The effect of low temperature adversity on male flowers and pollen inLarix olgensis

The electric conductivity of pollen life-force and male flowers ofLarix olgemis on condition of low temperature adversity has been respectively measured by means of fluorescent dying method and conductivity method in 1992 and 1994. The results indicate that: (1) If the same clonal pollen is treated at equal time at different low temperatures, there are significant differences in pollen life-force, the pollen life-force is the largest between O°C and -3°C, in higher or lower temperature range, the pollen life-force will decrease. The measurement of electric conductivity of male flowers proves that the low temperature of below -3°C is the main reason that the cell membrane is damaged and the pollen life-force decreases. (2) The same clonal pollen life-force at the same low temperature will gradually decrease with the increasing of frozen time. Its main reason is that suffocation and losing body fluid result in the damage of cell membrane, the measurement of electric conductivity of male flowers can prove that. (3) If pollen is treated with the same low temperature, the humidity will be the main factor of affecting pollen life-force. (4) There are significant differences inLarix olgensis’s resistance against low temperature in its different growth stage, the male flower’s resistance of near pollen spreading period is low. (5) The resistance is different within clones. (6) The resistance against low temperature ofLarix can be increased by means of chemical treatment.     

Vitality and storage condition of Syringa pollen

The fresh pollen vitality,the effect of different storage conditions on the pollen vitality,and the difference of vitality among the species of seven species of Syringa were determined in Shenyang,China.The results indicated that the pollen vitality (81.5%) of Syringa villosa was the highest among the seven tested species,followed by S.microphylla and S.meyeri,and that of S.oblata var.affinis was the lowest.The low temperature was the best condition for storage of pollen of Syringa,and the most proper temperature for the storage was 0-2℃.The storability of S.microphylla was the best of all,and it could be stored over 60 days at the temperature of 0-2℃,next was S.villosa and S.meyeri.     

Comparative study on drought resistance ofLarix olgensis Henry andPinus sylvestris var.mongolica (I)

Water potential (ϕ w) and net photosynthetic rate (Pn) ofLarix olgensis andPinus. sylvestris var.mongolica decreased with the decrease of soil water content. ϕ w and Pn ofL. olgensis changed hardly during the first 9 days after stopping watering, then decreased sharply at the 10th day Pn ofP. sylvestris varmongolica decreased slightly during the first 8 days, then decreased sharply at the 9th day. Their respiration rate, chlorophyll content and their a/b ratio changed hardly. The following 3 conclusions were obtained and discussed exhaustively. (1) ϕ w can be used to direct watering as a sensitive index of judging whetherL. olgensis andP. sylvestris var.mongolica lacking water. (2) The decrease of Pn ofL. olgensis andP. sylvestris var.mongolica when drought had nothing to do with chlorophyll. (3)P. sylvestris var.mongolica had morphological drought resistance, while Lolgensis had physiological drought resistance, and their drought resistance was discussed comparatively first time.     

A study on the geographic variation and selection of the best provenance ofLarix olgensis

On the basis of the results from the geographic provenance test of nine years oldlarix olgensis in Liangshui Natural Reserve of our university, a study on the geographic varition and the primary selection of the best provenance ofLarix olgensis was carried out. The main results are as follows: I.The different provenances ofLarix olgensis have rich and wide genetic variation, and exist a linear correlation with latitude and longitude in collection area. General trends are enumerated below: Provenances at lower latitude and more west longitude have lighter thousand seed weight, short growth period, higher increment, wide branches, rich leaves and crown as well as worst adaptabillity. It is a dual-way variation along with two directions of latitude and longitude, and also embodies a change gradually in climate condition from south to north. The temperatures in seed production site, especially the mean temperature in January and ≥10 °C accumulated temperature, are important factors that produce geographic variation forlarix olgensis. 2. The variation of different provenances in periodic biological phenomena and growth rhythm trends are that: 1 both of the provenances from Changbai Mt. (III) and Dashitou(IV) at low latitude belong to the centralized growth type, and have shout growth period, the difference between these two provenances is that the provenance from Changbai Mt. grows well in all time, Dashitou provennce is well only in later period; 2 the provenance from Baidao Mt. (II) at middle latitude belongs to even growth type and has longer grpwth period, this provenance has higher increment in early and later periods relatively; 3 Xiaobeihu provenance at high latitude is a growth type among II. III and IV provenances and has a general growth period, the provenance grows better in middle time and worse in later time. 3. The best provenance in Liangshui Natural Reserve and its meighbourhood is Dashitou Procenance, which growth in height, diameter and volume has exceeded 16. 28%, 46. 27%, 30. 58%, 78. 20, 82. 00% as well as 392. 00% by comparison with the mean value of the contrast and the worst provenance respectively, The result from the height growth of three, five, seven and nine years oldLarix olgensis by using the method of order correlation analysis demonstrates that it is possible to make early selection of the provenance. Meanwhile, data from juvenile and mature oflarix olgensis plantation also prove the reliability of the early selection. 4. The provenance heritabilities of nine years oldlarix olgensis in Liangshui Natural Reserve are follows: The heritability of the height growth (h²) is 0.79; The heritability of the diameter breast height (h²) is 0.791; The geretic gain is 24.5% and 40.36% respectively.     

Study on photosynthetic characteristics ofLarix olgensis Henry at Erlongshan Forest Farm

Net photosynthetic rate (Pn) and respiration rate (R) of different directions and levels of crownof Larix olgensis Henry, growing at Erlongshan Forest Farm, were different. Pn of 14-year-oldL. olgensis was the biggest at the west of crown, and the lowest at the east of crown. Diurnal process of Pn of the south of crown showed monopeak curve pattern. Diurnal processes of Pn and R of 7-year-old and 16-year-oldL. olgensis showed bipeak curve pattern. Seasonal process of Pn ofL. ol-gensis showed monopeak curve pattern. Light compensation and saturation points ofL. olgensis were 18 and 1080 μ molm⁻² s⁻¹ respectively. Chlorophyll content of different directions and levels of crown ofL. olgensis were different. Chlorophyll content increased with the passage of time (May 22 – September 13), and reached its biggest content at August, then decreased. Seasonal process of chlorophyll content, like that of Pn, showed monopeak curve pattern. Chlorophyll content related to Pn positively.     

Study on physiological characteristics ofLarix olgensis andFraxinus manshurica under controlled conditions

The net photosythetical rate, respiration rate, light compensation point and light saturation point ofLarix olgensis andFraxinus manshurica were measured by Model-865 Co² Infrared Analyzer under controlled conditions (in coviron phytotron). For net photosythetical rate ofLarix ogensis andFraxinus manshurica, the optimum air temperature was 25, 28 °C respectively, the optimum soil water potantial was −20, −10 kPa repectively, the optimum soil water content was 20.31 %, 23.42% respectively, and the optimum air humidity was 90%. The optimum soil water potantial of respiration rate was −30 kPa. The light compensation point for the two species was 3.36, 4.8 μ mol / m²s respectively and light saturation was 804, 880 μ mol / m²s. The project supported by National Natural Science Foundation of China     

Geographic variation pattern ofLarix olgensis

On the basis of the data of provenance test for 10 years in the total natural range ofLarix olgensis from 10 seeds collection sites, the geographic variation patterns have been made by means of canonical correlation analysis: (1) The basic variation patterns of growth characters is in vertical gradual change along the elevation gradient as principal, and gradual change along the latitude as supplement. (2) The Xiaobehu provenance with low elevation and low equivalent latitude is the good gene resource center ofL. olgensis. It has the genetic characters of rapid growth, high stability and fine timber quality. (3) The synthetical interaction between water and heat factors is the major factor to produce the variation ofL. olgensis and the temperature is the principal one. (4) Among the genetic variations of geographic population characters, the variation of growth is the most obvious one, and it could be taken as the main character for provenance division. (5) By allocating the seeds from the low equivalent latitude region to the northern suitable afforestation areas, the greater genetic gain could be obtained. (Responsible Editor: Chai Ruihai)     

低温对长白落叶松花粉生命力的影响

长白落叶松花期常常遇低温和霜冻，使雌雄花受冻，从而影响种子结实量。文章研究了不同低温对长白落叶松花粉生命力的影响，得出以下结论：-3～0℃是花粉的最佳保存温度；在相同低温条件下，随着处理时间延长，花粉生命力降低；撒粉前不同时期用低温处理对花粉生命力影响显著，愈靠近撒粉期的低温处理危害愈大；不同无性系在温度及储藏时间相同条件下，花粉的抗性不同。     

Study on biological and ecological characteristics ofIps subelongatus Motsch

Ips subelongatus Motschulsky were raised indoors and in the field using fresh baits for study of biological and ecological characteristics during 1992–1994. The life cycle of the pest in Lishu County, Jilin Province was described. The study results indicated that temperature was a main factor affecting the development ofIps subelongatus. The initial temperature for development of egg, larva, pupa and adult was 6.1, 8.0, 10.3 and 9.8°C, respectively. To complete one-generation needs, respectively, 48 d at temperature of 18°C, 39 d at 20°C and 33 d at 22°C. The pest has different number of generations in different area as a result of temperature change. In Jilin Province, it generally has three generations, except that some individuals have 2 generations. The nature enemies for this pest areThanasinus substriatus, Tomimicobia seitneri Ruschk,Coeliodes sp. etc. Foundation item: This paper is part of key subject of the Ministry of Forestry (formerly)—The Systematic Control Technique ofIps subelongatus Motschulsky. Biography: G{upao} Chang-qi (1952-), male, research fellow in Jilin Forestry Academy. Responsibe editor: Chai Ruihai     

温度对大叶桃花心木(Swietenia macrophylla King)幼苗叶片的光合影响

本文研究了大叶桃花心木（Swietenia macrophylla King）一年生幼苗在经过夜温处理后的光响应曲线和在饱和光强下的CO2反应曲线.结果表明:在大气CO2浓度下,叶片的最佳光合作用温度在25-31℃之间,而在饱和CO2浓度下为31-35℃.在25℃以下光合速率开始降低,主要是由于羧化效率的降低,而当温度超过31℃时,光合速率下降,是因为羧化效率的降低和呼吸速率的增加.CO2浓度对光合的促进作用在低温下受到抑制,这意味着未来在CO2浓度增高的情况下,高浓度的CO2对热带常绿植物光合的促进在冬天低温情况下表现不十分明显.图4参23.     

Haploid breeding ofpopulus

After 14 year’s growth observation on the plant growth, it was found that obvious segregation appeared among the haploid pollen plants obtained from anther culture ofPopulus Xiaohei T.S. Hwany ex C. Wang et Tung in vitro. By vegetative propagation, 19 clones were selected and field contrast test was carried out. Statistical analysis result showed a significant difference in volume production. They are superior clones which could be selected from among the pollen plants for utilization. A haploid breeding procedure is suggested in the paper. This study was supported by the National Natural Science Foundation of China     

The effect of alternating temperature on the rest break process of male flowers of Cryptomeria japonica D. Don

In order to develop a model for predicting the period of male flower anthesis in Cryptomeria japonica, it is requisite to clarify the rest break process in male flowers. In this study, the effect of alternating temperatures in a daily cycle on rest break was investigated using twigs bearing male flowers from three clones of C. japonica. Four temperature treatments with the same daily mean of 8°C were applied to sample twigs over a period of 35 days: (1) 8°C constant (TR-A); (2) 7°–10°C alternating (TR-B); (3) 5.5°–13°C alternating (TR-C); and (4) 4°–16°C alternating (TR-D). After treatment, the sample twigs were forced to bloom at a constant temperature of 16°C, and the cumulative effective temperatures (CETs) required for anthesis were compared. While the CETs for anthesis were the same for TR-A and TR-B, that for TR-C was significantly higher. After TR-D, almost no male flower bloomed, indicating that this treatment was ineffective in breaking rest. When considering these results on an hour basis, it was a reasonable interpretation that 13°C had no effect on breaking rest while the temperatures below 10°C were all equally effective. On the other hand, temperatures of 16°C or above were considered to have an antagonizing effect that cancels the effects of chilling temperatures below 10°C. These results suggest that the effects of high temperatures during the daytime in chilling periods should be properly incorporated into a model of the process by which rest of male flowers is broken.     

基于MaxEnt生态软件划分澳洲坚果的潜在地理适生区

[目的]对澳洲坚果在中国的潜在分布区进行预测,并对其适生区进行分析和划分。[方法]通过收集澳洲坚果的地理信息数据,利用最大熵模型(MaxEnt)与地理信息系统(ArcGIS),综合相关19项气候因子,预测划定澳洲坚果在世界以及我国的潜在地理分布区。[结果]该物种生长区域狭窄,对环境要求苛刻。世界范围内,澳洲坚果的较适宜生长区在澳洲东部、南美洲东南部和马达加斯加岛东部以及亚洲地区23°26'~30°N,73°~122°E范围内。在我国,澳洲坚果适宜分布区主要集中在西藏、台湾、广西、广东和云南等地,其高适宜区面积依次为西藏(15 359km~2),台湾(14 054 km~2),广西(7 372 km~2),广东(6 147 km~2)和云南(3 776 km~2)。刀切法(Jackknife)分析显示,澳洲坚果分布主要受到极端最高温、年均气温变化范围、最干月降雨量、温度季节性变化和等温性等气象因子的影响。[结论]本研究用MaxEnt模拟澳洲坚果的潜在地理分布有一定的准确性,划分出了澳洲坚果基本的地理分布格局和潜在分布区域,并阐明了主导其地理分布的生物气候因子,为澳洲坚果尤其是在我国的引种和推广应用提供了参考。     

Study on biological characteristics ofHendersornia acicola

The morphological and cultural characteristics ofHendersonia acicola Munch & Tub., isolated from the needles ofPinus sylvestris var.mongolica Litvin, were described. The fungi was cultured on three kinds of media and the speed of mycelial growth and the required time to produce conidia were different. On the medium of needle decoction agar, the fungi grew fast and produced conidia after 5 days culturing. On PDA came second and it needed 7 days to produce conidia. On the medium of maize flour agar, it grew slowly and produces conidia after 27 days incubating. The fungi cannot produce conidia under darkness on all three kinds of media. The conidia can germinate at 8°C–28°C. The optimum conditions for conidia to germinate are 25°C, RH 100% and pH 4 and under these conditions it only takes four hours for conidia to germinate. The conidia germination is not affected by light     

A study on Xingkai Lake pine gall rust

The Xingkai Lake pine (Pinus takahasii Nakai) gall rust caused byCronartium quercuum(Berk.) Miyabc: Shirai is a serious stem rust in the northeast region of China. The alternate host is oak (Quercus mongolica Fisch). Germination of both acciospores and urediospores was optimal at 12°C and occurred over a range of temperatures, from 4°C to 32°C. Teliospores germinated optimally at 16–18°C and over a range of 8–28°C. All spores germinated best under natural light and dark conditions. Direct light inhibited germination even when followed by darkness. The incubation periods of urediospores and teliospores in inoculation experiments were 6–16 days and 3–33 days respectively. Anatomical studies ofCronartium quercuum galls showed that rust hyphae freely ramify through the intercellular spaces within parenchymatous tissues of the cortex, phloem, cambium and xylem. Hyphae are perennial; large haustoria arc cylindrical with rounded or blunt ends. Among the 12 fungicides tested for control of the rust, pine-tar, pine-tar: diesel oil (1:1, 1:3, 1:5), 75% Bravo emulsion and 70% Mancozeb emulsion applied to the galls produced satisfactory results.     

Untersuchungen zur Widerstandsfähigkeit von Khaprakäfern (Trogoderma granarium Everts) gegen Methylbromid bei niedriger Temperatur in Abhängigkeit von Konzentration,Nachbehandlungsart und Entwicklungsstadium

Investigations about tolerance of Khapra Beetle (Trogoderma granarium Everts) to methyl bromide at low temperature in relation to concentration, type of post-treatment and stage of development The influence of variou methyl bromide concentrations (5–100 g/m³ was investigated at 5 °C on the tolerance ofTrogoderma-larvae in relation to two post-treatment methods. Experimental results show that there are no significant differences betwenn the mean of the ct-products of the higher concentrations (18–100 g/m³ and of the lower concentrations (5–12 g/m³ producing 90 and 99.9 per cent mortality, if the larvae are kept for another 10 days at this fumigation temperature before they are held at 28 °C until final control.      

Concentrations and seasonal dynamics of dissolved organic carbon in forest floors of two plantations （Castanopsis kawakamii and Cunninghamia lanceolata） in subtropical China

The concentrations and seasonal dynamics of DOC in forest floors of monoculture plantations ofCastanopsis kawakamii and Chinese fir (Cunninghamia lanceolata) were assessed in Sanming, Fujian, China (26°11′30″N, 117°26′00″E). Forest floor samples were taken in January, April, July and October in 2002 and divided into undecomposed material (horizon Oi), partially decomposed organic material (horizon Oe), and fully decomposed organic material (horizon Oa). Upon collection, DOC concentrations of samples were analyzed by a High Temperature TOC. The results showed that the annual average DOC concentration of Chinese fir (1341.7 mg·kg⁻¹) in the forest floor was higher than that ofCastanopsis kawakamii (1178.9 mg·kg⁻¹). Difference in DOC concentrations was observed among three horizons of the forest floor. DOC concentration of forest floor in the two forests was the highest in horizon Oe. Seasonal trends of DOC concentrations in different horizons of forest floors were similar and the maximal value occurred in autumn (or winter). The concentration and temporal change of DOC in studied forests were probably related to the variation in moisture, temperature, biological activity and quantity of organic matter in the forest floor. Foundation item: This study was supported by the Teaching and Research Award program for MOE P.R.C. (TRAPOYT) Biography: ZHANG Jiang-shan (1946-), male, Researcher in Fujian Normal University, Fuzhou 350007, P.R. China. Responsible editor: Zhu Hong     

STUDY ON KOREAN PINE NEEDLE RUST

TheneedlerustofKoreanpine(tbceo3Poriam5bus=vureaeThUm)isacom-lnondiseaseinYichunforestregion.ltmainl}:hamstheneedlesofyoungtrCeswhichareundertheageoffifteen,affectsthegrowthofthemtosomedegree.Thepathogenicfungushadbeenreportedl"'].Inordertoidentifythepathogenand1ifehistoryoftheneedlerustsofKoreanpineandfindouttheoccurringlatvandeffecti\'econtfolmeasure,asystCmaticsurveyx`ascarriedoninYichunforestduringl992-'l994.DISTRIBUTlONANDHARMAccordingtothesurveyofinsectPestsandplantdiscasesin…     

Temperature-dependent functional response of two aphid parasitoids, Aphidius colemani and Aphidius matricariae (Hymenoptera: Aphidiidae), on the cotton aphid

The functional response of two aphid parasitoids, Aphidius colemani Viereck and Aphidius matricariae (Haliday) (Hymenoptera: Aphidiidae), on the cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae), was examined. Five constant temperatures (10, 15, 20, 25, and 30°C) and six host densities (2, 4, 8, 16, 32, and 64) were used during a 24-h period. At each temperature, 2–64 third-instar nymphs of A. gossypii were exposed to individual wasp mating pairs. A type II functional response model for both parasitoid wasps was fit separately for each temperature. The results showed that instantaneous attack rate (a) in A. colemani increased linearly as the temperature increases from 10 to 30°C, but in A. matricariae, (a) increased almost linearly with temperature to reach a maximum at 25°C, and then decreased at 30°C, displaying an asymmetrical dome-shaped pattern. The highest instantaneous attack rate for A. colemani and A. matricariae were calculated 0.940 ± 0.144 day⁻¹ at 30°C and 0.687 ± 0.157 day⁻¹ at 25°C, respectively. Handling time (T _h) for A. colemani was inversely proportional to temperature and ranged from 0.093 ± 0.026 day at 10°C to 0.032 ± 0.004 day at 30°C, but in A. matricariae, (T _h) was between 0.078 ± 0.015 day at 10°C and 0.036 ± 0.014 day at 20°C. A. colemani achieved higher parasitism rate than A. matricariae at higher temperatures. This observation suggests that A. colemani maybe more effective for biological control of the cotton aphid during warmer periods.     

Seasonal change in the temperature coefficientQ 10 for respiration of field-grown hinoki cypress (Chamaecyparis obtusa) trees

The effect of temperature upon nighttime respiration was examined on four different sized sample trees in a 17-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) stand over two years. Seasonal changes inQ ₁₀ values and their responses to mean temperature were investigated. On the basis of the monthly relationships between nighttime respiration (r) and temperature inside a chamber (θ),r=r ₀exp (kθ), theQ ₁₀ value (=exp(10k)) was calculated. TheQ ₁₀ values were high (Q ₁₀≥3.0) in winter when mean air temperature was low, and gradually decreased toward summer (Q ₁₀≤1.5) through spring with increasing temperature. TheQ ₁₀ values were negatively correlated with mean air temperature. The response ofQ ₁₀ values to mean air temperature was described by a single equation, regardless of tree size. This result, which might be characteristic of this species, shows that respiration ofC. obtusa trees is promoted by slight increases of air temperature in winter season. On the other hand, temperature sensitivity of total respiration reduced during growing season when ambient temperature was high. These chaning temperature sensitivity according to seasons may depend on the seasonal change of the ratio of growth respiration to total respiration. It is concluded that changes in temperature due to changing seasons not only change respiration rate, but also change the response of respiration rate to temperature by shiftingQ ₁₀ values.