亚适温和硝酸盐胁迫对黄瓜幼苗生长及镁吸收的影响

在亚适温条件(昼/夜18℃/12℃)下,研究硝酸盐胁迫1和14 d对黄瓜幼苗生长及镁吸收的影响.结果表明:亚适温条件下,硝酸盐胁迫对黄瓜幼苗生长产生显著抑制作用.与适温对照相比,其叶片的净光合速率、蒸腾速率、光系统Ⅱ最大光化学效率和实际光化学效率均明显下降;幼苗根、茎、叶中镁含量明显下降,尤以处理Ⅳ(亚适温+140 mmol·L-1 NO3-+1 mmol·L-1 Mg2+)最为显著;Mg2+对K+和Ca2+吸收有拮抗作用,增加营养液中的Mg2+浓度,可使黄瓜幼苗的缺镁症状得到缓解.     

黄瓜花期高温胁迫对叶片衰老特性和内源激素的影响

为了研究黄瓜花期高温胁迫对植株叶片衰老特性及内源激素的影响,本研究以黄瓜‘南杂2号’(Nan ZaⅡ)品种为试材,利用人工气候箱设计3个温度处理:昼温/夜温分别为36℃/26℃、39℃/29℃、42℃/32℃,以昼温/夜温24℃/18℃为对照(CK),持续时间设计1、3、5和7 d。处理完成后分别测定黄瓜叶片叶绿素含量、抗氧化酶活性、MDA含量和顶芽内源激素含量。结果表明:42℃/32℃处理7 d时黄瓜叶片叶绿素a、叶绿素b、类胡萝卜素含量,POD、SOD活性,顶芽IAA、GA3、ZT含量分别较CK降低了16.61%、23.17%、73.33%、17.89%、56.90%、94.16%、54.32%、90.68%;而叶片MDA含量、CAT活性和顶芽ABA含量分别较CK增加了62.66%、28.06%和294.35%;短期高温胁迫增加了黄瓜叶片的叶绿素含量,随着温度的升高,胁迫时间的延长叶片叶绿素b含量逐渐降低;短期高温胁迫增加了叶片抗氧化酶活性,随着高温胁迫的加剧,抗氧化酶活性表现出逐渐降低的趋势;高温胁迫下黄瓜顶芽ABA含量表现出增加的趋势,而IAA、GA3和ZT含量的变化则相反。本研究揭示了黄瓜花期高温胁迫下叶片衰老特性和内源激素含量的变化规律,为黄瓜栽培的温度管理提供科学依据。     

根际温度对黄瓜幼苗生长及生理生化指标的影响

采用营养液栽培法,以‘春秋王2号’黄瓜为实验材料,研究了4个根际温度梯度处理(20℃、25℃、30℃、35℃)对其幼苗生长,地上部、地下部生理生化指标的影响,探讨根际温度对黄瓜幼苗生长的影响机理。结果显示:(1)黄瓜幼苗的株高、茎粗、叶面积和地上地下生物量在25℃处理下都明显大于其他3个处理,而在35℃处理下均显著降低。(2)20℃、25℃处理下,黄瓜幼苗叶片的净光合速率(Pn)均较大,此时其叶片与根系中的淀粉、蔗糖、总糖含量较高且明显高于30℃处理,35℃根际温度处理下叶片Pn严重下降。(3)根际30℃、35℃高温使得黄瓜幼苗叶片和根系中的POD活性升高,CAT活性降低;而叶片中SOD、APX活性均随根际温度的升高而增大,根系中则表现出了逐渐下降趋势。(4)叶片和根系的电解质渗漏率、丙二醛(MDA)含量在25℃下最低,而在35℃处理下最高;叶片中脯氨酸及可溶性蛋白含量在35℃处理下最高,但此时根系中含量显示最低。研究表明,4个根际温度中,25℃最适合黄瓜幼苗的生长,35℃高温直接作用部位(根系)的2种主要渗透调节物质脯氨酸及可溶性蛋白含量下降,此时叶片和根系中抗氧化酶活性的变化使得细胞膜受到了明显的过氧化伤害,根系受伤害程度加重,从而抑制了植株整体的生长。     

水杨酸对高温胁迫下黄瓜幼苗叶绿素荧光参数的影响

以津春3号黄瓜为试材,对其喷施0.05、0.1和0.5 mmol/L的水杨酸(SA)溶液,并进行了昼(40±1)℃/夜(30±1)℃高温胁迫处理,研究了黄瓜幼苗四叶期叶片叶绿素荧光参数变化.结果表明,高温胁迫下幼苗叶绿素荧光参数Fo、NPQ等显著升高,Fv/Fm、Fv′/Fm′等明显降低,嫁接苗的变化趋势弱于自根苗;不同浓度的SA溶液可缓解高温胁迫对黄瓜幼苗叶绿素荧光参数的影响,且以0.1 mmol/L的SA处理效果最优.     

叶绿酸铁对亚适温条件下黄瓜幼苗渗透调节物质及抗氧化酶活性的影响

以黄瓜品种“津研四号”为试材,利用光照培养箱进行亚适温处理(昼/夜18/12 ℃),研究亚适温条件下喷施5 mg·L^-1叶绿酸铁溶液对黄瓜幼苗生长、脯氨酸、可溶性糖、丙二醛含量及抗氧化酶活性的影响.结果表明: 亚适温条件下叶面喷施叶绿酸铁可以缓解亚适温对黄瓜生长的抑制,增加叶片中脯氨酸和可溶性糖含量,减少丙二醛含量,提高超氧化物歧化酶、过氧化物酶、过氧化氢酶及抗坏血酸过氧化物酶活性.喷施叶绿酸铁在一定程度上可通过促进渗透调节物质的积累和提高抗氧化酶活性,来降低膜脂质过氧化水平,从而增强黄瓜幼苗对亚适温的适应性.     

低镁胁迫对低温下黄瓜幼苗光合特性和抗氧化系统的影响

以‘津优3号’黄瓜幼苗为试材,以Hoagland全营养液处理为对照(CK),研究低镁(30％Mg)胁迫对低温(昼/夜温度12℃/8℃)下黄瓜幼苗光合特性和抗氧化系统的影响.结果表明:低温下30％Mg处理黄瓜幼苗叶片Mg含量显著低于CK,而根中Mg含量与CK差异不显著.随着低温胁迫时间的延长,黄瓜幼苗叶片的叶绿素含量、净光合速率(Pn)、气孔导度(gs)和羧化效率(CE)逐渐降低,胞间CO2浓度(Ci)趋于升高.与CK相比,低温下30％ Mg处理叶片叶绿素含量、Pn、gs和CE显著降低,C-变化不大,叶绿体膜损伤严重,叶绿体数、基粒数和片层数较少,淀粉粒数增加,淀粉粒较长,丙二醛(MDA)含量升高,而超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性降低.可见,低温下镁运输受阻引起的缺镁是叶片失绿的主要原因;低温引起Pn降低的主要原因是非气孔限制,低镁胁迫会加大低温对黄瓜Pn的影响,而由此引起的Pn降低的主要原因是气孔限制.     

白蜡虫阔柄跳小蜂实验种群生命表的研究

观察了温度对白蜡虫阔柄跳小蜂（Metaphycus ericeri Xu et Jiang）存活和繁殖的影响,组建了18℃、21℃、24℃、27℃、30℃和33℃6种温度下的实验种群生命表,白蜡虫阔柄跳小蜂的世代存活率为24℃＞27℃＞30℃＞21℃＞33℃＞18℃＞15℃,温度过高或过低对白蜡虫阔柄跳小蜂的存活和繁殖不利,24℃和27℃雄虫的怀卵量、产卵量和产卵百分率都显著高于其它温度处理,以抛物线方程y=a bx cx^2拟合世代存活率（S）、种群趋势指数（I）、净生殖率（R0）和内禀增长为（rm）,在24℃、27℃和30℃温度下,白蜡门阔柄跳小蜂的种群趋势指数I＞1,内禀增长力rm＞0,种群数量逐代增加,种群加倍时间分别为15、16和23d,21℃时I≈1,rm≈0,种群数量基本保持不变,18℃和33℃时I＜1,rm＜0,种群数量出现负增长,15℃雌蜂不产卵,不能繁殖后代。     

不同温度对迷人杜鹃种子萌发与幼苗生长及生理特性的影响

该研究利用实验室不同恒温和变温控制试验,考察了不同温度[恒温(15℃、25℃、35℃)和变温(25℃/15℃、30℃/20℃,高温12 h,低温12 h)]处理对迷人杜鹃种子萌发、幼苗形态指标和生理生化指标的影响,探讨温度对迷人杜鹃种子萌发和幼苗生长的影响机制。结果表明:(1)迷人杜鹃种子在25℃/15℃变温条件下萌发率(87.69%)和萌发指数(8.65)均最高。(2)25℃/15℃变温有利于迷人杜鹃幼苗的地径、苗高、平均根长和萌枝数的增加,以及根、茎、叶生物量的积累。(3)25℃/15℃变温处理下幼苗叶片的总叶绿素、可溶性糖和可溶性蛋白含量最高,而MDA含量、CAT活性和SOD活性较低。研究认为,迷人杜鹃种子萌发和幼苗生长的最适宜温度条件为25℃/15℃(昼/夜),而在高温(35℃)和低温(15℃)环境下均会受到显著抑制。     

高温胁迫下番茄幼苗对冷激的响应

高温逆境是影响夏秋季蔬菜设施集约化育苗质量的主要因素之一,利用温度逆境诱导植物产生交叉适应是植物获得抗逆性的一种有效手段.为探索冷激强度对番茄幼苗高温胁迫的缓解效应,试验采用人工气候箱模拟夏季设施中的高温胁迫,研究了不同冷激温度(5、10、15 ℃)和冷激持续时间(10、20、30 min)对番茄幼苗生长、生物膜保护系统的影响,并研究了单次适宜冷激处理对番茄小分子热激蛋白LeHSP23.8和CaHSP18基因表达的影响.结果表明： 在高温胁迫前对番茄幼苗进行冷激处理可以抑制其下胚轴的伸长和株高的生长.冷激缓解番茄幼苗高温胁迫的效应在不同冷激温度下表现出不同的变化趋势;5 ℃冷激处理抑制了番茄幼苗抗氧化酶活性的升高,使细胞膜透性增大,对幼苗产生伤害;10 ℃冷激处理对番茄幼苗高温胁迫的缓解效应随冷激时间的延长呈降低趋势;而15 ℃冷激处理缓解番茄幼苗高温胁迫的效应随冷激时间的延长呈增加趋势.适宜冷激温度和冷激持续时间能够诱导番茄幼苗对高温逆境的交叉适应性,在高温胁迫前将番茄幼苗进行温度为10 ℃、持续10 min的冷激处理效果最佳,与对照相比,显著提高了高温胁迫下番茄幼苗植株单株干质量和壮苗指数,降低了番茄幼苗叶片相对电导率和丙二醛含量,促进了脯氨酸和可溶性蛋白的积累,提高了番茄幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT) 3种抗氧化酶活性,并诱导了小分子热激蛋白基因LeHSP23.8和CaHSP18在常温条件下的上调表达.
     

不结球白菜表皮蜡质高温胁迫生理响应

为了明晰高温胁迫下表皮蜡质在不结球白菜生理响应中的保护作用,该研究以不结球白菜有蜡(Q28)和无蜡(Q1202)品种为试验材料,设置高温胁迫组(昼/夜温度为37℃/30℃)和对照组(昼/夜温度为25℃/18℃)处理,观察不同材料叶片表皮细胞形态,比较分析高温胁迫处理下不同时期生理和光合指标变化的差异.结果 表明:(1)...     

Varying patterns of protein synthesis in bread wheat during heat shock

High temperatures during seedling growth are considered as one of the factors that can modify surviving properties in wheat (Triticum aestivum L.) plant. This work attempts to evaluate the heat shock responses of seedling of winter wheat (Bezostaya-1) using growth parameters (seedling length, embryonal root length and embryonal root number), membrane stability index (MSI) and two dimensional (2D) gel electrophoresis analysis of heat shock proteins (HSPs) during heat shock. Seedlings grown until first leaf opening at controlled conditions (23 degrees C, 200 micromol m(-2) s(-1), 16h day/8h night, 50-60% humidity) were exposed to 37 degrees C or 45 degrees C high temperatures for 2, 4 and 8 hours. While 37 degrees C did not cause any significant change, 45 degrees C heat treatments caused significant decrease in terms of seedling and root length, and leaf MSI for all exposure times. However, all the plants from 45 degrees C heat treatments continued to grow during recovery period. 2D protein analysis indicated that 37 degrees C, 8 hours exposure caused stronger and more diverse heat shock response than the other treatments, followed by 37 degrees C, 4 hours, 45 degrees C, 8 hours, 45 degrees C, 4 hours, 45 degrees C, 2 hours treatments. 5 protein spots, ranging from 6-7.8 pl (isoelectric point) and 27-31.7 kDA molecular weight, were expressed at 37 degrees C, 2 hours and continued at 37 and 45 degrees C for all exposure times. This suggests that these early proteins and other newly synthesized proteins may have protective effects at 37 and 45 degrees C and provide plants for healthy growth during the recovery period.     

EFFECTS OF DAY AND NIGHT TEMPERATURE AND TYPE OF CONTAINER ON THE GROWTH OF F1 HYBRID ANNUALS IN CONTROLLED ENVIRONMENTS

The effects of three day/night temperatures (18/12 C, 24/18 C, and 30/24 C), and two types of containers (clay and plastic) on the seedling growth of three F₁ hybrid annuals were determined after 14 days of controlled-environment treatment. A day/night temperature of 18/12 C was severely limiting to the early seedling growth of ‘Blue Blazer’ ageratum (Ageratum houstonianum Mill.), ‘Pink Cascade’ petunia (Petunia hybrida Vilm.), and ‘Double Eagle’ marigold (Tagetes erecta L.). Raising the day/night temperature to 24/18 C resulted in striking increases in growth in both clay and plastic pots. Fresh and dry weights of tops for all three species were increased four- to fivefold, and leaf areas of ageratum and petunia were increased more than fivefold irrespective of container. Height and node number were also increased significantly but to a much lesser degree. A day/night temperature of 30/24 C appeared to be optimum for early seedling growth of F₁ hybrid annuals the optimum being based on dry matter accumulation, stem elongation, node development, and leaf area production. Growth of lateral shoots was greatly stimulated at 30/24 C, especially in marigold. There were no appreciable differences in fresh or dry weight of tops or in leaf area between plants in clay and plastic containers at any of the three day/night temperatures.     

Confirmation and efficacy tests against codling moth and oriental fruit moth in peaches and nectarines using combination heat and controlled atmosphere treatments

Two high-temperature, forced air treatments under controlled atmosphere conditions, called CATTS for controlled atmosphere/temperature treatment system, were developed for control of all life stages of codling moth, Cydia pomonella (L.), and oriental fruit moth, Grapholita molesta (Busck), infesting peaches and nectarines (both Prunus spp.). These treatments were used in efficacy and confirmation tests to kill > 5,000 fourth instar oriental fruit moths and > 30,000 fourth instar codling moths with zero survivors. The treatments consist of linear heating rates of either 12 or 24 degrees C/h to a final chamber temperature under a 1% O2, 15% CO2, and > 90% RH atmosphere with air speed between 1.2 and 2.0 m/s. At a 12 degrees C linear chamber heating rate, treatment takes approximately 3 h to reach a final chamber temperature of 46 degrees C. The average lowest core temperatures of the fruit reached 43.8 degrees C within the last 30 min of the treatment. At a 24 degrees C linear chamber heating rate, it takes approximately 2.5 h to reach a final chamber temperature of 46 degrees C. The average lowest core temperatures of the fruit reached 44.6 degrees C for the last 15 min of the treatment. It also was determined that both treatments did not significantly alter the quality parameters that were evaluated to a degree that would have negatively influenced the marketability of the fruit. Positive benefits of treatment included a slower ripening of treated fruit and an inhibition of the loss of juiciness during storage in some cultivars. These treatments may be used to replacement to methyl bromide fumigation for conventional fruit or as a new treatment for organic fruit contingent upon importing country approval.     

Phenotypic responses of hatchlings to constant versus fluctuating incubation temperatures in the multi-banded krait, Bungarus multicintus (Elapidae)

Most studies on egg incubation in reptiles have relied on constant temperature incubation in the laboratory rather than on simulations of thermal regimes in natural nests. The thermal effects on embryos in constant-temperature studies often do not realistically reflect what occurs in nature. Recent studies have increasingly recognized the importance of simulating natural nest temperatures rather than applying constant-temperature regimes. We incubated Bungarus multicintus eggs under three constant and one fluctuating-temperature regimes to evaluate the effects of constant versus fluctuating incubation temperatures on hatching success and hatchling phenotypes. Hatching success did not differ among the four treatments, and incubation temperature did not affect the sexual phenotype of hatchlings. Incubation length decreased as incubation temperature increased, but eggs incubated at fluctuating temperatures did not differ from eggs incubated at constant temperatures with approximately the same mean in incubation length. Of the hatchling phenotypes examined, residual yolk, fat bodies and locomotor performance were more likely affected by incubation temperature. The maximal locomotor speed was fastest in the fluctuating-temperature and 30 degrees C treatments and slowest in the 24 degrees C treatment, with the 27 degrees C treatment in between. The maximal locomotor length was longest in the fluctuating-temperature treatment and shortest in the 24 degrees C and 27 degrees C treatments, with the 30 degrees C treatment in between. Our results show that fluctuating incubation temperatures do not influence hatching success and hatchling size and morphology any differently than constant temperatures with approximately the same mean, but have a positive effect on locomotor performance of hatchlings.     

Day and night temperature responses in Arabidopsis: effects on gibberellin and auxin content,cell size,morphology and flowering time

The effect of 16 different day (DT) and night (NT) temperature combinations (DT and NT 12, 17, 22 and 27 degrees C) on rosette leaf growth, flower stem elongation and flowering time in Arabidopsis thaliana Ler was investigated. Final leaf length decreased with increasing NT due to a combination of reduced elongation period and reduced elongation rate. Final stem length increased with increasing DT due to increased elongation rate, and decreased with increasing NT due to a decrease in elongation period. Under NT 27 degrees C, however, stem elongation rate increased greatly, resulting in the same final stem length as under NT 12 degrees C. The transition to flowering was accelerated by increasing NT. A linear regression analysis was performed to clarify the relationship between final leaf length, final stem length and flowering time with DIF (DT minus NT) and/or ADT (average daily temperature). For all three variables, the effect of DIF depended on ADT and vice versa. The relationship of final stem length with DIF also depended on the temperature range. Increased cell volume in flower stems developing at DT/NT 22/12 degrees C gave rise to longer and thicker stems compared with stems developing at DT/NT 12/22 degrees C. GC-MS analysis (gas chromatography-mass spectrometry) showed that the endogenous level of IAA was 56 % higher in stems grown under DT/NT 22/12 degrees C compared with DT/NT 12/22 degrees C. Of the 12 gibberellins analysed, however, only the level of non-bioactive GA29 was affected by the temperature treatment.     

The effects of temperature and swimming speed on instantaneous fuel use and nitrogenous waste excretion of the Nile tilapia.

The effects of acclimation temperature (30 degrees, 20 degrees, and 15 degrees C) and swimming speed on the aerobic fuel use of the Nile tilapia (Oreochromis niloticus; 8-10 g, 8-9-cm fork length) were investigated using a respirometric approach. As acclimation temperature was decreased from 30 degrees C to 15 degrees C, resting oxygen consumption (Mo2) and carbon dioxide excretion (Mco2) decreased approximately twofold, while nitrogenous waste excretion (ammonia-N plus urea-N) decreased approximately fourfold. Instantaneous aerobic fuel usage was calculated from respiratory gas exchange. At 30 degrees C, resting Mo2 was fueled by 42% lipids, 27% carbohydrates, and 31% protein. At 15 degrees C, lipid use decreased to 21%, carbohydrate use increased greatly to 63%, and protein use decreased to 16%. These patterns at 30 degrees C and 15 degrees C in tilapia paralleled fuel use previously reported in rainbow trout acclimated to 15 degrees C and 5 degrees C, respectively. Temperature also had a pronounced effect on critical swimming speed (UCrit). Tilapia acclimated to 30 degrees C had a UCrit of 5.63+/-0. 06 body lengths/s (BL/s), while, at 20 degrees C, UCrit was significantly lower at 4.21+/-0.14 BL/s. Tilapia acclimated to 15 degrees C were unable or unwilling to swim. As tilapia swam at greater speeds, Mo2 increased exponentially; Mo2min and Mo2max were 5.8+/-0.6 and 21.2+/-1.5 micromol O2/g/h, respectively. Nitrogenous waste excretion increased to a lesser extent with swimming speed. At 30 degrees C, instantaneous protein use while swimming at 15 cm/s ( approximately 1.7 BL/s) was 23%, and at UCrit (5.6 BL/s), protein use dropped slightly to 17%. During a 48-h swim at 25 cm/s (2.7 BL/s, approximately 50% UCrit), Mo2 and urea excretion remained unchanged, while ammonia excretion more than doubled by 24 h and remained elevated 24 h later. These results revealed a shift to greater reliance on protein as an aerobic fuel during prolonged swimming.     

Biology and thermal requirements of Trichogramma atopovirilia Oatman & Platner (Hymenoptera: Trichogrammatidae) parasitizing eggs of Diaphania hyalinata L. (Lepidoptera: Pyralidae)

The development and parasitism of Diaphania hyalinata L. eggs by Trichogramma atopovirilia Oatman & Platner and its thermal requirements were studied at the temperatures of 18, 21, 24, 27, 30 and 33 degrees C. Thirty eggs of D. hyalinata were exposed to three females of T. atopovirilia for 5h at 25 degrees C and incubated at the different temperatures. The developmental time from egg exposure to adult, parasitism viability, number of adults per parasitized host egg and progeny sex ratio were monitored. The developmental time from egg to adult emergence of the parasitoid exhibited inverse relationship to the temperature, lasting 24.12 days at 18 degrees C and 7.36 days at 33 degrees C. Parasitism viability at 24, 27 and 30 degrees C was higher than 90%. The ratio of T. atapovirilia adult produced per egg and its sex ratio were not affected when using D. hialynata as host. The lowest threshold temperature (Tb) and estimated degree-days over Tb required by T. atopovirilia to develop on eggs of D. hyalinata was 11.99 degrees C and 130.42 masculine C, respectively. Considering the temperature regimes of two areas where cucurbitaces are cultivated in Bahia State (Rio Real and Inhambupe County) it was estimated that T. atopovirilia can achieve more than 32 generation per year. The results suggest that T. atopovirilia has potential to control D. hyalinata eggs with better chance of success under temperature regimes ranging from 24 to 27 degrees C that meets the suitable field conditions for cropping cucurbitaces.     

Effects of temperature and photoperiod on vegetative growth of white clover (Trifolium repens) ecotypes

Effects of photoperiod and temperature on vegetative growth of seedling populations and clones of white clover ( Trifolium repens L.) originating from various latitudes (58°48'–69°54'N) and altitudes (up to 1100 m above sea level) were studied in a phytotron. Dry matter production, stolon elongation, petiole elongation and leaf lamina size were enhanced by long photoperiod. The requirement for long photoperiod increased with decreasing temperature. At 6°C the maximum growth was recorded under 24-h daylength. At 18°C already an increase in photoperiod from 12 to 15 h significantly enhanced growth, and maximum growth was obtained at 21-h photoperiod. The studied populations responded similarly to daylength, and the results did not indicate photoperiodic ecotypes in the material. The southernmost clones and populations generally had the highest dry matter production at all temperature treatments (6–18°C). Variation between clones within one location was, however, significant, and rapidly growing clones were found also in high-latitude locations. Dry matter production was poorly correlated with the morphological characters observed, but in some cases significant correlation with leaf lamina size was found.     

Olive fruit fly (Diptera: Tephritidae) in California: longevity, oviposition, and development in canning olives in the laboratory and greenhouse

The biology of olive fruit fly, Bactrocera oleae (Rossi), was studied in the laboratory, greenhouse, and in canning olives, Olea europaea L., in relation to California regional climates. Adults survived in laboratory tests at constant temperatures and relative humidities of 5 degrees C and 83%; 15 degrees C and 59%; 25 degrees C and 30%; and 35 degrees C and 29% for 15, 6, 3, and 2 d without provisions of food and water and for 37, 63, 25, and 4 d with provisions, respectively. In a divided greenhouse, adults survived for 8-11 d in the warm side (36 degrees C and 31% RH daytime); and in the cool side (26 degrees C and 63% RH daytime) 10 d without provisions and 203 d with provisions. A significantly greater number of adults survived in the cool side than the warm side, and with provisions than without. First and last eggs were oviposited in olive fruit when females were 6 and 90 d old, respectively. The highest number of eggs was 55 per day in 10 olive fruit oviposited by 10 28 d-old females, with maximum egg production by 13-37 d-old females. A significantly greater number of ovipositional sites occurred in all sizes of immature green fruit when exposed to adults in cages for 5 d than 2 d. Adults emerged from fruit with a height of > or = 1.0 cm or a volume of > or = 0.2 cm3. More than seven adults per 15 fruit emerged from field infested fruit with a height of 1.1 cm and volume of 0.1 cm3. Larval length was significantly different among the first, second, and third instars and ranged from 0.7 to 1.6, 2.4-4.3, and 4.8-5.6 mm at 14 degrees C; 0.8-1.1, 1.9-2.9, and 3.9-4.4 mm at 21 degrees C, and 0.7-1.3, 2.4-2.9, and 4.4-4.8 mm at 26 degrees C, respectively. Survival of pupae to the adult stage was significantly lower at 26 degrees C than 14 degrees C or 21 degrees C. The period of adult emergence began at 38, 14, and 11 d over a period of 8, 5, and 1 d at 14, 21, and 26 degrees C, respectively. Findings were related to the occurrence and control of California olive fruit fly infestations.     

The Use of Detached Seedling Leaves of Triticum aestivum to Study Pathogenicity in Puccinia recondita f. sp. tritici

A method is described for establishing isolates of Puccinia recondita f. sp. tritici (causal agent of brown rust of wheat) on detached seedling leaf segments. The method was used to compare the responses of leaf segments and intact seedling leaves for 28 differential genotypes inoculated with eight rust isolates. Leaf segments were incubated at two post-inoculation temperatures (17 and 23C) and intact seedlings at 20–25 C. Reliable determinations of isolate pathogenicity was obtained using detached leaf segments of wheats with genes Lr l. Lr2a, Lr3a, Lr3bg., Lr3ka, Lr9, Lr15, Lrl9. Lr20, Lr24, Lr25. Lr26, Lr28, and Lr30 at both post-inoculation temperatures, and for wheats with genes Lr2b. Lr2c, Lrl7, Lr23, Lr27 + Lr31 and LrH, at 23°C. Differences between leaf segments and intact leaves for the remaining eight differentials were attributed to inconsistent or poor expression of genes in detached leaf segments. By repeating tests with detached leaf segments, it was possible to establish the pathogenicities of the isolates on all of these differentials except those carrying Lr13, Lr14a, Lr16 and Lr18. Potential uses and limitations of the technique in studies of Puccinia recondita f. sp. tritici are discussed.