Distribution De Quelques Espèces De Cercopithecidae En Relation Avec Les Zones De Végétation De L’Afrique

The reproductive physiology of the impala was studied in the Kruger National Park. The data concerning the hypophysial hormones, the androgenic hormones and ovarian histology are discussed in relation to the behaviour of the animal.

It was found that the male animal shows the most profound behavioural changes which occur during the mating season. These changes are induced by an increase of interstitial cell-stimulating hormone which leads to an increase in androgenic hormone. The female shows relatively few behavioural changes during the mating season, the only change being at the time of oestrus.

On the basis of the data presented and information reported for domestic animals, it is postulated that the behaviour of the male impala plays an important role in determining the breeding season.     

庆元县受雨雪冰冻灾害毛竹林恢复重建技术探讨

庆元县位于浙江省西南边陲,东邻福建省寿宁县,南接福建省政和县,西挨福建省松溪县,北靠本省龙泉市、景宁县。竹产业经济在庆元举足轻重,已成为庆元县农民经济收入的主要来源,是庆元县国民经济的支柱产业。受2008年2月初雨雪冰冻灾害影响,庆元县毛竹林受灾严重,给竹农带来了巨大的损失。为使受灾竹林尽快恢复生产,减少因受灾而出现的返贫农户数,尽快恢复竹林的效益,庆元县多举措加快受灾竹林的恢复重建。     

临夏近30年春季低温冻害灾情分析

分析了1983～2012年临夏地区春季低温冻害的灾情。结果表明:4月份低温冻害发生的频率最高,5月份次之;低温冻害出现越迟,农业和林果业受灾越严重;近30年来,低温冻害的出现次数、致灾面积、造成的经济损失总体上呈上升趋势。提出了临夏春季低温冻害的防御措施。     

Pine processionary caterpillar Thaumetopoea pityocampa as a new threat for relict Mediterranean Scots pine forests under climatic warming

The wide distribution of Scots pine (Pinus sylvestris L.) in Europe includes two relict populations in southern Spain (Sierra Nevada and Sierra de Baza), belonging to the subspecies nevadensis. These populations are isolated in high mountains, which tends to protect them from the attack of a severe defoliating Mediterranean pest, the pine processionary moth Thaumetopoea pityocampa. However, as a consequence of climate change, the pine processionary caterpillar has increasingly attacked populations of this pine in recent years. This work describes the detrimental effects of defoliation by the pine processionary caterpillar in P. sylvestris subsp. nevadensis in Sierra Nevada. Defoliation strongly reduced pine growth as well as all the reproductive parameters measured (female and male cone production, mature cone size, seed production and seed weight), in addition to some deaths. If winter temperatures continue to increase, the pine processionary caterpillar will have a dangerous impact in these relict pine populations, by further reducing the pine's weak regeneration capacity. We suggest some mitigation actions based on managing habitat structure, in order to reduce or avoid such negative impacts.     

Can alternating temperatures be used to estimate base temperature for seed germination?

Modelling weed seedling emergence pattern appears to be a promising approach in the development of effective weed management programmes based on the selection of optimal timing of control operations. Thermal and hydrothermal time models propose that seed germination rates are proportional to the amount by which temperature and water potential exceed threshold values for these environmental factors. Hence, base temperature for seed germination is a fundamental biological parameter for the prediction of weed emergence. A series of laboratory experiments were conducted to estimate base temperature in three weed species belonging to the Asteraceae family, predominant in conservation tillage fields in north‐eastern Italy. The traditional method based on germination assays at constant temperatures was compared with a method based on assays at alternating temperatures. The latter might represent an alternative to the former for those species which do not germinate or only poorly under constant temperatures. Base temperature was estimated by regressing the reciprocal of the median germination time on temperature comparing two functions, a broken‐stick and an exponential‐type model. Both models showed good fit to all data in the whole temperature range and in almost all cases provided similar estimates of base temperature. The main result is that, for the weed species examined in this study, the use of alternating temperatures for base temperature estimation appears to be possible. However, further research is required to test if the use of germination assays performed at alternating temperatures can be a suitable method to estimate base temperature of species that have too low germination at constant temperatures.     

Simulating winter wheat development response to temperature: Modifying Malo's exponential sine equation

Predicting crop developmental events is fundamental to simulation models and crop management decisions. Many approaches to predict developmental events have been developed, however, most only simulate the mean time for reaching a developmental event. An exponential sine equation developed by Malo [Malo, J.E., 2002. Modelling unimodal flowering phenology with exponential sine equation. Funct. Ecol. 16, 413–418] to predict flower number over time was modified to incorporate the response of crop development rate to temperature. The revised model (ExpSine model) uses the base, optimum, and maximum cardinal temperatures specific to a crop or genotype. Most model parameters were estimated from the literature, and four of the five model parameters have physiological significance. Model evaluation for winter wheat (Triticum aestivum L.) was based on two controlled environment studies from the literature and two field experiments conducted in the North China Plain (NCP) and the Tibet Plateau (TPC). The r² for the modified temperature response function was 0.74 and 0.91 for two different experiments and compared very well (identical mean r²'s) to an existing function (Beta model) [Yin, X., Kropff, M.J., McLaren, G., Visperas, R.M., 1995. A nonlinear model for crop development rate as a function of temperature. Agric. Forest Meteorol. 77, 1–16]. Differences between observed and predicted flowering dates ranged from −2 to 3 days in the NCP and from −7 to 4 days on the TPC, with the mean percent error in both sites less than 1% and no apparent bias observed in the model. This modification of Malo's exponential sine equation expanded the predictive ability of the original equation to simulate phenology across a broader range of environments. The ExpSine model developed can be used as a phenological module in various crop or ecological simulation models.     

桉树抗冻性种质的筛选

云南常年冬天不冷,1982年度冬,一反常态,变成冬季奇寒,低温寡照的气候。不论是冷冬和冬雨,都出现了明显的极值。为了对比方便,将桉树(Eucalyptus)受冻后的生态反映情况分为五级,并以这个标准记录了在云南面积最大,分布最广的4种桉树的受冻情况,其中直干桉(E.maideni)、蓝桉(E.globulus)、大叶桉(E.robusta)、赤桉(E.camaldulensis)在玉溪海拔1680米处的平均受冻级别分别为1.00级,1.06级,1.39级,1.49级,此外还记录了57种按树受害情况。1983、1984到1988年度冬,我们测定了61种桉树的抗冻生理指标,这些室内测定数据,与室外桉树受冻的生态反映级别是基本趋于一致的。因此,根据测定数据,我们将61种桉树的抗冻性分为强、中、弱三等,可为云南桉树的合理布局提供科学依据。