基于PLC和嵌入式的智能农场

为应对农场规模日益增长的需求,文中以可编程逻辑控制器(PLC)和嵌入式STM32相结合作为控制核心,使用土壤湿度传感器、光照度传感器、空气质量传感器等采集温室农场农作物的生长环境因素数据,并通过摄像头监控农作物的生长情况。室外农场使用PLC控制水泵电机对农作物定时喷洒,家畜养殖场则通过控制闸门的开、关来实现定时喂养,从而达到对整个农场的智能化处理。智能农场可以减少人力、物力的投入,提高工作效率及生产产值,有很大的发展前景。

COMBINED EFFECTS OF TEMPERATURE, IRRADIANCE AND SALINITY ON GROWTH OF DIATOM SKELETONEMA COSTATUM

factor experiment was used to study the combined effects of temperature, irradiance and salinity on the growth of an HAB species diatom Skeletonema costatum (Grev.) Cleve. The results showed that temperature (12, 19, 25, 32℃), irradiance ((0.02, 0.08, 0.3, 1.6)×10 16 quanta/(s·cm 2)) and salinity (10, 18, 25, 30, 35) significantly influenced the growth of this species. There were interactive effects between any two of and among all three physical factors on the growth. In the experiment, the most optimal growth condition for S. costatum was temparature of 25℃, salinity of 18-35 and irradiance of 1.6×10 16 quanta/(s·cm 2). The results indicated S. costatum could divide at higher rate and were more likely to bloom under high temperature and high illumination from spring to fall. It was able to distribute widely in ocean and estuary due to its adaptation to a wide range of salinities.

Significant Effects of Fishing Gear Selectivity on Fish Life History

Over the past few decades, extreme changes have occurred in the characters of exploited fish populations. The majority of these changes have affected the growth traits of fish life history, which include a smaller size-at-age, an earlier age-at-maturation and among others. Currently, the causes of these life history traits changes still require systematic analyses and empirical studies. The explanations that have been cited are merely expressed in terms of fish phenotypic adaptation. It has been claimed that the original traits of fish can be recovered once the intensity of exploitation of the fish is controlled. Sustained environmental and fishing pressure will change the life history traits of most fish species, so the fish individual's traits are still in small size-at-age and at earlier age-at-maturation in exploited fish populations. In this paper, we expressed our view of points that fishing gear has imposed selectivity on fish populations and individuals as various other environmental factors have done and such changes are unrecoverable. According to the existing tend of exploited fish individual's life history traits, we suggested further researches in this field and provided better methods of fishery management and thereby fishery resources protection than those available early.

Colloid's influences on microalgae growth as a potential environmental factor

The role of colloid as “colloid pump” in the ocean is well known. The important influence of colloid in seawater on the growth of microalga was found in our 1999—2000 study. Colloid concentrates were obtained by employing a cross flow filtration system to ultrafilter seawater (which had been pre filtrated by 0.45 μm acetate cellulose membrane) successively with different membranes. Ultrafiltration retentions (we called them colloid concentrates) together with control sample (seawater without colloid) were then inoculated with two species of microalgae and cultivated in selected conditions. Monitoring of microalgae growth during cultivation showed that all colloid concentrates had obvious influence on the growth of the microalgae studied. Addition of Fe(OH) 3 colloid or organic colloid (protein or carbohydrate) to the control sample enhanced the microalgae’s growth.

Research of Influence of Aniline on the Growth of Ocean Algae

This article discusses the interaction of aniline and ocean algae based on the standard appraisal method of chemical medicine for algae toxicity. It is showed by experimental results that aniline has pretty toxic effects on algae. Suspended substances in water can offset some effects of aniline. It also discusses the dynamic constant of first order degradation reaction rate of algae on aniline from the point of view of chemical dynamics.

Flowering responses to light and temperature

Light and temperature signals are the most important environmental cues regulating plant growth and development. Plants have evolved various strategies to prepare for, and adapt to environmental changes. Plants integrate environmental cues with endogenous signals to regulate various physiological processes, including flowering time. There are at least five distinct pathways controlling flowering in the model plant Arabidopsis thaliana: the photoperiod pathway, the vernalization/thermosensory pathway, the autonomous floral initiation, the gibberellins pathway, and the age pathway. The photoperiod and temperature/vernalization pathways mainly perceive external signals from the environment, while the autonomous and age pathways transmit endogenous cues within plants. In many plant species, floral transition is precisely controlled by light signals(photoperiod) and temperature to optimize seed production in specific environments. The molecular mechanisms by which light and temperature control flowering responses have been revealed using forward and reverse genetic approaches. Here we focus on the recent advances in research on flowering responses to light and temperature.

Environmental factors determining growth of salamander larvae： A field study

Larval growth and survival of organisms are strongly influenced by abiotic and biotic factors, as demonstrated by ex- perimental studies performed under controlled laboratory or semi-natural conditions. Even if they have many advantages, ex- periments cannot cover the full complexity of natural conditions and field studies are needed for a better understanding of how environmental variation determines growth and development rate. Fire salamander Salamandra salamandra females give birth to larvae in a variety of habitats, both epigean and subterranean. In caves, salamander larvae successfully grow and metamorphose, but their growth is more than three times longer than in epigean streams and factors determining these differences require inves- tigation. We performed a field study to understand the factors related to the growth of fire salamander larvae in different envi- ronmental conditions, evaluating the relationship between environmental features and larval growth and differences between caves and epigean spring habitats. Both caves and epigean larvae successfully grew. Capture-mark-recapture allowed to individu- ally track individuals along their whole development, and measure their performance. Growth rate was significantly affected by environmental variables： larvae grew faster in environments with abundant invertebrates and few conspeciflcs. Taking into ac- count the effect of environmental variables, larval growth was significantly lower in caves. Food availability plays a different ef- fect in the two environments. Larval growth was positively related to the availability of invertebrates in epigean sites only. The development rate of hypogeous populations of salamanders is slower because of multiple parameters, but biotic factors play a much stronger role than the abiotic ones