干旱对东北春玉米生长发育和产量的影响

选取玉米品种丹玉39为供试材料,利用大型农田水分控制试验场,采用大田池栽方式,在玉米三叶-拔节期、拔节-吐丝期、吐丝-乳熟期分别开展中度干旱胁迫及复水控制对比试验,分析3个关键生育时期干旱胁迫对春玉米生长发育和产量的影响.结果表明：与水分适宜对照（CK）相比,三叶-拔节期遭受干旱胁迫后,全生育期推迟13 d,至拔节普遍期,株高偏低29.8%,叶面积偏小41.2%,复水后,株高和产量得到较大程度恢复,果穗性状和最终产量差异不大;拔节-吐丝期遭受干旱胁迫后,全生育期缩短7 d,至吐丝普遍期,株高偏低18.6%,叶面积偏小14.1%,果穗长、穗粒数、果穗干质量、穗粒质量分别下降6.9%、19.1%、28.1%和29.4%,空秆率增加13.3%;吐丝-乳熟期遭受干旱胁迫后,全生育期缩短15 d,生长至乳熟普遍期,株高偏低2.3%,叶面积偏小37.3%,果穗长、穗粒数、果穗干质量、穗粒质量分别下降9.2%、24.1%、30.8%和27.9%,空秆率增加24.5%.拔节-吐丝期、吐丝-乳熟期干旱胁迫处理并复水后,玉米株高恢复不明显,产量降幅显著.     

干旱胁迫对玉米叶片光合特性和穗发育特征的影响

玉米是需水量较大的粮食作物之一,拔节至开花的穗期是其一生中的需水临界期,研究玉米穗期对干旱胁迫的响应机制对提高玉米干旱适应性具有重要意义。以筛选后的干旱敏感自交系PH6WC(6WC)和抗旱自交系郑58(Z58)为试验材料,采用测坑控水试验,于穗期设置3个水分处理(正常灌水CK、轻度干旱LD、中度干旱MD),研究了穗期不同水分处理对雌雄穗发育特性、开花吐丝间隔以及穗位叶光合特性的影响。结果表明:LD对Z58的株高、雄穗生长特性、叶绿素相对含量和光系统II最大光化学效率没有显著影响,但雌穗长显著降低;MD显著降低了Z58的穗位叶光合特性、雌雄穗的穗长和干物质积累。对于6WC,LD抑制了其植株生长和穗的发育,使雌穗长、雌穗直径、雄穗长、干物质向穗的分配比率、穗位叶的叶绿素a、叶绿素b和光合性能综合指数(PIABS)分别降低了35.3%、11.8%、20.6%、25%、21.1%、20%、23.8%;干旱胁迫程度越重对6WC雌雄穗的发育影响越大。此外,LD与MD分别延长6WC的开花吐丝间隔期(ASI)至5天、9天,LD和MD分别延长Z58的ASI 0、3天。综上所述:穗期的干旱胁迫在不同程度上影响了6WC和Z58穗位叶的光合特性,但是对干旱敏感自交系6WC雌雄穗的生长发育的抑制显著高于Z58,以至于降低了干物质向穗部的积累与分配。     

Impact of brown stink bug (Heteroptera: Pentatomidae) feeding on corn grain yield components and quality

Brown stink bug, Euschistus servus (Say) (Heteroptera: Pentatomidae), damage on developing corn, Zea mays L., ears was examined in 2005 and 2006 by using eight parameters related to its yield and kernel quality. Stink bug infestations were initiated when the corn plants were at tasseling (VT), mid-silking (R1), and blister (R2) stages by using zero, three, and six in 2005 or zero, one, two, and four bugs per ear in 2006, and maintained for 9 d. The percentage of discolored kernels was affected by stink bug number in both years, but not always affected by plant growth stage. The growth stage effect on the percentage of discolored kernels was significant in 2006, but not in 2005. The percentage of aborted kernels was affected by both stink bug number and plant growth stage in 2005 but not in 2006. Kernel weight was significantly reduced when three E. sercus adults were confined on a corn ear at stage VT or R1 for 9 d in 2005, whereas one or two adults per ear resulted in no kernel weight loss, but four E. servus adults did cause significant kernel weight loss at stage VT in 2006. Stink bug feeding injury at stage R2 did not affect kernel damage, ear weight or grain weight in either year. The infestation duration (9 or 18 d) was positively correlated to the percentage of discolored kernels but did not affect kernel or ear weight. Based on the regression equations between the kernel weight and stink bug number, the gain threshold or economic injury level should be 0.5 bugs per ear for 9 d at stage VT and less for stage R1. This information will be useful in developing management guidelines for stink bugs in field corn during ear formation and early grain filling stages.     

氮高效玉米主要性状的遗传分析

采用两个氮高效玉米杂交组合的P1、P2、F1、F2、B1、B2世代,随机区组试验设计,对氮高效玉米主要性状的遗传力进行了研究。研究结果表明,不同氮水平下氮高效玉米各性状的遗传力是不同的。低氮处理中,广义遗传力介于0.78～0.46之间,狭义遗传力介于0.68～0.23之间;高氮处理中,广义遗传力介于0.76～0.49之间,狭义遗传力介于0.67～0.25之间。低氮条件下,氮高效玉米主要性状中抽丝期穗位叶叶绿素含量、氮效率、穗重和穗位叶叶面积,高氮条件下,抽丝期生物量、穗重、抽丝期穗位叶叶绿素含量和成熟期生物量等性状的遗传力较高,可分别在低氮、高氮条件下,对其进行早代选择。     

Effect of Temperature on Ear Abnormalities in Uniculm Barley

Field experiments with a uniculm mutant of Proctor spring barleyshowed that abnormal ear development often resulted from latesowing. The ear abnormalities were twin floret, supernumeraryparts, abnormal rachilla, opposite spikelets, one-ranked spikelets,branched rachis, collar -like and bare nodes, aborted apex,and tubular leaf. The degree of abnormality was unaffected byphotoperiod. In both uniculm Proctor and uniculm Kindred, nodenumber relative to normal genotype was decreased by high-temperaturetreatment and the proportion of abnormal rachis nodes and theseverity of the abnormality were increased. The transfer ofplants from high to low temperature and vice versa at differentstages of development showed that high temperature had an almostimmediate effect, inducing abnormal development, but that transferto low temperatures allowed the resumption of more normal development. The abnormalities closely resemble those induced by 2, 4.D andit may be that the effect of the mutant gene is in some wayto change the metabolism of auxin.     

Development of the Vascular System in the Ear of Barley

In the mature rachis internodes of a two-row barley ear therewere two large lateral vascular bundles and a number of smallermedian and outer lateral vascular bundles. These bundles rannearly the full length of the rachis with no cross connectionsbetween them. The lateral and the outer lateral bundles branchedat every node while the median bundles branched at every othernode. The vascular bundles to each spikelet passed through acomplex region in which transfer cells occurred. Development of the vascular system of the young main shoot earstarted at the triple mound stage when the procambium of lateralbundles was initiated. Initiation of the median bundles andthe outer lateral bundles followed in sequence with some differentiationof protophloem and protoxylem. At awn initial stage of the earthe vascular connections to the spikelets were established withdifferentiation of the almost complete procambium proceedingthroughout the ear elongation phase. The progress of vascularisation in the young ear is discussedwith reference to spikelet initiation, ear relative growth rateand death of terminal spikelets. It is proposed that the changesin the relative growth rate of the ear and death of the terminalspikelets may be related to vascular differentiation     

Cell proliferation during the early compartmentalization of the Xenopus laevis inner ear

The auditory and vestibular endorgans of the inner ear which are essential for the senses of hearing and balance form early during development when the otocyst undergoes a period of rapid growth and compartmentalization. Here we show the spatial and temporal patterns of proliferating cells in the Xenopus laevis inner ear as this organ develops from an otic vesicle at stage 31 until stage 47, an age at which compartmentalization and the initial appearance of sensory structures are evident. Sites of new cell production were identified in specimens at stages 31, 37, 42, 45 and 47 using immunohistochemical methods to detect bromodeoxyuridine (BrdU) incorporation three hours after exposure to this thymidine analogue. Cells undergoing terminal mitosis at stages 37, 42 and 45 were detected by exposing specimens at these stages to BrdU and permitting development to proceed until stage 47. Our results show that while newly replicating cells are uniformly distributed throughout the stage 31 otic vesicle, they are spatially restricted in stages 37 through 45, with few dividing cells visible in the central patches of the emerging sensory epithelia. In contrast, no clear proliferative pattern was discerned at stage 47. BrdU-positive cells that had undergone terminal mitosis at stage 37, 42 and 45 were detected in the central regions of nascent sensory epithelia at stage 47. These findings are consistent with a developmental mechanism in which cells undergoing terminal mitosis during early X. laevis stages contribute to sensory epithelia and in which cell mixing and migration are features of inner ear compartmentalization.     

In vitro development of the embryonic mouse inner ear following exposure to trypsin

Trypsin has been shown to disrupt normal in vitro morphogenesis of embryonic organ rudiments. Otic tissues derived from 11-, 12-, and 13-day-old mouse embryos were exposed to either Ca++- and Mg++-free PBS or 0.25% trypsin dissolved in Ca++- and Mg++-free PBS prior to explanation into organ culture. Trypsin treatment of otic explants disrupted the expression of the normal pattern of inner-ear development in vitro. There was a direct correlation between the embryonic age at time of exposure to trypsin and the severity of dysmorphogenesis of the inner ear. The younger explants showed abnormalities of both vestibular and auditory structures, whereas with increasing embryonic age, abnormalities were confined more to the auditory portion of the inner ear. The results suggest that integrity of the otocyst basal lamina and epitheliomesenchymal tissue interactions are important factors in early otic development. It is postulated that the major effect of trypsin on inner-ear morphogenesis is through disruption of these factors, which may act to regulate the progressive expression of early otic development.     

MRI Findings of Otic and Sinus Barotrauma in Patients with Carbon Monoxide Poisoning during Hyperbaric Oxygen Therapy

Background and Purpose

To study the MRI findings of otic and sinus barotrauma in patients with carbon monoxide(CO) poisoning during hyperbaric oxygen (HBO) therapy and examine the discrepancies of otic and sinus abnormalities on MRI between barotrauma and acute otitis media with effusion.

Materials and Methods

Eighty patients with CO-poisoning diagnosed with otic and sinus barotrauma after HBO therapy were recruited. Brain MRI was performed to predict delayed encephalopathy. Over the same period, 88 patients with acute otitis media with effusion on MRI served as control. The abnormalities of the middle ear and paranasal sinuses on MRI were noted and were compared between groups. Nine patients with barotrauma were followed up by MRI.

Results

In the barotrauma group, 92.5% of patients had bilateral middle ear abnormalities on MRI, and 60% of patients had both middle ear cavity and mastoid cavity abnormalities on MRI in both ears. Both rates were higher than those in the control group (p = 0.000). In the two groups, most abnormalities on MRI were observed in the mastoid cavity. The rate of sinus abnormalities of barotrauma was 66.3%, which was higher than the 50% in the control group (p = 0.033). In the nine patients with barotrauma followed up by MRI, the otic barotrauma and sinus abnormalities had worsened in 2 patients and 5 patients, respectively.

Conclusion

MRI is able to depict the abnormalities of otic and sinus barotrauma in patients with CO-poisoning during HBO therapy and to differentiate these from acute otitis media with effusion.     

The Control of Leaf and Ear Size in Barley

The relative growth rates, growth rates, and final size of tillersand main-shoot leaves, internodes, and ear of a freely tilleringspring barley genotype were measured and compared with thoseof a non-tillering single-gene mutant. Leaf and internode growthand final size were greater in the non-tillering mutant. Thedifferences, it is proposed, arise because of changes in internalcompetition for assimilates brought about by the absence oftillers. There was little difference in ear growth or size,possibly because of abnormalities of ear development, whichresulted in fewer spikelets in the non-tillering genotype.     

Developmental expression of otoconin-22 in the bullfrog endolymphatic sac and inner ear.

In amphibians, calcium carbonate crystals are present in the endolymphatic sac and the inner ear. The formation of these crystals is considered to be facilitated by a protein called otoconin-22. We examined the spatial and temporal expression of otoconin-22 during the development of the bullfrog (Rana catesbeiana) using RT-PCR, in situ hybridization (ISH), and immunofluorescence techniques. By RT-PCR, otoconin-22 mRNA was first detected in embryos at Shumway stage 20, and this expression pattern continues in late stages. The first otoconin-22 mRNA-positive reaction was detected in stage 22 embryos in the placode of the endolymphatic sac. Otoconin-22 protein was observed in the epithelial cells of the endolymphatic sac at stage 24. On the other hand, a whole-mount ISH technique showed the first expression of otoconin-22 mRNA in the inner ear, in addition to the endolymphatic sac, at the mid-phase of Shumway stage 25. We discuss the role of otoconin-22 in the formation of calcium carbonate crystals in the endolymphatic sac and inner ear.     

Proteome analysis of rice uppermost internodes at the milky stage

Uppermost internodes, which connect the part between the ear and lower stem, form an important pathway transporting mineral nutrition from roots and photosynthates from leaves (especially the flag leaf) to the ear. The milky stage is the first stage of seed ripening. The uppermost internodes of rice at the milky stage are critical for seed quality and yield. Total soluble proteins of the uppermost internodes of rice (Oryza sativa L. ssp. indica) at the milky stage were analyzed using proteomic methods. Using 2-DE, 762 reproducible protein spots were detected. Among them, 132 abundant proteins were analyzed using MALDI-TOF-MS. Searching in the National Center for Biotechnology Information database, we could identify 98 proteins, which represent 80 gene products. These proteins belong to 11 functional groups with energy production-associated proteins in the first place. The large accumulation of proteins involved in metabolism, signaling, and stress resistance indicated that the uppermost internodes of rice have a high physiological and stress-resistant activity. In addition, our results will also enrich the database of the rice proteome.     

Organogenesis of Fascicled ear mutant inflorescences in maize (Poaceae)

The ontogeny of staminate tassels and pistillate ears in the maize mutant Fascicled ear was examined using scanning electron microscopy. The normal pattern of inflorescence development is perturbed by the Fascicled ear mutation at the transition stage. The Fascicled ear mutation promotes the development of an abnormal transition stage axis that is both shorter and broader than the wild type. The inflorescence apical meristem then undergoes a bifurcation, and two inflorescence axes arise in place of a single axis. Each derived inflorescence apical meristem may undergo a similar perturbation sequence. This expression of the Fascicled ear mutation may be repeated one to several times, which leads to the development of a fascicled pistillate inflorescence and a fascicled central spike in the staminate inflorescence. The apical meristems of some tassel branches are also bifurcated. Subsequent organogenesis during paired-spikelet and floral development in Fascicled ear plants follows the pattern of normal maize. However, triplet spikelets are occasionally observed. The organogenic disruption by the Fascicled ear mutation that we describe will aid genetic and molecular analysis on the regulation of inflorescence development in maize and other members of the genus Zea.     

Clinical imaging findings in a girl with Hutchinson-Gilford progeria syndrome

We report an 82-year-old girl with premature aging, a karyotype of 46,XX and a de novo c.1824C>T mutation encoding p.G608G in the lamin A gene. The clinical features of accelerated aging and the molecular finding were consistent with the diagnosis of Hutchinson-Gilford progeria syndrome (HGPS). In this presentation, we demonstrate the radiological imaging findings of skeletal, oral and craniofacial phenotypes of abnormalities associated with HGPS. The oral and craniofacial abnormalities caused dental caries, severe malocclusion, and swallowing, feeding and speech problems. Dural calcification, and granulation in the ear drum and external ear canal were additionally observed.     

Glycolipid and phospholipid composition of wheat and barley chloroplasts

Composition of complex lipid of chloroplasts of two cultivars of wheat and barley was determined at tillering, ear emergence and grain filling stages. The chloroplast lipids, MGDG, DGDG and PG were maximum at grain filling stage in both wheat and barley. PC content showed variations at different stages in both the crops while no significant changes were observed in PI concentrations at grain filling stage.     

Seasonal changes in canopy photosynthesis and respiration, and partitioning of photosynthate, in rice (Oryza sativa L.) grown under free-air CO2 enrichment

An increase in atmospheric CO(2) concentration ( [CO(2)]) is generally expected to enhance photosynthesis and biomass. Rice plants (Oryza sativa L.) were grown in ambient CO(2) (AMB) or free-air CO(2)-enrichment (FACE), in which the target [CO(2)] was 200 micromol mol(-1) above AMB. (13)CO(2) was fed to the plants at different stages so we could examine the partitioning of photosynthates. Furthermore, canopy photosynthesis and respiration were measured at those stages. The ratio of (13)C content in the whole plant to the amount of fixed (13)C under FACE was similar to that under AMB at the vegetative stage. However, the ratio under FACE was greater than the ratio under AMB at the grain-filling stage. At the vegetative stage, plants grown under FACE had a larger biomass than those grown under AMB owing to enhancement of canopy photosynthesis by the increased [CO(2)]. On the other hand, at the grain-filling stage, CO(2) enrichment promoted the partitioning of photosynthate to ears, and plants grown under FACE had a greater weight of ears. However, enhancement of ear weight by CO(2) enrichment was not as great as that of biomass at the vegetative stage. Plants grown under FACE did not necessarily show higher canopy photosynthetic rates at the grain-filling stage. Therefore, we concluded that the ear weight did not increase as much as biomass at the vegetative stage owing to a loss of the advantage in CO(2) gain during the grain-filling period.     

Dysmorphogenesis of the inner ear: disruption of extracellular matrix (ECM) formation by an L-proline analog in otic explants

L-azetidine-2-carboxylic acid (LACA), a l-proline analog, disrupts collagen secretion by cells and prevents normal morphogenesis of in vitro developing organ rudiments. Otic explants derived from 10.5-through 14-day-old mouse embryos were continuously exposed to LACA in the nutrient medium at concentrations of 75, 150, and 300 micrograms/ml. LACA disrupted normal in vitro otic morphogenesis in inner ears explanted from embryos of 10.5 through 13 days' gestation. Development of 14-day-old otic explants were not affected by LACA at the concentrations tested. There was a direct correlation between the embryonic age of the explant when exposed to LACA, and the severity of otic dysmorphogenesis. The younger explants (10.5-to 12-day-old) developed abnormalities of both vestibular and auditory structures, but with increasing embryonic age of the explants (12-to 13.5-day-old) abnormalities were confined more to the auditory portion of the inner ear. Disruption of collagen secretion of connective tissue cells of the otic explants are a major teratogenic action of LACA on inner ear development. Disrupted collagen secretion alters otic extracellular matrix production, which in turn affects the tissue interactions that regulate the progressive expression of otic morphogenesis and differentiation.