency of bivalents at diakinesis/metaphase I in F₁ hybrids (AE) was 2.29 to 4.85 with a range of 0–8 bivalents. F₁ hybrids were completely male sterile. We did not obtain any BC₁ progenies even after pollinating 20,234 spikelets of AE hybrids with O. sativa pollen. We crossed the artificially induced autotetraploid of an elite breeding line (IR31917-45-3-2) with O. australiensis (Acc. 100882) and, following embryo rescue, produced six F₁ hybrid plants (AAE). These triploid hybrids were backcrossed to O. sativa. The chromosome number of 16 BC₁ plants varied from 28 to 31, and all were male sterile. BC₂ plants had 24–28 chromosomes. Eight monosomic alien addition lines (MAALs) having a 2n chromosome complement of O. sativa and one chromosome of O. australiensis were selected from the BC₂ F₂ progenies. The MAALs resembled the primary trisomies of O. sativa in morphology, and on the basis of this morphological similarity the MAALs were designated as MAAL-1, -4, -5, -7, -9, -10, -11, and -12. The identity of the alien chromosome was verified at the pachytene stage of meiosis. The alien chromosomes paired with the homoeologous pairs to form trivalents at a frequency of 13.2% to 24.0% at diakinesis and 7.5% to 18.5% at metaphase I. The female transmission rates of alien chromosomes varied from 4.2% to 37.2%, whereas three of the eight MAALs transmitted the alien chromosome through the male gametes. BC₂ progenies consisting of disomic and aneuploid plants were examined for the presence of O. australiensis traits. Alien introgression was detected for morphological traits, such as long awns, earliness, and Amp-3 and Est-2 allozymes. Of the 600 BC₂ F₄ progenies 4 were resistant to BPH and 1 to race 6 of BB. F₃ segregation data suggest that earliness is a recessive trait and that BPH resistance is monogenic recessive in two of the four lines but controlled by a dominant gene in the other two lines.     

Cloning and characterization of repetitive DNA sequences from genomes of Oryza minuta and Oryza australiensis

The value of genome-specific repetitive DNA sequences for use as molecular markers in studying genome differentiation was investigated. Five repetitive DNA sequences from wild species of rice were cloned. Four of the clones, pOm1, pOm4, pOmA536, and pOmPB10, were isolated from Oryza minuta accession 101141 (BBCC genomes), and one clone, pOa237, was isolated from Oryza australiensis accession 100882 (EE genome). Southern blot hybridization to different rice genomes showed strong hybridization of all five clones to O. minuta genomic DNA and no cross hybridization to genomic DNA from Oryza sativa (AA genome). The pOm1 and pOmA536 sequences showed cross hybridization only to all of the wild rice species containing the C genome. However, the pOm4, pOmPB10, and pOa237 sequences showed cross hybridization to O. australiensis genomic DNA in addition to showing hybridization to the O. minuta genomic DNA.     

西瓜小叶脉超微结构研究

用透射电子显微技术研究了西瓜叶片小叶脉,结果表明,小叶脉是由大型维管束鞘细胞包围的维管束,维管束呈现大的头部和线形的柄部,柄部是单列细胞的木质部,由维管薄壁细胞和导管分子组成;头部是韧皮部,由维管薄壁细胞、伴胞和筛管分子组成。同一小叶脉内常见有超微结构特征显著不同的两种伴胞：一种伴胞体积小,与维管束鞘细胞接触面较小或不接触,细胞内有大液泡,细胞壁上没有胞间连丝或只有少数不分枝的胞间连丝,这种伴胞为2a型;另一种伴胞体积大,通常位于韧皮部两翼,不含大液泡而含大量小泡,与维管束鞘细胞接触面较大,接触面上有大量具分枝的胞间连丝,分枝部分比未分枝部分直径小,这种伴胞为中间细胞类型。显然,西瓜是小叶脉内兼具两种类型伴胞的植物。     

西瓜小叶脉超微结构研究

用透射电子显微技术研究了西瓜叶片小叶脉,结果表明,小叶脉是由大型维管束鞘细胞包围的维管束,维管束呈现大的头部和线形的柄部,柄部是单列细胞的木质部,由维管薄壁细胞和导管分子组成;头部是韧皮部,由维管薄壁细胞、伴胞和筛管分子组成。同一小叶脉内常见有超微结构特征显著不同的两种伴胞:一种伴胞体积小,与维管束鞘细胞接触面较小或不接触,细胞内有大液泡,细胞壁上没有胞间连丝或只有少数不分枝的胞间连丝,这种伴胞为2a型;另一种伴胞体积大,通常位于韧皮部两翼,不含大液泡而含大量小泡,与维管束鞘细胞接触面较大,接触面上有大量具分枝的胞间连丝,分枝部分比未分枝部分直径小,这种伴胞为中间细胞类型。显然,西瓜是小叶脉内兼具两种类型伴胞的植物。     

Effect of pH on Glutamine Content Derived from Exogenous Glutamate in Astrocytes

Abstract: A shift in pH from 7.4 to 7.8 in the incubation solution caused a 3.4-fold increase in the free glutamine content of mouse cerebral astrocytes that were incubated with glutamate (100 μ M ) and ammonium (100 μ M ). This large and reversible steady-state increase in glutamine content was accompanied by smaller transient increases in the following: (a) net formation of glutamine; (b) clearance of glutamate from the incubation solution; and (c) glutamate content. The content of glutamine was reduced markedly by omission of either glutamate or ammonium from the incubation solution, or by inhibition of glutamine synthetase activity with methionine sulfoximine. The rate at which glutamine was exported from the astrocytes was unaffected by the pH change. The effects of pH on the concentration of free ammonia or on glutamate uptake do not appear to mediate the increase in glutamine content. Uptake of exogenous glutamine was little affected by the pH change. Therefore, possible mediation of the effect by an increase in intracellular pH must be considered. The response to altered pH described here may provide a cellular basis for the increased level of brain glutamine observed in hyperammonemia.     

不同叶位整形模式对白肋烟生长及烟叶多酚物质含量的影响

叶位整形是一项促进烟叶生长和品质提高的栽培管理措施,为明确不同叶位整形模式对白肋烟生长及多酚物质含量的影响,我们在白肋烟主产区—湖北省恩施州研究了不同叶位整形模式下不同生育期白肋烟的叶面积、叶绿素含量(CCI值)、各器官生物量和上下位叶片中多酚物质含量。结果表明:叶位整形显著影响了白肋烟生长和烟叶多酚物质含量,不但增大了不同叶位烟叶的叶面积及CCI值,还协调了各器官生物量、营养物质的合理分配以及不同叶位烟叶中多酚物质的含量;但不同叶位整形模式对白肋烟的生长影响不同,即旺长期整形(WZ)处理对白肋烟整株的促进作用较好,而团棵后期整形(TH)处理仅对上位叶效果较好。本研究采用的叶位整形栽培管理技术在保证白肋烟产量的同时,可在一定程度上促进白肋烟生长及烟叶品质的提高。     

Nitrogen Effects on Leaf Anatomy within the Intercalary Meristems of Tall Fescue Leaf Blades

Longitudinal elongation contributes most to leaf area expansionof grasses and its rate is known to be strongly affected byN. Our objective was to determine the effect of two N regimes(N₀and N+) on the gradient of leaf tissue formation in meristemsof two contrasting tall fescue (Festuca arundinacea Schreb.)genotypes. Proportions of epidermal, mesophyll and vasculartissue as well as intercellular air space were determined throughoutthe base of actively elongating leaves. The area of leaf transversesections nearly doubled between the ligule and the distal endof the growth zone (about 30 mm), and was mainly associatedwith lateral epidermal and mesophyll cell division in the proximal5.0–7.5 mm. Further increase in transverse area was dueto the formation of intercellular airspace and transverse expansionof epidermal cells. Depending on genotype and N treatment themesophyll, epidermis, vascular bundles and air space comprised45–54%, 20–28%, 6–9%, and 17–21%, respectively,of transverse leaf area in the distal part of the growth zone.After a slight increase close to the leaf base, the area ofvascular tissue remained constant throughout the growth zone.The proportion of air space to mesophyll space was higher atN₀than at N+ because mesophyll area was enhanced by N+ to agreater degree than by N₀. In the genotype with slow leaf elongation,the increase in cross-sectional leaf area was due to an increasein both leaf width and leaf thickness. In the genotype whichhad faster leaf elongation and wider leaves, only leaf thicknesswas enhanced by N+. Copyright 2001 Annals of Botany Company Festuca arundinacea(Schreb.), tall fescue, leaf anatomy, growth zone, nitrogen     

低NPK胁迫对橡胶树实生苗新生叶蓬NPK含量的影响

以橡胶树3个品种（GT1、RRIM600、PR107）实生苗为材料,研究正常施肥到低NPK胁迫和恢复正常施肥过程中叶片NPK含量的变化。结果表明：橡胶树实生苗新生叶蓬叶片NPK含量与NPK亏缺与否和胁迫处理的时间密切相关,且胁迫后的缺素状况可通过适时恢复正常施肥得以缓解或改善;叶片N、P、K含量出现降增的时间及幅度有所不同,其中N素的响应较快,P素次之,K素最为缓慢;在低NPK胁迫情况下,N、P、K素间存在不同的互作现象;不同品种叶片养分含量的变化趋势基本一致,但耐受低NPK的胁迫能力及恢复能力有所不同,RRIM600较为敏感,PR107次之,GT1较不敏感。     

The Effect of the Fruit and Exogenous Hormones on Leaf Expansion and Composition in Citrus

Sanz, A., Martinez Cortina, C. and Guardiola, J. L. 1987. Theeffect of the fruit and exogenous hormones on leaf expansionand composition in Citrus.—J. exp. Bot. 38: 2033-2042. The effect of the developing flowers and fruitlets on leaf expansionand composition has been determined in leafy inflorescencesof Citrus sinensis L. Osbeck. During leaf expansion the developingflowers do not compete with the leaves, and their early removaldoes not affect leaf size and composition. Competition for mineralelements is established after flower opening, once leaf expansionis complete. No effect of the fruit on metabolizable carbohydratesin the leaves was found up to day 22 after flower opening. The response to exogenously applied growth regulators suggeststhat the differences in weight and composition between inflorescenceleaves and leaves from vegetative sprouts may be due to hormonally-mediateddifferences in sink strength. Gibberellic acid enhances laminaexpansion and increases the sink strength of the leaves. Kinetinenhances lamina expansion without affecting sink strength. Leafgrowth is directly related to both soluble and wall-bound acidinvertase activities; however, the GA₃ effects on leaf growthand sink strength are unrelated to invertase activity and tothe rate of starch accumulation. Key words: Acid invertase, amylase, carbohydrates, Citrus, leaf growth     

Mode of Attack on Orchardgrass Leaf Blades by Rumen Protozoa

Leaf blade sections of orchardgrass were incubated with rumen fluid and examined by scanning and transmission electron microscopy for the mode of attack on tissues by rumen protozoa. Rumen protozoa resembling Epidinium ecaudatum from caudatum degraded forage tissue in diluted, whole rumen fluid suspensions of microbes containing 1.6 mg of streptomycin per ml, which inhibited bacterial fiber-digesting activity. Cell walls of mesophyll, parenchyma bundle sheath, and epidermis became swollen and frayed to reveal a microfibrillar network and loss of electron density, indicating partial degradation. Then the protozoa ingested whole cells and fragments of cell walls with the aid of their cilia. Plant cells with partially degraded walls as well as chloroplasts without walls were present within the protozoa. These entodiniomorphs digested orchardgrass leaves by partially degrading the plant cell walls apparently by extracellular enzymes and then ingestion of the plant cells and cell wall fragments.     

Leaf surface fungi of Oryza sativa Linn

An investigation into the fungal population of phyllosphere and phylloplane regions of green and newly detached yellow leaves ofOryza sativa was undertaken. The dominant fungal species in the phyllosphere-regions of green and yellow leaves mostly differed. The following trend was exhibited in the appearance of the dominant species in the phyllosphere at different stages of plant growth. No dominant form was isolated from phyiloplane region of green leaves.Phoma sp. was continuously isolated as dominant from the phylloplane of yellow leaves.A number of species, though present abundantly on the phyllosphere regions of green and yellow leaves, were not obtained from their respective phylloplane regions.     

玉米叶片原形成层细胞衰退过程的超微结构研究

Cell degeneration often occurred in Zea mays L. leaf procambium in various stages of development and could be classified either in the form of autolysis or condensation. In the autolytic degeneration the cells underwent a series of events from the appearance of prominant autophagie activity in the early stages, accompanied by a decrease of ribosomes and electron density of cytoplasm to the final stages of autolysis resulting in disorganization and disappearnce of all protoplasmic components, of which the nuclei and plasmalemma were the last to disappear. In the condensed type the initiation of cell degeneration was accompanied by an increase in the cytoplasmic density. As cell degeneration progressed, the protoplasmic components appeared to disintegrate and disappear in an orderly fashion i.e. dictyosomes and ER disorganized first, followed by plastids, nuclei and some mitochondria. The plasmalemma, ribosomes and mitochondria were still recognizable as the cell being crashed by the surrounding cells during the final stages of degeneration.     

中国稻属植物叶片亚显微结构比较研究

用扫描电镜对原产中国的3种野生稻和2个栽培稻品种的叶片表面亚显微结构,尤其是气孔列数、气孔频度、气孔器乳突、大瘤状乳突、小栓细胞乳突等进行比较研究。结果显示,气孔频度的变化趋势是沿着疣粒野生稻-药用野生稻-栽培稻IR36-簿通野生稻-栽培稻珍汕97逐渐增大,其变化幅度在635-1737个／mm^2之间;气孔器乳突除疣粒野生稻为6个外,其余通常为4个;疣粒野生稻既无大瘤状乳突亦无木栓细胞乳突．药用野生稻无木栓细胞乳突。这些性状不仅具什种的特异性,而且与亲缘关系远近有关,可以作为稻属分类的依据。     

Histochemical Localization of Phenolic Deposits in Leaf Blades of Eragrostis racemosa

The distribution of phenolic deposits in the leaves of Eragrostisracemosa from different habitats was investigated during cultivationunder uniform environmental conditions. The plants retainedtheir leaf phenolic distribution pattern over a period of 8months. Plants from dry habitats had phenolic inclusions inboth epidermal layers, whereas phenolic deposits were absentor only occurred in the abaxial epidermal layers of plants occupyingmoist habitats. Eragrostis racemosa, narrow-heart love grass, Poaceae, phenolic deposits, epidermis, histochemistry, anatomy     

The Role of Meristematic Activities in the Formation of Leaf Blades

Arabidopsis thaliana (L.) Heynh. Leaf primordia also have their own meristematic regions and meristematic activity is maintained in part of the leaf blade, in some case, even after maturation. Transgenic plants have been generated that have proved to be useful tools in the analysis of the behavior of meristematic regions in leaf blades of A. thaliana. This review, based on our present understanding of molecular mechanisms for the maintenance and development of shoot apical meristems in A. thaliana, summarizes the variations in patterns and functions of meristematic regions in leaf blades focusing, in particular, on the case of indeterminate leaves. Received 5 April 2000/ Accepted in revised form 12 April 2000     

Salt‐Treated Roots of Oryza australiensis Seedlings are Enriched with Proteins Involved in Energetics and Transport

Salinity is a major constraint on rice productivity worldwide. However, mechanisms of salt tolerance in wild rice relatives are unknown. Root microsomal proteins are extracted from two Oryza australiensis accessions contrasting in salt tolerance. Whole roots of 2‐week‐old seedlings are treated with 80 mM NaCl for 30 days to induce salt stress. Proteins are quantified by tandem mass tags (TMT) and triple‐stage Mass Spectrometry. More than 200 differentially expressed proteins between the salt‐treated and control samples in the two accessions (p‐value <0.05) are found. Gene Ontology (GO) analysis shows that proteins categorized as “metabolic process,” “transport,” and “transmembrane transporter” are highly responsive to salt treatment. In particular, mitochondrial ATPases and SNARE proteins are more abundant in roots of the salt‐tolerant accession and responded strongly when roots are exposed to salinity. mRNA quantification validated the elevated protein abundances of a monosaccharide transporter and an antiporter observed in the salt‐tolerant genotype. The importance of the upregulated monosaccharide transporter and a VAMP‐like protein by measuring salinity responses of two yeast knockout mutants for genes homologous to those encoding these proteins in rice are confirmed. Potential new mechanisms of salt tolerance in rice, with implications for breeding of elite cultivars are also discussed.