昼夜温差对番茄生长发育、产量及果实品质的影响

在3间人工气候室精密受控环境中,保持日平均温度为22 ℃,设置昼夜温差分别为6 ℃(25 ℃/19 ℃)、8 ℃(26 ℃/18 ℃)、10 ℃(27 ℃/17 ℃),研究昼夜温差对番茄生长的影响.结果表明: 番茄不同品种、不同生长时期适宜的昼夜温差条件不同.番茄开花前,与6 ℃温差相比,8 ℃温差可显著加快野生种醋栗番茄LA1781生长发育,使幼苗株高增加23.1%,出叶加快1～2片,开花提前7 d;10 ℃温差对LA1781苗期的促进作用与8 ℃温差相似.对栽培种普通番茄LA2397和LA0490来说,6 ℃温差使幼苗生长良好,8 ℃温差对幼苗无显著促进作用;与6 ℃温差相比,10 ℃温差对苗期生长及开花有抑制作用,使株高降低12.0%～18.3%,出叶慢2～3片,开花推迟2～4 d.10 ℃温差使3个品种番茄地上部分干质量增加25.2%～44.2%.番茄开花后,与6 ℃温差相比,10 ℃温差可显著提高LA1781的产量和果实品质,使果实数增加34.7%,单株产量增加92.1%,平均单果质量增加40.0%,果实可溶性糖含量增加16.3%,番茄红素含量增加95.6%.与6 ℃温差相比,LA2397和LA0490在8 ℃温差下产量和果实品质提高,番茄红素含量增加超过2倍;在10 ℃温差下产量略有降低(5.0%),果实含糖量降低,但果实尺寸和番茄红素含量增加.表明番茄苗期生长温差不宜过大,花果期适当增大昼夜温差可提高产量和果实品质,但温差过大易造成生长不良和减产.     

Factors controlling in vitro hatching of Vairimorpha plodiae (Microspora) spores and their infectivity to Plodia interpunctella,Heliothis virescens, and Pieris brassicae

Factors which influence the hatching of spores and proliferation of stages of the microsporidium Vairimorpha plodiae in two susceptible insects, Plodia interpunctella and Heliothis virescens, and one nonsusceptible insect, Pieris brassicae, were investigated. Spores hatched in 0.1 and 1 m KCl solutions when subjected to a change in pH, from pH 11 to pH 8. K⁺ was essential for hatching; NaCl solutions were not effective. Ca²⁺ and Mg²⁺ inhibited hatching, and calcium and magnesium chelating agents enhanced it. All three insect species had alkaline midgut contents and smooth, fragile peritrophic membranes. Spores hatched inside the midguts of all three insect species (P. interpunctella: maximum rate, 92.5%; H. virescens, 91.5%; P. brassicae, 82%). Sporoplasms were observed in the midgut epithelial and associated tracheole cells of P. brassicae. Both H. virescens and P. brassicae became infected when injected intrahemocoelically with spores.     

Developmental and hormonal regulation of midgut remodeling in a lepidopteran insect, Heliothis virescens

Midgut tissue undergoes remodeling during metamorphosis in insects belonging to orders Lepidoptera and Diptera. We investigated the developmental and hormonal regulation of these remodeling events in lepidopteran insect, Heliothis virescens. In H. virescens, programmed cell death (PCD) of larval midgut cells as well as proliferation and differentiation of imaginal cells began at 108 h after ecdysis to the final larval instar (AEFL) and proceeded through the pupal stages. Expression patterns of pro- cell death factors (caspase-1 and ICE) and anti-cell death factor, Inhibitor of Apoptosis (IAP) were studied in midguts during last larval and pupal stages. IAP, Caspase-1 and ICE mRNAs showed peaks at 48 h AEFL, 96 h AEFL and in newly formed pupae, respectively. Immunohistochemical analysis substantiated high caspase-3 activity in midgut at 108 h AEFL. Application of methoprene, a juvenile hormone analog (JHA) blocked PCD by maintaining high levels of IAP, downregulating the expression of caspase-1, ICE and inhibiting an increase in caspase-3 protein levels in midgut tissue. Also, the differentiation of imaginal cells was impaired by methoprene treatment. These studies demonstrate that presence of JHA during final instar larvae affects both midgut remodeling and larval-pupal metamorphosis leading to larval/pupal deformities in lepidopteran insects, a mechanism that is different from that in mosquito, Ae. aegypti where JHA uncouples midgut remodeling from metamorphosis.     

Effects of temperature on calcium deposition in the hard-shell clam, Mercenaria mercenaria

A radiographic technique was developed and employed to determine the effects of temperature variation on the rate and distributive pattern of calcium deposition in the shell of the marine clam Mercenaria mercenaria (Linne). Both the rate and pattern of calcification were found to be significantly affected by temperature variation. Two optimal temperatures for maximum overall shell growth were found at approx. 12.8–15.6 and 23.9°C. At all temperatures but the lowest one tested (4.4°C), a higher rate of calcification was found peripherally than centrally in the shell. The pattern of calcium incorporation in the central portions of the shell was irregular and often discontinuous.     

昼间亚高温对日光温室番茄生长发育、产量及品质的影响

针对日光温室番茄生产中常出现的昼间温度偏高而带来的危害,以昼间适宜温度25℃为对照,在番茄第1花序开花后对其进行昼间30和35℃的温度处理,研究昼间亚高温对番茄生长发育、产量及品质的影响.结果表明,与25℃适宜昼温相比,在3d短期35℃昼间亚高温处理下,番茄植株相对生长速率极显著提高,但在7d以上长期35℃昼间亚高温处理下,番茄植株徒长,叶片变薄,并出现早衰现象;同时经35℃亚高温处理,番茄果实前期发育加快,成熟期提前,但果实空洞现象增加,糖酸比下降,平均单果重下降,总产量显著降低,第3花序各处理间差异最明显,第2花序次之.昼间30℃温度处理的结果介于昼间25和35℃处理之间,说明番茄植株长期生长在被认为是其生长发育适宜温度上限的35℃条件下,也会严重影响其正常生长发育,而且从花芽分化到果实成熟亚高温持续时间越长,番茄果实产量越低,品质越差.     

Purification, characterization, and substrate specificity of two 2,3-dihydroxybiphenyl 1,2-dioxygenase from Rhodococcus sp. R04, showing their distinct stability at various temperature

The genes of two 2,3-dihydroxybiphenyl 1,2-dioxygenases (BphC1 and BphC2) were obtained from the gene library of Rhodococcus sp. R04. The enzymes have been purified to apparent electrophoretic homogeneity from the cell extracts of the recombinant harboring bphC1 and bphC2. Both BphC1 and BphC2 were hexamers, consisting of six subunits of 35 and 33kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, respectively. The enzymes had similar optimal pH (pH 9.0), but different temperatures for their maximum activity (30 degrees C for BphC1, 80 degrees C for BphC2). In addition, they exhibited distinct stability at various temperatures. The enzymes could cleave a wide range of catechols, with 2,3-dihydroxybiphenyl being the optimum substrate for BphC1 and BphC2. BphC1 was inhibited by 2,3-dihydroxybiphenyl, catechol and 3-chlorocatechol, whereas BphC2 showed strong substrate inhibition for all the given substrates. BphC2 exhibited a half-life of 15min at 80 degrees C and 50min at 70 degrees C, making it the most thermostable extradiol dioxygenase studied in mesophilic bacteria. After disruption of bphC1 and bphC2 genes, R04DeltaC1 (bphC1 mutant) delayed the time of their completely eliminating biphenyl another 15h compared with its parent strain R04, but R04DeltaC2 (bphC2 mutant) lost the ability to grow on biphenyl, suggesting that BphC1 plays an assistant role in the degrading of biphenyl by strain R04, while BphC2 is essential for the growth of strain R04 on biphenyl.     

The combined effects of temperature and salinity on hatching success and the survival,growth, and development of the larval stages of Metapenaeus bennettae (Racek & Dall)

During the spawning season of the estuarine prawn Metapenaeus bennettae (Racek & Dall), laboratory and field experiments were conducted to examine the combined effects of temperature and salinity on hatching success of eggs and the survival, growth and development of larvae. Response surface analysis showed that optimal levels of temperature and salinity for maximum hatching success varied depending on conditions during spawning. Similarly, temperature and salinity conditions that produced maximum survival and growth of larvae depended on conditions during rearing prior to experimental temperature/salinity treatments. At the onset of feeding, larvae showed the lowest tolerance to changes in temperature and salinity. Supplementary feeding experiments in the laboratory, and survival rates in field experiments indicated that starvation was a more potent factor than the effects of temperature and salinity in determining survival through the protozoeal larval stages. Late larval stages were relatively indifferent to the effects of temperature and salinity. It is suggested that, during early development, adaptive response to the prevailing physical conditions enhances survival in an estuarine environment.     

大田增温对夏玉米产量和品质的影响

研究了大田条件下增温（3 ℃）对夏玉米产量和品质的影响. 结果表明：增温条件下玉米的籽粒产量显著降低,农大108（ND108）和掖单13号（YD13）分别减产46.6%和45.1%.增温也显著影响了玉米的籽粒品质,与对照相比,ND108和YD13的粗蛋白含量分别提高了11.6%和2.02%;粗脂肪含量分别降低了38.9%和9.6%;淀粉含量分别降低了7.0%和8.4%,且主要降低了支链淀粉的含量;赖氨酸含量则分别降低了58.9%和51.2%.     

温度对水螅种群增长和个体大小的影响

应用群体累积培养法,以枝角类为食物,在10℃、20℃和30℃三种温度下,研究了温度对水螅(Hydra sp．)种群密度、种群增长率和个体大小的影响。结果表明温度对水螅种群密度和个体体积由极显著影响。在培养初期,30℃下的水螅种群密度最大;而在培养后期,20℃下的水螅种群密度则显著大于30℃下的值;10℃下的值则始终最小。在同一温度下,种群增长率均与时间呈曲线相关,10℃、20℃、30℃的回归方程分别为：Y=0．000433X^2-0．00262X 0．00332、Y=-0．003367X^2 0．068335X-0．066489、Y=-0．018469X^2 0．188952X-0．030933。在研究范围内,30℃的水螅个体最小。     

Effects of host stages and temperature on population parameters of Oomyzus sokolowskii, a larval-pupal parasitoid of Plutella xylostella

Oomyzus sokolowskii is alarval-pupal parasitoid of diamondback moth, Plutella xylostella. In a host stage preference test, the parasitoid parasitised all larval and pupal stages, but exhibited a strong preference for larvaeover prepupae or pupae, and did not show a preference among the larval instars. At 25°C, the developmental time, number and sex ratio of offspring per host pupa, and successful parasitism did not differ significantly among parasitoids reared from host larvae of different instars, indicating similar host suitability between larvae of different instars. Mean developmental times from egg to adult at 20, 22.5, 25, 30, 32.5, and 35°C were 26.5,21.0, 16.0, 12.7, 11.9 and 13.4 days, respectively. The favourable temperature range for development, survival, and reproduction of the parasitoid was 20--30°C. However, wasps that developed and emerged at a favourable temperature could parasitise effectively at 32--35°C for 24 hours. Life-fertility table studies at 20, 25, and 30°C showed that each female wasp on average parasitised 3.1, 13.2, 6.8 larvae of diamondback moth and produced 20.5, 92.1, 50.4 offspring, respectively, during her lifetime. The highest intrinsic rate of natural increase (r _m) of 0.263 female/day was reached at 30°C as a result of the short mean generation time at this temperature compared to that at 20 and 25°C, suggesting that the parasitoid had the highest potential for population growth at relatively high temperatures. This revised version was published online in July 2006 with corrections to the Cover Date.     

Some effects of time,temperature and feeding on infection rates with Babesia bovis and Babesia bigemina in Boophilus microplus larvae

Dalgliesh R. J. and Stewart N. P. 1982. Some effects of time, temperature and feeding on infection rates with Babesia bovis and Babesia bigemina in Boophilus microplus larvae. International Journal for Parasitology12: 323–326. Percentages of larval ticks in which Babesia bovis and B. bigemina parasites could be detected (infection rates) were determined after the larvae had been exposed to temperatures between 9°C and 27°C for periods of 1–35 days and then either fed on calves or heated at 37°C to stimulate babesial development. Infection rates with both species increased during 2–4 weeks after the larvae hatched, regardless of the temperature of exposure. Infection rates with B. bovis were higher after exposure of larvae to 14°C than to 27°C. This effect was less pronounced with B. bigemina. Infection rates were higher in fed larvae than in unfed, ‘heat stimulated’ larvae. The findings indicate that infected larval ticks become more efficient vectors of Babesia during the first 2–4 weeks after hatching and that repeated sampling of a tick population is necessary to determine valid infection rates.     

Effect of high air and soil temperature on dry matter production,pod yield and yield components of groundnut

Groundnuts (Arachis hypogaea L.) grown in the semi-arid tropics are commonly exposed to air and soil temperatures above 35 °C during the reproductive period causing significant yield losses. The objectives of this study were to determine: (i) whether effects of high air and/or high soil temperature in two contrasting cultivars were similar; (ii) the effects of the timing of imposition of high air and soil temperature; (iii) the effects of high air, high soil and both stresses combined on yield and yield components; and (iv) whether the effects of high air and high soil temperature were additive or multiplicative. Plants were grown at optimum and ambient soil temperature from planting until start of podding at 45 d after planting (DAP) in Experiment 1, and until start of flowering at 28 DAP in Experiment 2. Thereafter, plants of each cultivar were exposed to a factorial combination of two air temperatures (optimum: 28°/22 °C and high: 38°/22 °C) and two soil temperatures (ambient: 26°/24 °C and high: 38°/30 °C) until final harvest at 90 DAP. The effects of high air and high soil temperatures imposed from start of flowering or podding were similar. Exposure to high air and/or high soil temperature significantly reduced total dry matter production, partitioning of dry matter to pods, and pod yields in both the cultivars. High air temperature had no significant effect on total flower production but significantly reduced the proportion of flowers setting pegs (fruit-set) and hence fruit numbers. In contrast, high soil temperature significantly reduced flower production, the proportion of pegs forming pods and 100 seed weight. The effects of high air and soil temperature were mostly additive and without interaction. This revised version was published online in June 2006 with corrections to the Cover Date.     

Influence of root-zone temperature on growth,development and yield of cucumber plants cv. Toska

Summary In a first experiment, cucumber transplants (cucumis sativa L. cv. Toska) were grwon at five root-zone temperatures (RZT) ranging from 12° to 36°C. Maximum shoot growth and total leaf area were obtained at 24° and 30°C (RZT). In a second experiment, cucumber transplants were submitted to five RZT (12, 18, 24, 30 and 36°C) and five night air temperatures (NAT) that were maintained either constant at 9°, 13° and 17°C or splitted (in two halfs) at midnight (17°/12°C, 17°/9°C). Root-zone warming to 24° or 30°C increased cucumber plant growth and leaf development, but did not compensate completely the loss of productivity induced by low NAT. Split-night temperature had greater effects under the lowest NAT (17°/9°C) and at high RZT (24° or 30°C). In a third experiment, soil warming caused large increase in yields when cucumber plants were grown in the spring, but had very little effects in the fall.     

Effect ofE. coli endotoxin on temperature,oxygen consumption and brown adipose tissue thermogenesis in rats and mice

The effects ofE. coli endotoxin 0127 B8 on oxygen consumption, temperature, and on the activity of the proton conductance pathway in brown adipose tissue (BAT) were investigated in rats and mice. In rats an increase was observed in rectal and skin temperature, whole body oxygen consumption and GDP binding in BAT. In mice only the rise in rectal and skin temperature were significantly changed by endotoxin administration.These findings suggest that in some species BAT is involved in the production of endotoxin induced fever and increased energy expenditure.     

The MLA6 coiled-coil, NBS-LRR protein confers AvrMla6-dependent resistance specificity to Blumeria graminis f. sp. hordei in barley and wheat

The barley Mla locus confers multiple resistance specificities to the obligate fungal biotroph, Blumeria (= Erysiphe) graminis f. sp. hordei. Interspersed within the 240 kb Mla complex are three families of resistance gene homologs (RGHs). Probes from the Mla-RGH1 family were used to identify three classes of cDNAs. The first class is predicted to encode a full-length CC-NBS-LRR protein and the other two classes contain alternatively spliced, truncated variants. Utilizing a cosmid that contains a gene corresponding to the full-length candidate cDNA, two single-cell expression assays were used to demonstrate complementation of AvrMla6-dependent, resistance specificity to B. graminis in barley and wheat. The first of these assays was also used to substantiate previous genetic data that the Mla6 allele requires the signaling pathway component, Rar1, for function. Computational analysis of MLA6 and the Rar1-independent, MLA1 protein reveals 91.2% identity and shows that the LRR domain is subject to diversifying selection. Our findings demonstrate that highly related CC-NBS-LRR proteins encoded by alleles of the Mla locus can dictate similar powdery mildew resistance phenotypes yet still require distinct downstream signaling components.     

Effects of brief exposures to low temperature on the development, longevity and fecundity of the grain aphid Sitobion auenae (Hemiptera: Aphididae)

First instar nymphs and adults of the grain aphid Sirobion auenae that had been reared at 10°C and 20°C over a number of generations, were cooled to -5°C and -10°C for 1 h and 6 h and returned to 20°C to assess the effects of brief exposures to low temperatures (cold-pulses) on their survival. rate of development, longevity and fecundity. A strong acclimation response was observed in first instar nymphs, with significantly less mortality in groups reared to 10°C compared to 20°C. Mean development time from first instar to adult was not significantly affected by low temperature exposure at the first nymphal stage. Longevity in all groups cooled as first instars was reduced by the sub-zero cold-pulses, and was also dependent on temperature and exposure time. Acclimated aphids survived longer than non-acclimated individuals. Reproductive rate, in terms of the number of nymphs born per aphid per day, was unaffected by cold stress applied at the first instar stage. Total fecundity was however reduced, being a function of the number and longevity of the survivors. Adult aphids were less cold hardy than nymphs; mortality was higher at -10°C than -5°C increasing with duration of exposure from 1 h to 6 h. Mean fecundity was reduced significantly in aphids cooled at the adult stage, the number of aphids born per day decreasing as the exposure period of the cold-pulse increased, suggesting that low temperature had affected embryogenesis. All the nymphs born to adults surviving exposure to -5°C for 6 h died within 48 h of birth, indicating that low temperature has a pre-natal effect on mortality.     

青菜/油菜茬口下水稻栽植方式对温光资源利用和产量的影响

轻简化栽培和优质稻是当前我国水稻生产的主要方向,气象因子是对水稻生长发育和产量形成影响最大的环境因素,但在不同轻简化栽植方式下水稻产量与其田间小气候的关系鲜有研究。为探究西南地区不同前作下杂交稻各生育阶段温、光和水等气候因子与水稻产量形成的关系,在2019—2020年,以杂交籼稻‘宜香优2115'为试验材料,采用两因素裂区设计,主区为青菜和油菜2种前作,副区为机直播、毯苗机插和人工移栽3种栽植方式,研究杂交稻产量对气候因子的响应及水稻植株对温光资源的利用。结果表明: 与油菜-水稻模式相比,青菜-水稻模式下杂交稻积温生产效率和降水生产效率显著提高,进而提高了有效穗数、结实率和千粒重,2年产量分别提高了12.7%和8.3%。与人工移栽相比,机插稻提高了单位面积有效穗数、全生育期光能生产效率、积温生产效率、籽粒光能利用效率和降水生产效率,2年平均产量提高了4.6%;而机直播全生育期降水生产效率、光能生产效率、积温生产效率、籽粒光能利用效率、每穗粒数和千粒重都显著降低,导致2年平均产量下降了8.7%。与2019年相比,2020年机插稻和人工移栽稻在同一茬口下提前一个月播种造成花后生育期缩短、气温降低和降雨量增多,导致有效积温和光辐射量大幅减少,积温生产效率、光能生产效率、降水生产效率和籽粒光能利用效率以及每穗粒数、结实率和千粒重均大幅降低,进而导致产量严重降低。用偏最小二乘法回归分析建立的气象因子产量预报方程标准化回归系数显示,水稻产量与阶段生育期或全生育期内有效积温和总辐射量呈正相关关系,与全生育期内降水量呈显著负相关关系。综上,青菜-水稻模式下机插秧与西南地区稻季光温资源匹配度最高,更有利于温光资源的充分利用和获得高产,但不宜过早播种或移栽。     

埃玛菌素对小菜蛾幼虫的毒力及其对子代种群增长的影响

研究了不同温度下埃玛菌素（emamectin）对小菜蛾Plutella xylostella幼虫的毒力,并用生命表法研究了25℃下埃玛菌素亚致死剂量LC₃₀）处理小菜蛾3龄初期幼虫后对其子代的影响。结果表明,埃玛菌素为典型的正温度系数药剂,对小菜蛾幼虫的触杀毒力在温度16～31℃间提高了10倍左右,口服毒力在相同温度范围内提高1 000倍左右,显示了埃玛菌素对该虫极高的口服毒力。25℃下埃玛菌素亚致死剂量处理当代幼虫后,对其子代的存活和繁殖均有明显影响,处理组和对照组子代的世代存活率分别为3.7%和35.5%,平均产卵量分别为92.4和148.3,种群趋势指数分别为1.8和27.4,净增殖率（R₀）分别为3.66和33.81,内禀增长力（r_m）分别为0.0665和0.0978。