Diurnal Fluctuations in Growth and CO2 Exchange in Dactylis glomerata

Diurnal fluctuations in dry matter accumulation and leaf extensionof seedlings of Dactylis glomerata were followed through a 16-hlight period and a subsequent 8-h dark period at 20 °C.Themeasured increase in dry weight during the light period andthe decrease during the dark period showed a very good agreementwith calculated dry weight changes derived from the rates ofcarbon dioxide exchange of whole seedlings. Although dry weightof the leaf blades decreased during the dark period, leaf expansioncontinued throughout the 24-h period with associated changesin the ratio of fresh weight to dry weight of the leaf blades.     

半干旱雨养农业区马铃薯干物质和钾素积累与分配特性

2010年在甘肃省定西市通过大田试验,研究了半干旱雨养农业区马铃薯的干物质(DM)和钾素(K)积累与分配规律.结果表明： 马铃薯根、茎、叶的DM积累量在全生育期内呈单峰曲线,大小顺序为叶＞茎＞根;全株和块茎DM积累量在全生育期内持续增加,均呈“S”型增长曲线.全株的DM积累最大速率大于块茎,且出现时间比块茎早17 d. DM在各器官中的分配以块茎形成末期和块茎增大末期为转折点;在块茎形成末期之前,DM分配比例以叶片最大,其后以块茎最大;干质量平衡期出现在块茎增大末期(出苗后90 d左右),此期之前块茎的DM积累量小于根茎叶,二者的积累量呈正相关,其后块茎大于根茎叶,二者呈负相关.全株干物质积累主要来源于块茎.植株干物质积累量在苗期、块茎形成期、块茎增长期、淀粉积累期和成熟期的分配比例分别为5%、30%、60%、4%和1%,块茎干物质积累量的分配比例分别为0、18%、62%、18%和2%.全生育期内,马铃薯50%以上的干物质在块茎增长期形成. 马铃薯品种“新大坪”各器官中钾浓度以茎最高,块茎最低,在干质量平衡期之前根中的钾浓度高于叶,之后低于叶;各器官中钾的积累量在干质量平衡期之前集中分配在根茎叶中,表现为茎＞叶＞根,之后主要向块茎中分配和积累,至成熟期,60%以上的钾贮藏在块茎中.     

Ontogenetic differences in sensitivity to LiCl- and amphetamine-induced taste avoidance in preweanling rats

When amphetamine is associated with a tastant conditioned stimulus, rats learn to avoid the taste even when employing doses that promote conditioned place preference. One hypothesis raised to account for this effect proposes that taste avoidance induced by amphetamine may be motivated by fear. A sensitive period has been identified in the rat (until postnatal day 10) in which infants learn conditioned appetitive effects to stimuli to which aversions are conditioned after this period. Exogenous administration of corticosterone within this period reverses this effect, generating aversive conditioning. In the present study, we tested conditioning of aversions to amphetamine or LiCl, within and after the sensitive period (Experiments 1 and 2). A third experiment evaluated unconditioned rejection of an aversive quinine solution within the sensitive period. Finally, we tested whether corticosterone administration before conditioning modulates amphetamine-induced taste avoidance. After the sensitive period, infant rats rejected the solution paired with amphetamine or LiCl after 2 conditioning trials, but within the sensitive period, aversions were conditioned only by LiCl and after 4 conditioning trials. Amphetamine-induced taste avoidance was not observed even when corticosterone was administered before conditioning. Additionally, during the sensitive period, a low LiCl dose promoted conditioned taste preference. According to Experiment 3, parameters employed in this study were suitable to yield rejection of aversive solutions within the sensitive period. These results suggest that during the sensitive period, there is a notable resistance to the acquisition of taste avoidance induced by amphetamine. The present experimental framework may represent a useful tool for studying mechanisms underlying taste avoidance and aversion effects.     

Changing trends in the outpatient dental visits during the COVID – 19 pandemic in a tertiary care hospital

The coronavirus pandemic has caused a global public health crisis with an unprecedented shutdown of major establishments and non-emergency services. Disruptions across the country in dental hospitals led to challenges in addressing patient’s dental complaints. The present study aimed to analyse the difference in the pattern of the Outpatient dental visits during the pandemic period in comparison to that of the pre-pandemic period in a tertiary care hospital. This retrospective study was carried out by retrieving the patient data from the diagnostic register of the Department of Oral Medicine and Radiology for a period of one year. The data that was retrieved from 24th September 2019 to 23rd March 2020 was categorized under the pre-pandemic period and the data from 24th March 2020 to 24th September 2020 was grouped under the pandemic period. Patient data regarding the age, gender and clinical diagnosis was recorded and categorized under three main categories: “Emergency”, “urgent” and “elective”. 7550 patients during pre-pandemic period and 4035 patients during the pandemic period visited the dental hospital during the study period. Under the “emergency dental care” category, during the pre-pandemic period, majority of the cases reported of acute dental pain (71.0%) followed by cellulitis and space infection (20.1%) and maxillofacial trauma (8.7%). During the pandemic period, acute dental pain consisted of all emergency visits (n = 307). The proportion of emergency dental visits during the pandemic were significantly higher than the pre-pandemic period. Elective dental visits were significantly higher during pre-pandemic period in comparison to the pandemic period. (P < 0.001). There was a notable change in the outpatient trend of the dental visits during the COVID-19 pandemic in comparison to the pre-pandemic period. Emergency dental services were utilized at a higher rate during the pandemic period in comparison to the pre-pandemic counterpart.     

No sexual differences in embryonic period in jackdaws Corvus monedula and black-headed gulls Larus ridibundus

Offspring survival probability usually decreases with hatching order, especially in species with brood reduction. Brood reduction in combination with a sex difference in embryonic period (the time between laying and hatching of an egg) can potentially have a profound effect on sex allocation, with higher investment in chicks of the early hatching sex because they are more likely to survive to fledge. Two recent studies reported sex differences in the embryonic period, but compared embryonic period between, rather than within, clutches, which does not control for possible environmental effects on both clutch sex ratio and embryonic period. We compared the embryonic period of sons and daughters within clutches in jackdaws Corvus monedula and black-headed gulls Larus ridibundus , two species with frequent brood reduction, and found no sexual difference in embryonic period. This suggests that sex allocation is not affected by sex differences in embryonic period in these species, but more studies are required to verify whether this is a general pattern.     

棉田捕食性天敌群落动态研究

对安徽沿江棉田捕食性天敌群落动态进行了研究。结果表明,棉田捕食性天敌种类很多,共记录19种,主要优势种为龟纹瓢虫,草间小黑蛛,八斑球腹蛛,三突花蛛,小花蝽和三色长蝽,捕食性天敌数量丰富,但雨季较少,优势种中龟纹瓢虫,三突花蛛,小花蝽和三色长蝽主要分布于棉株上部和中部,草间小黑蛛和八斑球腹蛛主要分布于棉株中,下部,群落多样性在棉花生育期前期较高,7月上旬棉花蕾花期达最大值,此后不断下降,影响群落多样性的主要因子,在棉花生育前期（苗期至蕾花期）是物种丰富度,在棉花生育后期（花铃期至吐絮期）是均匀度。群落特征在8月中旬前棉花苗期至花铃期较为类似,以后群落优势种特征日益突出,群落变化显著。     

莲花期调控研究进展

莲(Nelumbo)是我国十大传统名花中唯一的水生花卉,具有很高的观赏价值及经济价值。花期是影响莲观赏价值的重要性状,花期调控对其生产和应用有着极其重要的意义。莲一般6-8月开花,但是通过花期调控,可以实现一年四季均能开花。本文针对莲花期的定义和特点、花期调控的基本原理、分子机制和调控技术等方面进行系统地综述,并对莲花期调控的前景进行展望,以期为莲花期调控的深入研究和产业发展提供参考。     

粗柄独尾草不同器官蒽醌类成分的消长规律

采用高效液相色谱法对沙生类短命植物粗柄独尾草苗期、营养生长期、初花期、盛花期、果期各器官中大黄素、大黄酚、大黄酸、芦荟大黄素含量的消长规律进行了研究。结果表明:叶中,芦荟大黄素的含量在苗期和初花期都较高,在盛花期时最低;大黄酸的含量在苗期最高,盛花期时最低;大黄素的含量在苗期达到最高,初花期和盛花期最低;大黄酚的含量也以苗期最高,盛花期和果期最低。且在初花期时,4种蒽醌类物质含量均呈现明显的叶先端>叶中部>叶基部的空间差异性。根中,芦荟大黄素的含量在苗期和营养生长期较高,而以盛花期和果期较低;大黄酸的含量在果期最高,其余时期差异不显著;大黄素的含量以苗期和初花期较高;大黄酚的含量在果期达最高,而盛花期时最低。同时期的根叶蒽醌含量相比,叶中的芦荟大黄素要高于根,而根中大黄酚含量要高于叶。同时期各器官蒽醌总量相比:叶>根>花>花葶。故若选取粗柄独尾草作为蒽醌类药材利用,建议最佳采集方式为采集初花期的叶先端部分。     

浊漳河主要污染物时空变化特征

通过对浊漳河流域 1996～ 2 0 0 0年 2 1个监测断面的枯水期 (5月 )、丰水期 (8月 )和平水期 (10月 )地表水采样分析 ,研究了其中主要污染物COD、BOD5、NH3 N、NO2 N和挥发酚的时空变化特征。结果表明 ,污染物浓度随季节变化特征较为复杂 ,但总体表现了枯水期 >平水期 >丰水期的总体特征。污染物沿程变化与各断面接纳不同来源的污染物有关。     

Individual differences in respiratory sinus arrhythmia

To investigate the interindividual differences in respiratory sinus arrhythmia (RSA), recordings of ventilation and electrocardiogram were obtained from 12 healthy subjects for five imposed breathing periods (T(TOT)) surrounding each individual's spontaneous breathing period. In addition to the spectral analysis of the R-R interval signal at each breathing period, RSA characteristics were quantified by using a breath-by-breath analysis where a sinusoid was fitted to the changes in instantaneous heart rate in each breath. The amplitude and phase (or delay = phase x T(TOT)) of this sinusoid were taken as the RSA characteristics for each breath. It was found that for each subject the RSA amplitude-T(TOT) relationship was linear, whereas the delay-T(TOT) relationship was parabolic. However, the parameters of these relationships differed between individuals. Linear correlation between the slopes of RSA amplitude versus T(TOT) regression lines and 1) mean breathing period and 2) mean R-R interval during spontaneous breathing were calculated. Only the correlation coefficient with breathing period was significantly different from zero, indicating that the longer the spontaneous breathing period the lesser the increase in RSA amplitude with increasing breathing period. Similarly, only the correlation coefficient between the curvature of the RSA delay-T(TOT) parabola and mean breathing period was significantly different from zero; the longer the spontaneous breathing period the larger the curvature of RSA delay. These results suggest that the changes in RSA characteristics induced by changing the breathing period may be explained partly by the spontaneous breathing period of each individual. Furthermore, a transfer function analysis performed on these data suggested interindividual differences in the autonomic modulation of the heart rate.     

The Mode of Flower-Inhibiting Action of Ethylene in Pharbitis nil

The inhibitory effect of ethylene on photoperiodic flower inductionin Pharbitis nil was investigated in relation to the time ofethylene application. Ethylene applied during an 18-h dark periodnot only made the dark period non-inductive, but also greatlyinhibited the flower-inducing effect of the 2nd 18-h dark periodgiven 6 h after the end of the first dark period. The seconddark period was inductive when it was given 30 h after the endof the first dark period, during which ethylene was applied.Ethylene applied during the light period prior to an inductivedark period had no inhibitory effect, suggesting that ethylenegiven during the dark period produces some flower-inhibitingentity. (Received April 17, 1987; Accepted June 17, 1987)     

Changes in body condition in breeding kittiwakes Rissa tridactyla

We investigated the seasonal pattern of changes in body condition of breeding black‐legged kittiwakes Rissa tridactyla in Svalbard (79°N) to evaluate whether changes in body condition were a consequence of the energetic demands of breeding (the reproductive stress hypothesis) or of voluntary anorexia to attain lower flight costs during chick rearing (the programmed anorexia hypothesis). Adult body condition was recorded from early egg laying to fledging and was examined in relation to date (relative to hatching), sex, parental time‐budget, brood size and reproductive success. To distinguish between the two hypotheses we evaluate whether the reduction in body condition occurred during or ahead of the energetically most demanding part of the chick‐rearing period. We combine our results on changes in body condition and time‐budget with published information on field metabolic rate (FMR) and chick energy requirements from studies in the same colony.
Our calculations of adult energy requirements and energy intakes indicate that the first part of the chick‐rearing period was energetically the most demanding period, because adult energy requirement per hour spent off the nest was highest in this period, and adults were time constrained because of the need for 24‐h brooding of the chicks.
During the incubation period female body condition increased slightly, but significantly, while male body condition was stable. During the first part of the chick‐rearing period, female and male body condition decreased by 14.8% and 8.4%, respectively. During the second part of the chick‐rearing period, both male and female body condition remained stable. The reductions in body condition occurred during the phase which was suggested to be the energetically most demanding part of the chick‐rearing period, thus supporting the reproductive stress hypothesis. Parental body condition during the incubation period was positively related to the probability of successfully fledging young, providing additional support for the reproductive stress hypothesis.     

Behavior of Lambs in Rest Pens During Long-Distance Transport

The aim of this study was to determine how one group of lambs utilized 2 consecutive rest periods in novel environments with access to food and water that occurred during 22 hr of motor transport. The 18.5 ± 0.6 kg lambs (n = 15) were transported for 8 hr and then unloaded for a 6-hr rest period. After 6 hr, the lambs were reloaded for another 8 hr of transport followed by a 24-hr rest period. Reloading for a second 8 hr of transport followed the initial rest period. The percentage of lambs engaged in drinking, eating, lying, playing, or “other” was determined at 15-min intervals. During the 6-hr rest period, peak lying behavior occurred during the 2nd and 6th hr of the period. During the first 6 hr of the 24-hr rest period, the percentage of lambs lying increased while the percentage of lambs eating decreased. In addition, the percentage of lambs lying during the first 6 hr of the 24-hr rest period was greater than during the 6-hr rest period. Lying down had a greater priority than eating during the second (24-hr) rest period.     

Seasonal changes in the concentration of plasma prolactin in the migratory Canada goose (Branta canadensis interior)

• 1.1. Seasonal changes in the plasma prolactin level of the migratory Canada goose breeding in the Canadian subarctic region (Fort Churchill, Manitoba) and wintering in the southern USA (Swan Lake Refuge, Missouri) were studied.
• 2.2. Peak prolactin level was observed in geese collected at Missouri in October, immediately after Fall migration (Fall postmigratory period). This was significantly higher than that in September (Fall premigratory period), July (moulting period) and March (Spring premigratory period).
• 3.3. Prolactin levels in May (Spring postmigratory period) and June (incubating period) did not differ significantly from that of any other period.

     

Annual changes in testicular development and occurrence of parasperm in the male reproductive organs of fourspine sculpin, Cottus kazika

Annual changes in testicular development and occurrence of parasperm were investigated using 2-year-old male fourspine sculpins Cottus kazika, based on the histological observation of testes. The male reproductive organ of fourspine sculpins comprised a pair of testes and a sperm duct that functioned as a sperm-storage organ. Male maturity was divided into the following periods: spermatogonial proliferation period (September), early spermatogenic period (October), mid-spermatogenic period (November), late spermatogenic period (December and January), functional maturation period (February and March), and recovery period (April to August). Spermatogenesis rapidly progressed from October to January and continued until the functional maturation period. Parasperm formation, which is known in some cottidae species, was observed in fourspine sculpins. Testicular regression of cultured fourspine sculpins progressed slowly during the recovery period when residual parasperm and empty spaces occupied the testis. The parasperm were immotile and oval and slightly concave on one side; additionally, they stained strongly with hematoxylin and PAS. Seminal lobules of the testis were filled with parasperm during the spawning period; in contrast, the sperm duct was filled with eusperm. These findings were observed in both cultured and wild fish. In this study, the functions of parasperm with regard to reproduction in fourspine sculpins are discussed.     

Behavior of lambs in rest pens during long-distance transport

The aim of this study was to determine how one group of lambs utilized 2 consecutive rest periods in novel environments with access to food and water that occurred during 22 hr of motor transport. The 18.5 +/- 0.6 kg lambs (n = 15) were transported for 8 hr and then unloaded for a 6-hr rest period. After 6 hr, the lambs were reloaded for another 8 hr of transport followed by a 24-hr rest period. Reloading for a second 8 hr of transport followed the initial rest period. The percentage of lambs engaged in drinking, eating, lying, playing, or "other" was determined at 15-min intervals. During the 6-hr rest period, peak lying behavior occurred during the 2nd and 6th hr of the period. During the first 6 hr of the 24-hr rest period, the percentage of lambs lying increased while the percentage of lambs eating decreased. In addition, the percentage of lambs lying during the first 6 hr of the 24-hr rest period was greater than during the 6-hr rest period. Lying down had a greater priority than eating during the second (24-hr) rest period.     

Synchronous fluctuations of LH and FSH in plasma samples collected daily during the estrous cycle in mares

Circulating concentrations of LH and FSH in each of 12 mares were measured in daily blood samples from 3 d before until 3 d after an interovulatory interval (ovulation=Day 0). The interval was normalized to its mean length (22 d) and partitioned into periods relative to high and low (first significant increase and decrease: Days 3 and 14, respectively) mean FSH concentrations. The resulting experimental periods were as follows: 1) Days −3 to 2 corresponding to the periovulatory period, 2) Days 3 to 14 corresponding to the luteal period, and 3) Days −7 to 3 corresponding to the follicular-periovulatory period. An adaptive threshold method was used to detect peak concentrations of LH and FSH fluctuations. There was no significant difference in the number of detected LH fluctuations per mare among the 3 periods (means, 1.2, 1.8, 1.6 fluctuations, respectively). However, more (P<0.05) FSH fluctuations per mare were detected during the luteal period (mean, 2.4 fluctuations) than during the periovulatory period (mean, 0.5 fluctuations) and follicular-periovulatory period (mean, 1.2 fluctuations). Synchronous LH and FSH fluctuations, defined as the simultaneous detection of peak concentrations of fluctuations, occurred more (P<0.05) often per mare during the luteal period (mean, 1.3 fluctuations) than during the periovulatory period (mean, 0.1 fluctuations) and follicular-periovulatory period (mean, 0.2 fluctuations). During the luteal period, concentrations of LH peaked (P<0.05) during FSH fluctuations and, conversely, concentrations of FSH peaked (P<0.05) during LH fluctuations, indicating a high degree of coupling between the 2 gonadotropins. In summary, fluctuations of LH and FSH occurred in synchrony with a high degree of coupling between them during the luteal period, but not during the periovulatory and follicular-periovulatory periods.     

Long term oscillation in glycolysis

To increase the period of glycolytic oscillations in yeast extracts (Saccharomyces uvarum), the dependence of the period on pH, on concentrations of phosphate and enzymes, and on temperature has been studied. Stable oscillatory trans were obtained at a pH value of about 6.5. Increasing the phosphate and decreasing the enzyme concentrations as well as decreasing temperature lengthened the period. By dilution of the extract with buffer while maintaining the metabolite concentrations at their initial level the period could be successively prolonged from 20 min to about 6 h.     

Endocrine aspects of social instability in the olive baboon (Papio anubis)

The relationships among social status and the cortisol and testosterone stress-response were studied in the non-natal male members of a troop of olive baboons (Papio anubis) before and during a period of social instability. The unstable period was characterized by dominance interactions that were more frequent, more inconsistent, and produced less linear hierarchies than during the stable period. These changes occurred predominantly among the high-ranking males. Such males engaged in coalitions and consortship harassments at a higher rate during the unstable period than during the stable period. Finally, high-ranking males had the highest rates of involvement in and initiation of escalated fighting during the unstable period, in contrast with the stable period. A number of endocrine correlates of instability emerged. During the stable period, high-ranking males (by reproductive criteria) showed an endocrine profile different from that of subordinates. They had the lowest basal cortisol titers, the largest and fastest increases in cortisol titer during stress, and had elevated testosterone titers during stress. None of these attributes was found in high-ranking males during the unstable period. Males during the unstable period had elevated basal cortisol titers, suppressed cortisol responsiveness to stress, and no longer showed elevated testosterone titers during stress. When psychological advantages associated with social status in a stable social environment were lost, endocrine efficiency previously associated with social status was apparently also lost. Further, high-ranking males, who were most aggressive exclusively during the unstable period, had the highest absolute titers of testosterone exclusively during the unstable period. Thus, elevated testosterone and high levels of aggression were unrelated to social status during the period of social stability, but were traits associated with dominant individuals during the unstable period.