Spontaneous versus colchicine-induced chromosome doubling in maize anther culture

The range of genetic variation of spontaneous chromosome doubling frequency of maize haploid plantlets derived from in vitro anther culture was evaluated. When regeneration is obtained by direct embryo-genesis, bypassing the callus phase, it appears that the frequency of spontaneous doubling may exceed 40 of the regenerated plantlets. This high frequency may be one consequence of the use of doubled haploid lines derived from anther culture and spontaneous chromosome doubling. We also report an increase, by more than 50, of the productivity of diploid fertile regenerated plantlets produced by colchicine supplemented medium during the cold shock pretreatment of the microspores inside the anthers. Optimization of the treatments and the anther culture procedure are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Phytoplankton distribution in the Caspian Sea during March 2001

Phytoplankton abundance, biomass and species composition of the Caspian Sea were evaluated by using samples collected from the Iranian (southern Caspian Sea) and southern Kazakhstan (eastern Caspian Sea) surface waters in March 2001. A total of 45 taxa were found in the samples (20 diatoms, 17 dinoflagellates and 8 others). Abundance and biomass of diatoms were high at the eastern stations, while dinoflagellates were dominant in terms of both biomass and abundance in the southern region. Average abundance and biomass were 40 000 ± 35 000 cell l⁻¹ and 580 ± 690 μg l⁻¹. The mean biomass value found here for the Middle and southern Caspian Sea in March are difficult to compare with the past due to limited information, but seems higher than previously registered values. Higher chlorophyll values were also apparent from the SeaWIFS images in 2001 compared to those in 1998. This is suggested to be due to decreased grazing of phytoplankton by zooplankton which is voraciously preyed by the recent invasive ctenophore Mnemiopsis leidyi.     

Diseases caused by <Emphasis Type="Italic">Ganoderma</Emphasis> spp. on perennial crops in Pakistan

Ganoderma applanatum (Pres. Wallr) Pat. and G. lucidum (Leyss. ex Fr.) Karst attack species of Pinus, Dalbergia, Artocarpus, Morus, Cedrus, Melia, Quercus, Populus and other trees in Pakistan causing stem, butt and root rot diseases. A research institution to manage the diseases of perennial crops in general and of trees yielding edible oil in particular such as coconut and oil palm needs to be established in Pakistan.     

Spatio‐temporal distribution of Ceratitis capitata population in a heterogeneous landscape in Central Italy

The spatio‐temporal dynamics of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), was investigated to evaluate the effect of the landscape elements and host plants on pest distribution, in an agricultural landscape of 500 ha located in Central Italy. Two farms (farm 1 and farm 2) are located in the experimental area, composing mixed fruit orchards and surrounded by hedgerows, small woodlots, private gardens and cereal fields. Ceratitis capitata population fluctuation was monitored, from 2006 to 2008, using traps baited with trimedlure. Geostatistical methods such as Inverse distance squared weighted were used to obtain distributional maps of adults, mainly males. Results showed that the adult Mediterranean fruit flies were primarily distributed inside farm 1, with the maximum density found in the months of September and October. Away from the principal host plants, particularly in cereal fields, the number of trapped individuals was always low or zero. In both farms, flies were caught sequentially in traps located on host plants (i.e. peach, apple, pear, oriental persimmon and prickly pear) at varying times of maturation, especially when fruits remained on the trees. Distributional maps provided evidence that allowed to identify habitats in which the fly developed early in the season (mixed peach orchards) and afterwards during the periodic flights.     

Enhancing the combustible properties of bamboo by torrefaction

Bamboo has wide range of moisture content, low bulk energy density and is difficult to transport, handle, store and feed into existing combustion and gasification systems. Because of its important fuel characteristics such as low ash content, alkali index and heating value, bamboo is a promising energy crop for the future. The aim of this study was to evaluate the effects of torrefaction on the main energy properties of Bambusavulgaris. Three different torrefaction temperatures were employed: 220, 250 and 280 °C. The elemental characteristics of lignite and coal were compared to the torrefied bamboo. The characteristics of the biomass fuels tend toward those of low rank coals. Principal component analysis of FTIR data showed a clear separation between the samples by thermal treatment. The loadings plot indicated that the bamboo samples underwent chemical changes related to carbonyl groups, mostly present in hemicelluloses, and to aromatic groups present in lignin.     

Patterns of reproductive effort in male and female shrubs of Oemleria cerasiformis: a 6-year study

1 We monitored flowering and fruiting of individual male and female plants of Oemleria cerasiformis over a 6-year period in a population in western Canada, and calculated fruit set (percentage of pistils maturing) and reproductive effort (RE) (gram of reproductive tissue per gram of leaf).
2 Over 6 years, male O. cerasiformis had on average much lower total RE, but much higher RE at flowering, than females.
3 In males, strong correlations between RE and light suggested that investment in reproduction was largely determined by light levels. There were strong positive correlations of RE between years, with no evidence of periodic fluctuations.
4 In females, in contrast to males, RE at flowering was not related to light. However, fruit set was strongly correlated with light. Flowering RE and fruit set were uncorrelated in females, indicating that these are affected by different factors.
5 Correlations of RE between years in females, although often significant, were lower than in males, indicating that RE fluctuates more between years in females than in males and may respond to past levels of RE. Flowering may reflect adjustments in response to past reproduction, or may be controlled by resources other than light. Fruit set was not significantly related to previous RE.
6 The greater total RE of females and their limited ability to adjust fruit set are probably major factors contributing to the greater mortality rates of females and the male-biased sex ratios in O. cerasiformis .     

我国3个桉树人工林种植区生产力影响因素

研究影响桉树人工林生产力的主要因素,对于提高桉树人工林生产力以及经营水平和合理利用树种都具有重要的意义。收集我国3个桉树人工林种植区(广东省、广西壮族自治区、云南省)关于生物量与生产力研究中的相关数据,对海拔、林分密度、林龄、年均温和年降水量与乔木层生物量进行了主成分分析与混合模型分析,探究各因素对我国桉树人工林生物量与生产力的影响。结果显示:年均温、年降水量、林龄、海拔和林分密度均是影响广东、广西、云南这3个省(区)桉树人工林生物量的主要因素,其中年降水量对这3个地区桉树人工林的生物量影响极其显著(P0.01),林龄和林分密度对桉树人工林的生物量影响显著(P0.05)。这是因为这3个地区都位于亚热带,温度都属于桉树生长的适宜温度,而这3个地区存在明显的干湿季,降水量在季节和地域上分布不均匀,导致这3个地区年降水量存在较明显的差异。因此,年降水量成为影响这3个地区桉树人工林生物量的关键因素。     

Literature on archaeological remains of cultivated plants (1991/1992)

A total of 422 publications from 1991 and 1992 on archaeological remains of cultivated plants have been collected. A list is given of the finds according to species, country and age.