杂交榛子一年生枝条长度与其花芽数量的相关性研究

榛树的花芽为雌花混合芽，1年生枝的基部到顶端均有分布。雌花混合芽同叶芽外观极其相似，开花前肉眼无从分辨。本试验通过雌花盛开期对榛树1年生枝条长度及其花芽数量调查，分析两者间的相关性，为榛树的栽培管理提供理论依据。     

Root shoot interactions in passionfruit (Passiflora sp.) under the influence of changing root volumes and soil temperatures

Summary

Passionfruit are grown in the tropics and subtropics where mean monthly soil temperatures at 15 cm range from about 10° to 30°C. The choice of rootstock can also influence production with most industries exploiting either the purple (Passiflora edulis f. edulis) or golden passionfruit (P. edulis tflavicarpa). We examined the relationship between shoot and root growth in purple x golden hybrid E-23 grafted onto golden passionfruit seedlings. Growth was manipulated by varying the volume of the soil available to the roots or temperature of the root zone. Shoot and root growth increased as root zone volume increased from 0.3, 1.4, 4, 12 to 24 1. Shoot weight (W_s) was correlated with root weight (W_R):W_S = 12.697 + 5.272 W_R + 0.195 W_R² (r² = 91%, P<0.001), with the plants allocating a smaller proportion of dry matter to the roots as root weight increased. Differences in shoot growth with pot volume were not due to changes in water or nutrient status. In the temperature experiment, the two critical root zone temperatures at 90% of maximum growth were about 20° and 35° C for vine extension, leaf area, node and leaf production, and 20° and 30°C for flower production. Leaf and stem dry weight were optimal between about 18° and 34°C, while maximum root growth occurred at 38°C. There was a weak relationship between shoot (W_s) and root dry weight (W_R): W_s = ?19.346 + 24.500 W_R ?1.046 W_R² (r² = 53%, .P<0.001). Apparently, variations in shoot growth at different soil temperatures cannot be explained solely by differences in root growth. Reduced growth at 10°C was associated with lower chlorophyll concentration, stomatal conductance and net CO₂ assimilation, but not lower leaf water potential. The concentration of most nutrients were lower at 10°C than at higher temperatures, but none was outside the range which would be expected to restrict growth. There appears to be a co-ordination of shoot and root growth as the soil volume available for root growth increases, whereas root temperature affects the roots and tops differently. The results of the pot volume experiment demonstrate the importance of rootstock vigour in passionfruit breeding. Productivity would be affected in cool subtropical areas with soil <20°C and in tropical areas with soil >30°C.     

Variability of first flower to ground distance in olive seedlings and its relationship with the length of the juvenile period and the parent genotype

During development, most woody plants that develop from seeds undergo a juvenile phase before transitioning to adulthood. The first flowering indicates the end of the juvenile period and can be used as a marker to discriminate between phases. In this study we analyzed the distance of the first flower from the ground, measured along the trunk and supportive branches, in 385 olive seedlings coming from eight different crosses. We found that for tree canopy base heights of 1.5 and 1.0 m the average distance at which the first flower appeared was 2.41 or 2.07 m, respectively. Moreover, we observed for the first time that the first flower to ground distance was significantly correlated with the juvenile period length and the olive seedling parent genotype. In fact, a particular cultivar demonstrated a consistent influence on the location of the progeny first flower, irrespective of being used as female or male parent. This implies that the first flower to ground distance may not be constant within the olive species.     

Effects of shoot size,number of continuous-light cycles and solar radiation on flower initiation in the carnation

Carnation plants (Dianthus cary ophyllus L.) cultivar ‘White Sim’, were grown in containers in a glasshouse under short (8 h) days. When the primary shoots had 4, 8 or 12 pairs of visible leaves, the plants were moved to a continuous-light area, lit by tungsten lamps for 5, 10, 15 or 30 days, and then returned to short days. This was repeated with several sets of plants at different times of year to obtain a range of radiation flux densities.The number of continuous-light cycles required to initiate a given proportion of shoots was dependent upon the radiation integral, a generalised linear model gave quantitative relationships between the proportion of responding shoots, the number of cycles of continuous light (CL) and the radiation integral. For shoots with 4 visible leaf pairs the model

$\text{keta;=μ+∝X}{}_1\text{+βX}{}_2$

accounted for 83% of the deviance, where η is the linear predictor, μ, α and β are parameters, X₁ = log_e (number of CLs + 1) and X₂ = log_e mean radiation (calories cm^?2 day^?1). For shoots with 8 visible leaf-pairs, 76% of the deviance was removed.Under low radiation integrals, intra-plant competition resulted in only a small proportion of shoots on a plant initiating flowers; increasing the number of CL cycles only partially mitigated this effect. At low radiation integrals, shoots that failed to initiate flowers in CL were often delayed by this treatment and initiated flowers later than shoots in short days. Both the CL-requirement and the limiting effect of the radiation integral on the proportion of shoots that initiated flowers decreased as shoot size increased.It is concluded that competition for photosynthetic assimilates under low radiation conditions can severely limit flower initiation in the carnation.     

Influence of seed position within the fruit on seedling quality and in vitro shoot tip production of jackfruit

This study reports on the influence of seed position within the fruit and shoot development on the production of jackfruit in vitro. Seeds were extracted from the different sections in the fruit and shoot tips excised from the resultant seedlings. The tips were cultured in vitro on media supplemented with 6-benzylaminopurine (BAP) or thidiazuron (TDZ). The seeds from the middle and basal sections of the fruit were larger and produced larger seedlings than those from the top. Seeds from the basal position took 10 days to germinate and produced seedlings 11 cm tall with four or five leaves. Partially covered and fully open shoots from 6–8 week-old seedlings performed best. The highest frequency of shoot induction (100%) and multiple shoot production (7.31 ± 1.2) with a mean length of 3.6 ± 0.13 cm was observed on Murashige and Skoog (MS) media supplemented with 3.0 mg/L BAP. Driver and Kuniyuki (DKW), and MS media were equally effective in shoot multiplication. More than 80% of the rooted plants survived culture, indicating that this technology could be used to conserve wild germplasm.     

Factors affecting intraspecific variation in home range size of a large African herbivore

Factors affecting intraspecific variation in home range size have rarely been examined using modern statistical and remote sensing methods. This is especially true for animals in seasonal savanna environments in Africa, despite this biome??s importance for both conservation and development goals. We studied the impacts of spatial and temporal variability in environmental conditions, along with individual and social factors, on home range sizes in African buffalo (Syncerus caffer) in northeastern Namibia. Our data set spans 4?years, is derived from 32 satellite tracking collars, and contains over 35,000 GPS locations. We used the local convex hull method to estimate home range size from 31 buffalo captured at 6 sites. We used a variety of remotely sensed data to characterize potential anthropogenic and natural boundaries, as well as seasonal and temporal heterogeneity in environmental conditions. Using an information-theoretic, mixed effects approach, our analyses showed that home ranges varied over two orders of magnitude and are among the largest recorded for this species. Variables relating to vegetation and habitat boundaries were more important than abiotic environmental conditions and individual or social factors in explaining variation in home range size. The relative contributions of environmental, individual, social, and linear boundary variables to intraspecific home range size have rarely been examined and prior to this had not been assessed for any species in seasonal savannas of Africa. Understanding the factors that condition space-use patterns of wildlife in this area will lead to better-informed conservation and sustainable development decisions.     

The effect of soil temperature on lateral shoot formation and flower-bud formation in apple in the first year after budding

Under controlled environment conditions the influence of four soil temperatures (7°, 14°, 21°, and 28°C) on vegetative development and flower-bud formation of apple trees (cvs ‘Rode Boskoop’ and ‘Elstar’) were evaluated in the first year after budding. Relative air humidity was high, air temperature was 20°C. Broadly speaking, for both cultivars shoot growth clearly increased with increasing soil temperature. The effects on growth were mainly reflected in the number (not length) of the lateral shoots; the growth of the main shoot was little influenced by soil temperature. At 7°C the lateral shoots usually occurred higher along the main stem than at the higher temperatures. Flowering on the parent stem and on the lateral shoots was little affected by the soil temperatures tested. In general, flower-cluster quality was rather poor. If only clusters having more than four well-developed flowers are considered, flowering was favoured by higher soil temperatures; at 28°C, especially, cluster quality was much better than at the other soil temperatures. It is concluded that soil temperature is important in controlling the degree of lateral shoot-formation as well as the formation of well-developed flower clusters.     

Effect of maleic hydrazide on endogenous cytokinin contents in lateral buds,and its possible role in flower bud formation on the Japanese pear shoot

In order to elucidate the role of maleic hydrazide (MH, 1,2-dihydro-3,6-pyridazinedione; coline salt) in increasing flower bud formation on the Japanese pear, the effect of MH on cytokinin contents in the lateral buds of Japanese pear shoots were investigated. Foliar application of MH at 2600 mg l⁻¹ increased zeatin, zeatinriboside, and isopentenyladenine levels in lateral buds though isopentenyladenosine concentration decreased. Application of 2,3,5-triiodobenzoic acid (TIBA), an inhibitor of polar auxin transport, also increased the endogenous cytokinin levels in lateral buds. It is supposed that these increases of cytokinin in lateral buds may be involved in the increase of flower bud production on the Japanese pear shoot. The increases of cytokinin induced by these chemicals may be caused via the depletion of the auxin level and/or the activity in shoot tissues.     

The effect of time of seedling emergence and density on the marketable yield of spring cabbage

The individual weights of spring cabbage shoots at harvest are directly affected by the relative times of seedling emergence; a spread of only 5-10 d accounted for 46% of the weight variation at approximately 65 d after sowing. Also, competitive interactions between plants derived from early and late emerging seedlings were evident at densities lower than those used in commerce, and these competitive interactions intensified with increasing plant density. A model described by Benjamin (1988) was fitted to some of these data and then used to predict the yields of cabbages in various weight grades in an independent data set. There were some systematic deviations between predicted and observed yields but little evidence of this deviation for yields in the marketable grade of 150-250 g.     

甘蓝杂种致死遗传现象浅析及利用

杂种致死是一种生殖隔离类型,致死材料的鉴定及遗传分析不仅有助于了解杂种致死的遗传机制,还可以为致死基因的定位及克隆奠定基础。利用已知携带杂种致死基因的2份甘蓝材料35DH-26及Z-14,以及3份未知是否携带杂种致死基因的甘蓝材料YF(2)-2、103-34-7-6-337A、103-34-7-6-6-1121进行了有关杂交试验。试验结果表明,甘蓝杂种致死现象由细胞核基因控制,与细胞质基因无关;甘蓝杂种致死性状符合由2个显性互补基因控制的理论,2份材料35DH-26、YF(2)-2具有遗传等效性,而3份材料Z-14、103-34-7-6-337A、103-34-7-6-6-1121具有遗传等效性;在出现致死及半致死组合(35DH-26×Z-14)的基础上,对组合有半致死分离现象的父本材料继续进行系统分离、编号,并继续配对进行致死测配,最终从半致死现象的父本中筛选出一些单株,用这些单株配成组合(35DH-26×Z-14)后,植株性状正常。     

Analysis of regional variation of height growth and slenderness in populations of six urban tree species using a quantile regression approach

Inventory data of six urban tree species from seven cities across Germany were used to model regional variation of height growth, allometric scaling, and slenderness over a wide range of size and age using a quantile regression approach. Variation within and between species and cities was large. Height did not reach an asymptote but declined at higher ages, presumably because of reduction cuts. Allometric scaling and slenderness varied with wind climate, modulus of elasticity, and coefficient of drag. Our data do not support the use of a threshold value of slenderness in tree risk assessment.     

Genetic divergence in seedling trees of Persian walnut (Juglans regia L.) for various metric nut and kernel characters in Himachal Pradesh

The nature and magnitude of genetic divergence was assessed using non-hierarchical Euclidean cluster analysis in 229 seedling trees of Persian walnut growing naturally in four districts of Himachal Pradesh for 15 nut and kernel characters. Minimum and maximum values of coefficients of variability were recorded for nut width and kernel weight, respectively. All genotypes were grouped into 16 different clusters. The clustering pattern of walnut genotypes belonging to the same location revealed their distribution in more than one cluster showing non-parallelism between geographic and genetic diversity. Genotypes of clusters 5 and 8 were highly diverse from each other. Mean nut weight and kernel weight were highest in clusters 8 and 14, respectively. The highest mean kernel percentage and minimum shell thickness were observed in cluster 13. The highest mean value for fat was recorded in cluster 9 whereas cluster 3 had the maximum value of protein.     

Effects of auxin application on fruit formation in tomato growing under stress temperatures in the field

Summary

Tomato (Lycopersicon esculentum L. Mill) cultivars Early Urbana and Red Clode were grown in the field at adverse temperatures (stress regimes) until they set fruit in two growing seasons (Autumn and Spring) during 1999 and 2000 in Ahwaz (Southern Iran). To test the effectiveness of auxins in enhancing fruit set, racemes of tomato were sprayed during early fruit set with 25, 50 and 100 mg l^–1 4-chlorophenoxy acetic acid (4-CPA) and indole-3-butyric acid (IBA) followed by two additional applications at three intervals. The control plants were treated with deionized water. At harvest, racemes from autumn and spring plantings that were treated with 4-CPA had more large fruits than the control racemes. In both growing seasons, neither cultivar showed a significant difference in fruit set in plants treated with IBA, compared with controls. The ratio of fruit/flower in all racemes treated with 4-CPA increased significantly compared with the other treatments. However, auxin treatments did not significantly affect the number of flowers per raceme. Plants treated with 4-CPA produced the highest yield of marketable fruit. The greatest increase in total yield and parthenocarpic fruit occurred with 4-CPA treatments. Also, there was little difference between concentrations of 4-CPA on fruit set in both cultivars. It may be concluded that the response of fruit setting in tomato to either low or high temperatures regimes was auxin dependent and that 4-CPA was more effective than IBA.     

2008年柑桔受冻后的保花保果技术措施

2008年广西遭遇了历时20多天的50年来罕见的低温冻害袭击,给广西的柑桔造成了巨大损失和影响,为了尽快恢复生产,争取今年有一个较好的收成,把冻害损失减少到最低限度,笔者在对桂林、全州、兴安、资源和灌阳等县的柑桔受冻情况调查后提出了今年柑桔受冻后的保花保果技术措施.     

High temperatures and time to budbreak in low chill apricot ‘Palsteyn’. Towards a better understanding of chill and heat requirements fulfilment

The efficiency of different temperature cycles in inducing budburst of one-year-old shoots of the apricot cultivar ‘Palsteyn’ from dormancy was evaluated. Three replications of shoots were collected during two consecutive years from adult trees, following the accumulation of different amounts of chilling in the field. Thereafter, shoots were exposed to different temperature cycles in growth chambers, for 60 days. The temperature treatments included a continuous temperature of 5 °C; daily temperature cycles of 19/5 h at 5/15 °C, at 5/20 °C, and at 5/25 °C; and the same temperature cycles for the remainder of the 60-day period, after pretreatment at 5 °C for 30 or 45 days. After the temperature treatments, shoots were forced at 25 °C until budburst. The mean time to budburst (MTB) (in days) of lateral vegetative, terminal vegetative and reproductive buds was evaluated. The efficiency of the different treatments was greatly influenced by the date on which shoots were cut. High temperatures had a more positive effect on the reduction of MTB when chilling accumulation had occurred in the field instead of the growth chamber. After partial chilling accumulation in the field, high temperatures (25 °C) combined with low temperatures are more efficient than cycles of moderate temperatures (15 or 20 °C) to induce an earlier budburst. In view of these results, a parallel accumulation of both chilling and heat requirements after partial chilling accumulation is suggested. The application of these results could assist in the development of more accurate models for the prediction of the overcoming of dormancy and blooming.     

Genetic diversity in mainland and island populations of the endangered Pancratium maritimum L. (Amaryllidaceae) in Tunisia

Tunisian Pancratium maritimum L. populations are at present endangered and represented by scattered individuals as a result of coastal habitat destruction caused by urbanization and overharvesting for its significant ornamental interest. Nineteen populations growing in mainland and island habitats were sampled for allozyme diversity to assess their genetic diversity and structuration using seven isozymes revealed by starch gel electrophoresis. The species exhibited relatively high levels of genetic diversity (the mean A_p = 1.37, P = 37.4%, and H_e = 0.100), indicates a preferentially outcrossing mating system.     

基于SCoT与IRAP标记的金枣柿实生后代遗传变异分析及其生殖特性

【目的】金枣柿是浙江重要经济果树之一,其果实有无核与有核之分,在雄花未见的情况下,其后代遗传变异情况及生殖特性有待探讨。【方法】以金枣柿母本一的15个子代及母本二的16个子代为研究群体,以来自浙江不同地区的12个金枣柿单株及柿(Diospyros kaki)、君迁子(D.lotus)、山柿(D.japonica)为对照;采用SCo T和IRAP分子标记技术,分析金枣柿实生后代的遗传变异情况,并以此推测其种子来源。【结果】利用筛选出的21条SCoT引物及20条IRAP引物对供试材料基因组DNA的扩增结果表明,2种标记共扩增出473条清晰、可重复谱带,其中多态性谱带454条;2种标记的多态性比例分别为93.56%和97.50%。2个子代群体均产生了遗传分离。群体1通过SCo T和IRAP标记得到的DICE相似系数变异分别为0.637~1.000和0.927~1.000,群体2利用这2种标记得到的DICE相似系数变异分别为0.987~1.000和0.981~1.000。【结论】金枣柿的实生群体中均存在一定程度的遗传变异,其中群体1的DICE变异系数虽低于群体2,但其变异主要集中于个别单株,群体2单株的变异类型比群体1更丰富。金枣柿的种子主要由有性杂交产生,其花粉供体很可能为同种的雄花,不排除其具有兼性无融合生殖的能力。     

核桃枝条中总酚、黄酮类化合物含量研究

对祁县6个核桃品种1年生枝条韧皮部的总酚、黄酮类化合物含量进行了测定,并比较不同树龄间和不同品种间总酚、黄酮类化合物含量的差异。结果表明,核桃1年生枝条韧皮部总酚、黄酮类化合物含量在不同生长发育期存在显著差异,休眠期总酚、黄酮类化合物含量显著高于生长期;不同品种、不同树龄核桃1年生枝条韧皮部的总酚、黄酮类化合物含量差异显著;还对不同品种、不同树龄核桃1年生枝条韧皮部中总酚、黄酮类化合物含量与抗寒性的关系进行了分析。     

Effect of chilling on runner formation and flower initiation in the everbearing strawberry

Fresh and cold-stored plants of the everbearers ‘Rabunda’ and ‘Ostara’ were placed for 90 days, from the end of August, in glasshouses of the IVT phytotron at 14, 20 and 26°C and a daylength of 16 hours.In the fresh plants hardly any runners were formed at 14 and 20°C, but flowers were initiated, while at 26°C both runners were formed and flowers initiated. In the cold-stored plants, runners were formed first and thereafter flowers were initiated at all temperatures.It was concluded that (1) chilling induces runner formation, but can be replaced by high temperature, and (2) chilling delays flower initiation.