The Overwintering Capability of Ulva prolifera Spores and Gametes in the Yellow Sea,China

Green tides caused by the bloom of Ulva prolifera have affected the Yellow Sea annually since 2007.To explore the intrinsic causes of successive blooms,field investigations and indoor simulation experiments were conducted using micro-propagules of U.prolifera.From January to February 2014,micro-propagules of various green algae,including U.prolifera,Ulva flexuosa,and Ulva linza,were prevalent in the coastal waters of Rudong,Lianyungang,and Qingdao.However,in March 2014,micro-propagules of U.prolifera were not detected in the coastal waters of Lianyungang and Qingdao.Neither the spores nor gametes of U.prolifera can germinate at temperatures below 5℃.At 2℃and 5℃,U.prolifera spores and gametes could survive for 1-3 months at a light intensity range of 0-30μmol m^(-2)s^(-1)and for less than 1 month if the light intensity exceeded 30μmol m^(-2)s^(-1).By integrating indoor experiments and field investigations,this study found that U.prolifera spores and gametes could overwinter in the Rudong coastal area,which is an important factor for the annual emergence of recurring green tides in the Yellow Sea.

Comparison of Different Cultivars of Blueberry Overwintering Ability in Qingdao of China

In order to select severe overwintering abilitied blueberry cultivars for cold resistance of annual branches, promoting breeding high quality cultivars, a study had been conducted into field-planting shoots overwintering ability and the relative conductivity, MDA content, SOD of 7 different kinds of blueberries under artificial cooling process. According to survey results, under field conditions, Different cultivars of blueberries showed significantly difference, ranging from 56.67% of Bluegold to 12.80% of Darrow. With the temperature decreasing, changes of relative conductivity, MDA content and SOD in annual branches had a strong regularity and the hardiness of these cultivars is: Northland > Chippewa > Coville > Bluecroup > Darrow > Bluegold > Powderblue.

The mechanism underlying overwintering death in poplar:the cumulative effect of effective freeze-thaw damage

We analyzed the relationships linking overwintering death and frost cracking to temperature and sunlight as well as the effects of low temperatures and freeze–thaw cycles on bud-burst rates,relative electrical conductivity,and phloem and cambial ultrastructures of poplar.Overwintering death rates of poplar were not correlated with negative accumulated temperature or winter minimum temperature.Freeze–thaw cycles caused more bud damage than constant exposure to low temperatures.Resistance to freeze–thaw cycles differed among clones,and the budburst rate decreased with increasing exposure to freeze–thaw cycles.Cold-resistant clones had the lowest relative electrical conductivity.Chloroplasts exhibited the fastest and the most obvious reaction to freeze–thaw damage,whereas a single freeze–thaw cycle caused little damage to cambium ultrastructure.Several such cycles resulted in damage to plasma membranes,severe damage to organelles,dehydration of cells and cell death.We conclude that overwintering death of poplar is mainly attributed to the accumulation of effective freeze–thaw damage beyond the limits of freeze–thaw resistance.

Identification of Quantitative Trait Locus for Overwintering Germinability in Rice(Oryza sativa L.)

312 recombinant inbred lines （RILs） in F9 from a cross between a overwintering cold-tolerant germplasm resource Glutinous rice 89-1（Gr 89-1） and a cold-sensitive variety Shuhui 527 was used for quantitative trait locus （QTL） analysis. The scores of percent ratooning germinability （PRG） and overwintering germinability （POG） were evaluated. The overwintering germination rate of axillary buds was scored to represent the overwintering germinability. Two significant QTLs （qPRG-4 and qPRG-7） on chromosomes 4 and 7 were detected and explained 8.3 and 7.2% of the total phenotypic variation, respectively. Three significant QTLs （qPOG-2, qPOG-3 and qPOG-7） were identified and mapped on chromosomes 2, 3, and 7, respectively. These QTLs contributed 9.6, 6.7, and 17.8% of phenotypic variations, respectively. A comparative analysis using SSR markers closely linked to the three QTLs for the overwintering revealed cold-tolerant individuals, which harbour the Glutinous rice 89-1 alleles at RM7110, RM250, RM418, and RM232, had a high percent overwintering germinability, while cold-sensitive individuals, which carry Shuhui 527 alleles at these loci, had a low percent overwintering germinability in the F2 population of Shuhui 527/Glutinous rice 89-1. This study demonstrated the utility of these SSR markers for selection of overwintering germinability genotypes.

Foraging habitat selection of overwintering Black-necked Cranes in the farming area surrounding the Caohai Wetland, Guizhou Province, China

Background: Understanding how overwintering birds choose foraging habitats is very important for conservation management. The overwintering Black-necked Crane(Grus nigricollis) feeds on crop remains in farmlands;thus, reasonable conservation management of this type of farmland that surrounds wetlands is critical for the overwintering populations of the Black-necked Crane;however, it is not clear how the Black-necked Crane chooses the foraging land in the farmland.Methods: A thorough field positioning survey of all foraging sites in farmland areas around the Caohai Wetland and a-sampling analysis of habitat selection by the Black-necked Crane were conducted during the winters from 20162017 and 2017-2018.Results: Multiple factors contributed to the selection of foraging habitat in farmlands, i.e., food factors(crop remains and tillage methods) > human disturbance factors(distance to road and settlement) > topography factors(slope aspect), listed according to the strength of influence. Additionally, Black-necked Cranes tend to choose farmland sites where there was no machine tillage, the crop remains were > 500 g/m^2, the distance to residences ranged from 100 to 500 m, the distance to roads ranged from 50 to 100 m, and the slopes exhibited western or eastern aspects. As the winters progressed, the volume of the edible crop remains declined, and the influences of the other main factors also changed, i.e., the factors of human disturbance(distance to road and settlement) became less important, while the effect of the food factor(crop remains) was strengthened. Thus, the foraging sites near the road became more important.Conclusion: The farming area surrounding the Caohai Wetland is very important for the overwintering Black-necked Crane. Food factors and human disturbance factors are the main factors that influence the choice of feeding ground.

Genetic Analysis on Overwintering Character of Glutinous Rice 89-1

This article discusses the overwintering ability and genetic variation of the main agronomic traits in a new germplasm resource, glutinous rice 89-1. Survival rates of overwintering axillary buds and stems were observed in different altitudes. The F1, backcross F1 and F2 populations were constructed from sexual crossing between glutinous rice 89-1 and Hongmangnuo, Fuhui 838, Minghui 63, Ce 64. The overwintering ability and genetic variation of the main agronomic traits were analyzed in different seasons. Results showed that glutinous rice 89-1 could overwinter by axillary buds in low temperatures at different altitudes. Axillary buds would ratoon in the following year. The survival rates of rice stem and axillary buds were 82.6 and 29%, respectively. The grain yields were 6 291.0 kg ha^-1 in the overwintering ratooning season, and corresponded in the main season. Genetic analysis and chi-square test showed that the overwintering ability of glutinous rice 89-1 was likely controlled by polygene, and heritabilities showed diversity in different hybrid combinations. The highest heritabilities of 1 000-grain weight and plant height were in the main crop season, whereas the lowest were in the overwintering season, and the heritabilities of grain numbers per panicle and the seed setting rate reached the highest in the ratooning season. The spikelets per panicle, the seed setting rate, the 1 000-grain weight, the plant height, and the spikelet length had nearly normal distribution in F2 populations of glutinous rice 89-1/Minghui 63, but the seed setting rate had bimodal distribution. Overwintering glutinous rice 89-1 was a useful new genetic germplasm resource.

Overwintering of Rana dybowskii in Northern Guangdong′s Mountainous Areas

[ Objective] To understand the overwintering of Rana dybowskii under four overwintering modes in northern Guangdong＇s mountainous areas. [Method] The overwintering management of Rana dybowskii was performed under four overwintering modes which were outdoor overwintering in water-land, outdoor overwintering in water, indoor overwintering in dryness, and indoor overwintering in freezer, respectively. The time, temperature and overwintering status were recorded. The Rana dybowskii in each group was weighed before and after overwintering, and the body weight loss and the survival rate were calculated. [ Result] Under the outdoor overwintering in water-land, outdoor overwintedng in water, indoor overwintering in dryness, and indoor overwintering in freezer, the survival rate of Rana dybowskii was 40.0%, 41.5%, 82.0% and 84.5%, respectively. [Conclusion] The temperature, overwintering mode and fatness are the important factors affecting the safe overwintering of Rana dybowskii in northern Guangdong.

Genetic Analysis of Cryotolerance in Cotton During the Overwintering Period Using Mixed Model of Major Gene and Polygene

The joint analysis of the mixed genetic model of major gene and polygene was conducted to study the inheritance of cryotolerance in cotton during the overwintering period.H077（G.hirsutum L.,weak cryotolerance） and H113（G.barbadence L.,strong cryotolerance） were used as parents.Cryotolerance of six generation populations including P1,P2,F1,B1,B2,and F2,from each of the two reciprocal crosses H077×H113 and H113×H077 were all investigated.The results showed that cryotolerance in cotton during the overwintering period was accorded with two additive major genes and additivedominance polygene genetic model.For cross H077×H113,the heritabilities of major genes in B1,B2,and F2 were 83.62,76.84,and 90.56%,respectively;and the heritability of polygene could only be detected in B2,which was 7.76%.For cross H113×H077,the heritabilities of major genes in B1,B2,and F2 were 67.42,68.95,and 83.40%,respectively;and the heritability of polygene was only detected in F2,which was 6.51%.In addition,the whole heritability in F2 was always higher than that in B1 and B2 in each cross.Therefore,for the cryotolerance breeding of perennial cotton,the method of single cross recombination or single backcross should be adopted to transfer major genes,and the selection in F2 would be more efficient than that in other generations.

Effects of Overwintering on the Survival and Vector Competence of Aedes albopictus in the Urban Life Cycle of Dengue Virus in Guangzhou,China

The Pearl River Delta,where Aedes albopictus(Ae.albopictus)is the only vector for dengue transmission,has exhibited one of the highest dengue burdens in southern China in recent decades.However,whether dengue virus(DENV)can overwinter in Ae.albopictus in the Pearl River Delta has not been determined to date.In this study,300 field-derived Ae.albopictus mosquitoes from Guangzhou that were infected with the predominant endemic DENV-1 strain were investigated under simulated urban balcony environment from October 16,2016,to June 16,2017.The vertical transmission of DENV in the infected overwintering Ae.albopictus was analyzed.The DENV infected overwintering mosquitoes were evaluated for viral load at nine-time points using reverse transcription-quantitative PCR.The vector competence of the infected overwintering Ae.albopictus was also investigated by using suckling mice.Adult mosquitoes and larvae were found during the observation period.The vertical transmission of DENV-1 was documented.The DENV-1-positive rates between overwintering males and females had no difference.The proportion of DENV-1-positive overwintering mosquitoes decreased over time and had no difference beyond three months after the experiment.Overwintering mosquitoes can spread DENV-1 to hosts.No engorged mosquitoes at an ambient temperature below 15℃were observed.The ratio of engorged mosquitoes was positively correlated with the ambient temperature ranging from 15 to 30℃.Our results demonstrated that DENV can overwinter in Ae.albopictus in the Pearl River Delta,Ae.albopictus is the competent vector for DENV,and maintain autochthonous dengue outbreaks in the Pearl River Delta through vertical transmission.

Modeling of the overwintering distribution of Puccinia striiformis f.sp.tritici based on meteorological data from 2001 to 2012 in China

Wheat stripe rust caused by Puccinia striiformis f.sp.tritici occurs widely in China and seriously affects wheat production.Global warming could profoundly impact the incidence and prevalence of lowtemperature diseases such as stripe rust.Studies on the effects of temperature on the distribution of overwintering stripe rust could help us understand the incidence and prevalence of the disease and could also provide support for monitoring,forecasting and developing control strategies.An exponential model and a spherical model of the ordinary Kriging method in the ArcGIS platform were used to predict the overwintering regions of stripe rust based on the probability that the average temperature of the coldest month from December to February was higher than–6 or–7°C from 2001 to 2012.The results showed that the areas with a probability between 70%and 90%were transition regions for the overwintering of stripe rust.Based on annual mean temperature of the coldest month from December to February for 2001 to 2012,overwintering distribution of stripe rust was likewise evaluated.The boundary for overwintering of stripe rust was consistent with the areas where the probability was predicted to be 70%to 90%for the overwintering distribution of stripe rust,but the boundary was shifted northward toward Beijing in North China.Some areas in Xinjiang,including Akto,Pishan,Hotan and Yutian,were also predicted to be suitable for the overwintering of stripe rust.

Reproductive potential of field-collected overwintering boll weevils （Coleoptera： Curculionidae） fed on pollen in the laboratory

The reproductive potential of overwintering boll weevil, Anthonomus grandis grandis （Boheman）, females collected from pheromone traps in September, November and January, fed for 1, 3, and 5 weeks on plant pollens, and then provided cotton squares, was determined in the laboratory at 27 ~ I^C, 65% RH, and a photoperiod 13 ： 11 （L ： D） h. Duration of pollen feeding by overwintering boll weevils did not significantly influence egg and feeding punctures, or puncture ratios （egg to total punctures） for any of the three months of parent weevil collections when provided cotton squares on a daily basis. However, punctures and puncture ratios are significantly different when comparing mean data between months of boll weevil collections. When boll weevils were provided with cotton squares daily, the pre-ovipositional periods of female parents captured in September, November and January were 5, 9 and 14 days, respectively. The rate of eggs by females was significantly lower during November and January than September. Female parents collected in September produced a significantly higher percentage of eggs yielding adult progeny than those collected in November and January. Life table parameters indicated that net reproductive rate （Ro） of boll weevil females collected in September was 1.2- fold higher than those collected in November and 10.7-fold higher than those collected in January. Except for testes size, no differences in male reproductive parameters were observed during the cotton-free period compared with males captured during mid-cotton （June）. The number of oocytes in the ovarioles and the number of ooeytes containing yolk were significantly lower during September, November and January compared with June. The reproductive potential ofoverwintering boll weevil females collected in different months is an important consideration in determining the success of any control strategy.

Sex-speciffc selective effect of winter weather on morphological traits in a small passerine bird

Harsh environmental conditions often impose strong selection on the phenotype of natural populations through impacts on their fitness.For overwintering birds,winter is an important period for survival because the weather conditions in winter is usually severer than in other seasons and birds often suffer more thermoregulation costs while food is in short supply.Thus,the selective effect of weather conditions on phenotype in winter is expected to be strong.In this study,we examined the relationship of overwinter survival of Silver-throated Tits(Aegithalos glaucogularis)with their morphological traits under different levels of winter conditions(winters with and without snowstorms)to explore the differential selective effect of winter weather on their morphology.We found that regardless of whether the winter experienced a snowstorm,the female Silver-throated Tits with a smaller bill surface area or smaller bill depth and a smaller surface area:volume ratio were more likely to survive during the winter,which supported the hypothesis of selection for heat retention.Furthermore,the females with a smaller body length survived better than the larger females,indicating that the lesser food requirements for smaller body sizes may confer advantages during the winter when food availability was reduced.In addition,in agreement with the finding in many short-lived birds that survival rate increases with the increase of age,older(≥2-year-old)female Silver-throated Tits had higher overwinter survival than 1-year-old females.However,we did not find any correlation of morphological traits and age with survival in male Silver-throated Tits.These results illustrate differential selective effects of winter weather on female and male Silver-throated Tits and contribute to the knowledge of sex-specific selection on the phenotype of natural populations.

Overwintering covered with soil or avoiding burial of wine grapes under cold stress:Chinese wine industry’s past and future,challenges and opportunities

In northwest China,where winter is extremely cold and the grapevine is vulnerable to freezing damage,the application of soil covering has promoted the vigorous development of the local grape and wine industries.However,in recent years,the negative effects of burying soil for cold protection on the environment have gradually emerged.In some viticultural regions,the phenomenon of"summer forest,winter desert"has appeared.Therefore,it is urgent for the Chinese grape industry to find a better solution to overwinter safely and environmentally friendly.This review summarizes the advantages and disadvantages of widely used solutions to overwinter such as covering vines with soil,breeding of cold-resistant grapes,cold-resistant cultivation model,physical and chemical covering materials,and protected grape facilities were reviewed.Future overwintering measures were proposed which avoid burial and grape overwintering research directions.It also provides a theoretical foundation and technical support to improve grape yield and quality in northwest China.

Long-Term Effect of Photoperiod, Temperature and Feeding Regimes on the Respiration Rates of Antarctic Krill (<i>Euphausia superba</i>)

Antarctic krill is thought to undergo an annual cycle of biological processes to cope with seasonal changes in their environment. The question of whether, and to what degree, seasonal environmental parameters such as photoperiod, food availability and temperature govern metabolism in krill is not clear. In this long-term laboratory study, respiration rates were determined in krill incubated under simulated natural light cycle or total darkness, subjected to fed or starved conditions and on krill kept at different temperatures (-1°C, 1°C and 3°C). There was a strong and significant increasing trend of respiration rates with month in all experimental treatments. In August (late winter), the mean respiration rates ranged between 0.22 - 0.35 μL O2 mg.DW-1.hr-1 for krill in both simulated seasonal light and complete darkness, and 0.25 - 0.26 μL O2 mg.DW-1.hr-1 for both fed and starved krill. Mean maximal respiration rates were recorded in October and December for all light and feeding treatments (0.46 - 0.56 μL O2 mg.DW-1.hr-1). Mean respiration rates for krill in the temperature treatments ranged between 0.24 - 0.30 μL O2 mg.DW-1.hr-1 in September reaching mean maximal rates in November and February (0.60 - 0.71 μL O2 mg.DW-1.hr-1). The covariate total length of krill was found to be non-significant and there was generally no significant interaction of experimental treatment with month and only for photoperiod comparison was the treatment main effect significant. The dark treatment gave higher respiration rates, and this needs careful interpretation. Results here suggest that, although light, food availability and temperature significantly affect metabolic rates,

The Comparison of Cold tolerance of Three Species of Evergreen Broad-leaved Woody Plants

[Objectives]This study aimed to select evergreen broad-leaved woody plants with higher ornamental value and stronger cold tolerance for introduction from the south to the north,and to apply them to urban greening,so as to enrich the plant community structure of the landscape in the northern region.[Methods]Three species of evergreen broad-leaved woody plants,i.e.,Ligustrum lucidum,Ilex cornuta and Eriobotrya japonica,were selected as the experimental materials.The morphological performances and the changes of the physiological indexes were observed and measured during the overwintering period in the open field in Beijing.The relationship between the indexes and the low temperature was also analyzed.The strength of cold tolerance of the three species was compared.[Results]The electrical conductivity,the contents of MDA and proline were negatively correlated with the corresponding low temperature.The contents of soluble sugar and soluble protein increased with the dropping temperature,but they had little response to the short-term temperature rise.[Conclusions]Combined with morphological and physiological indexes,it was found that the changes of the contents of proline and soluble sugar among the physiological indexes were closely related to the cold tolerances of the three tree species of broad-leaved woody plants.The cold tolerance of I.cornuta was the strongest,E.japonica was the second,and that of L.lucidum was the worst.

Effects of Snow Cover on Alfalfa Overw intering and Turning Green

In order to investigate the effect of snow cover on alfalfa overwintering and turning green,6 different alfalfa varieties( including Longmu806,Gongnong No. 1,Aohan,Wega 7F,WL319 HQ,Caoyuan No. 3) were used as plant materials. There were 4 treatments in this study include snow-cover of 0,30%,70% and natural snow-cover( used as control). Nutrient content and antioxidant enzyme activity of root were measured before and after overwintering period. The rate of plant returning green and growth rate after greening were also measured after turning green. The result showed that the snow cover was the guarantee of alfalfa safely overwintering and turning green. The 54. 5-77. 9 cm snowfall was the optimum thickness of snow for safe overwintering. Alfalfa improved the overwintering ability by enhancing the root nutrients and antioxidant enzyme activity,and it was affected by snow cover. In addition total nitrogen and soluble sugar increased by 61% and 60% respectively,soluble protein reduced by8%,SOD and CAT reduced by 20% and 9% respectively than that before the overwintering under 70% of natural snow-cover. There were differences between overwintering ability of 6 different alfalfa varieties,in which Caoyuan No. 3 has more grass production and Wega 7F has stronger overwintering ability.

Physiological changes of leaves in response to cold in Phyllostachys propinqua

There are no previous records about planting bamboo in Changli, Hebei Province, north China. Since they were introduced in 2004, the propinquity bamboo （Phyllostachys propinqua McClure） has demonstrated good adaptability to the cold climate in Changli. The overwintering status of the bamboo and some of its physiological changes after the winter have been studied to ascer- tain the adaptability of the bamboo to the cold weather in Changli and to establish a firm basis for growing the plants in larger areas in northern China. The bamboo lived through the winter without any protection. The leaves of windward bamboos growing at various intervals have been studied for their viability and health after the winter. The changes in some physiological indices of the leaves were measured in the following spring. Results showed that the bamboo is partly green even at a temperature as low as -22.3℃ in Changli. During the winter, some leaves died and some partly died. Leaves are light in color and turn gradually to a dark green when the temperature increases in the following spring. As new leaves develop, the contents of chlorophyll and water and the ratio of fi＇ee and bound water in the old leaves increase as does transpiration. At the same time the contents of free amino acid, proline, soluble sugar, malondialdehede （MDA）, permeability of the membrane, superoxide dismutase （SOD） and peroxidase （POD） activities de- crease. The direction of these physiological indices changes when the new leaves begin to sprout. The old leaves reduce their rate of photosynthesis, their blade functions decline gradually and the leaves fall off towards the middle of June. The cold wind affects the survival of bamboo leaves in winter, but has little effect on new leaves growing at the start of the following year. The results indicate that the propinquity bamboo can survive the winter in Changli quite well.

Cold hardiness of the invasive fall armyworm,Spodoptera frugiperda in China

Fall armyworm,Spodoptera frugiperda(J.E.Smith,1797),a crop pest native to tropical and subtropical regions of America,has invaded and spread into most regions in China,posing a severe threat to China’s agriculture.The cold hardiness directly determines its geographic distribution through adapting to winter temperatures of different regions.Here,we measured supercooling points and lethal time(LT)at low temperatures of S.frugiperda.The supercooling points for developmental stages in increasing order were:adults(-15.05℃)<pupae(-13.25℃)<prepupae(-10.50℃)<larvae(-9.03℃).Among eggs and 1st to 4th in star larvae,the 99%lethal time(LT_(99))was the highest for 4th in star larvae,with 99%of larvae dying after 18.59 d at 2℃,58.72 d at 7℃,and 66.28 d at 13℃.LT_(99) was the lowest for eggs with LTgg of 5.33 d at 2℃,9.28 d at 7℃,and 12.97 d at 13℃.This study provides mn understanding of overwintering regions of S.frugiperda in China which will be helpful for population forecasting and management.

RECENT ADVANCES IN THE PHYSIOLOGY OF FOREST INSECTS IN CHINA

In China the research in the phusiology of forest in inseets began in the 1970s,and in the 1980s a great deal of research works was done in this field,a lot of which were concen-trated on the isolation,identification and synthesis of sex pheromones on the injurious forest in-seets with in Lepidopteron and Coleopteron.In the field of tree resistance physiology,some ad-vanees were achieved in the resislance mechanism of poplar to Longicorn beetles and prominents.The research of the resistance of plne to Matsucoccusmalsumurae Kuwana is now also going on.In addition,the seductive function of plant sex seducements to the Longicorn bee-tle and its digestion physiology are also being studied.Many reports on the analysis of proteins,isoenzymes and amino acids applied to classification of Longicorn beetles,Pine moths and Aphids have been published.A relatively deep insight was gained in the physiological characters of overwintering larvae of Coleophoradahuriea Flkv.in the deep cold region of Hellongjiang

Effects of sowing time on bolting and returning green in welsh onion

Qiyechangbai and Hadacongl were used to study the relationship of the leaf age of overwinter to bolting and, returning green by the difference of sowing time. The results showed that the earlier the seeds were sown, the older leaf age of overwinter was, the higher the rates of returning green and bolting rate were, the earlier the bolting time was. The leaf age of overwinter of Qiyechangbai sown August 31 to September 14 was 2.1-3.1 leaves and the rate of returning green was 86.5%-92.1%, while the leaf age of overwinter of Hadacongl sown September 7 to September 14 was 2.3-2.7 leaves and the rate of returning green was 88.5%-93.8%, both varieties didn＇t bolt. In addition, in the same sowing time, the bolting rate of Hadacong I was higher than that of Qiyechangbai slightly.