叶冬:环保VC的旁门秘笈

5月19日,清华创业投资管理有限公司的总裁叶冬从华盛顿飞回了北京.一路上,他难掩心中的激动和兴奋.

Effects of Drought Stress on the Photoprotection in Ammopiptanthus mongolicus Leaves

Ammopiptanthus mongolicus (Maxim.) Cheng f. is one of the evergreen shrubs in the desert region of China. In midday its leaves bear photon flux density over 1 500 μmol·m -2 ·s -1 at natural habitat. They show the obvious phenomenon of photoinhibition. For the study of the effects of drought stress on the major protective mechanism against strong light in A. mongolicus leaves, the diurnal variations of photosynthetic rate and chlorophyll fluorescence parameters were investigated under natural conditions with portable photosynthetic measurement system (CIRAS_1) and portable fluorometer (MFMS_2). The experimental results showed that, under normal and drought stress conditions,the net photosynthetic rate ( Pn ), the primary maximum photochemical efficiency of PSⅡ ( Fv/Fm ) and the quantum efficiency of noncyclic electron transport of PSⅡ ( Φ PSⅡ ) decreased obviously at noon (Figs.2,3A,4B). In comparison with plants under normal condition, under drought stress minimal chlorophyll fluorescence ( Fo ) decreased at first and then increased (Fig.3A), non_photochemical quenching ( NPQ ) quickly increased and sustained at a higher level (Fig.4B). This indicated that the major photoprotective mechanism of A. mongolicus leaves was the xanthophyll cycle_dependent thermal energy dissipation under normal condition, while under drought stress, the major photoprotective mechanism was both the xanthophyll cycle_dependent thermal energy dissipation and the reversible inactivation of PSⅡ reaction center.

Effect of Heat Stress on Photosynthetic Characteristics of Different Green Organs of Winter Wheat During Grain-filling Stage

Four winter wheat (Triticum aestivum L.) varieties ('JD 8', 'Jing 411','Centurk' and 'Tam 202') were used to study the effect of heat stress on photosynthetic characteristics of flag leaf blade, nag leaf sheath, peduncle, glume, lemma and awn during grain-filling stage. The results showed that heat acclimation during grain-filling stage increased thermotolerance of wheat with significant differences among different green organs. During heat stress, the decreases of the efficiency of primary light energy conversion (F-v/F-m) of PS II and pigment (chlorophyll and carotenoid) content were much slower in peduncle, flag leaf sheath and glume than in nag leaf blade, lemma and ann; and the percentage of decrease in net photosynthetic rate (P-n) of ear was lower than that of the nag leaf blade. The measured photosynthetic parameters (F-v/F-m, P-n and pigment content) of 'JD 8', a relatively heat tolerant variety, declined more slowly than those of the other three varieties during the whole heat stress period.

Changes of Gas Exchanges in Leaves of Different Cultivars of Winter Wheat Released in Different Years

Three winter wheat cultivars ( Triticum aestivum L.), representatives of those widely cultivated in Beijing over the past six decades, were grown in the same environmental condition, and their physiological features were investigated. Daily changes of net photosynthetic rate (P-n), transpiration (T-r) in different growth stages were measured in order to find the relationship between leaf photosynthesis and yield. Instantaneous water use efficiency (WUE) of leaf was calculated from P-n/T-r. It is suggested that relationship between photosynthetic rate and yield changed with the developing stages of wheat. High yield wheat cultivar Jingdong 8 (released in the 1990s) had a higher photosynthetic rate ( the maximal P-n increased by 77%) and transpiration rate (the maximal T-r increased by 69%), but a lower WUE than the low yield cultivar Yanda 1817 (released in the 1940s) during the day time at stem elongation stage. However; difference of P-n among the three cultivars changed with wheat growth process. Before 10 o'clock P-n in leaves of Jingdong 8 usually was the highest of the three cultivars, but P-n of Yanda 1817 was the highest after 10 o'clock. At dough ripe stage, P-n in leaves of Yanda. 1817 was the highest among the three cultivars during the whole day. The difference of changing trend of transpiration in three wheat cultivars was similar to P,, but WUE of Yanda 1817 was the highest in those three cultivars, indicating that the higher yield of Jingdong 8 was achieved via a greater consumption of water. Contrary to the cultivars released in the later period, midday depression of photosynthesis was small in Yanda 1817, which might suggest that Yanda 1817 was resistant to photoinhibition. It is possible that photosynthetic potential in leaves of wheat increased as wheat cultivars was improved over the past six decades. However, it became less resistant to photoinhibition.

Effects of spatio-temporal and environmental factors on distribution and abundance of wintering anchovy Engraulis japonicus in central and southern Yellow Sea

We investigated the spatio-temporal and environmental factors that affect the distribution and abundance of wintering anchovy and quantifi es the infl uences of these factors. Generalized additive models(GAMs) were developed to examine the variation in species distribution and abundance with a set of spatiotemporal and oceanographic factors, using data collected by bottom trawl surveys and remote sensing in the central and southern Yellow Sea during 2000–2011. The fi nal model accounted for 28.21% and 41.03% of the variance in anchovy distribution and abundance, respectively. The results of a two-step GAM showed that hour, longitude, latitude, temperature gradient(TGR), and chlorophyll a(Chl- a) concentration best explained the anchovy distribution(presence/absence) and that a model including year, longitude, latitude, depth, sea surface temperature(SST), and TGR best described anchovy abundance(given presence). Longitude and latitude were the most important factors affecting both distribution and abundance, but the area of high abundance tended to be east and south of the area where anchovy were most likely to be present. Hour had a signifi cant effect on distribution, but year was more important for anchovy abundance, indicating that the anchovy catch ratio varied across the day but abundance had an apparent interannual variation. With respect to environmental factors, TGR and Chl- a concentration had effects on distribution, while depth, SST, and TGR affected abundance. Changes in SST between two successive years or between any year and the 2000–2011 mean were not associated with changes in anchovy distribution or abundance. This fi nding indicated that short- and long-term water temperature changes during 2000–2011 were not of suffi cient magnitude to give rise to variation in wintering anchovy distribution or abundance in the study area. The results of this study have important implications for fi sheries management.

Harmfulness of Leaf Miners （Agromyzidae） on Winter Wheat Plantations in Poland

The aim of the study was to determine the harmfulness of leaf miners and their species composition on winter wheat for the improvement of methods to control them. In order to determine the dates of the treatments, it was necessary to catch adult flies. The researchers used yellow 25 x 40 cm sticky traps placed on three control plots to catch the adults. Monitoring of cereal leaf miners flights in winter wheat was carried out in Babor6wko （greater Poland voivodeship）. Yellow traps were placed above the tops of wheat during vegetation period. The number of damaged wheat stems was recorded. Fluctuations in weather conditions during the research affected the dynamics of leaf miner flies considerably. The maximum flights of leaf miner flies on winter wheat crops in years of the studies took place in May. The dynamics of leaf miners flights were different in growing season 2008 and 2009. The most common species were： Chromatomyia nigra （Ztt.）, Chromatomyia fuscula （Ztt.） and Poemyza superciliosa （Ztt.）. It was also discovered that the species composition of Agromyzidae damaging the winter wheat, changes in particular years. The results differ from the results of the previous research, which the dominant species were Phytomyza nigra （Mg.） and Agromyza ambiqua （FII.）.

Study on the production effect and prevention index of the forthputting of sonsau cocuus sinensis chen on the Pinus tabulaeformis

The growth of Pinus tabulaeformis is influenced by the sonsau cocuus sinensis chen. When the insect density is more than 300-350 head/hundred beam conifer, sonsau cocuus sinensis chen occurred significantly influence the Pinus tabulaeformis＇ s growth. when the insect density reached 250-300 head/100 beam coniferous, sonsau cocuus sinensis chen significantly influence the accumulation of Pinus tabulaeformis volume. To determine the sonsau cocuus sinensis chen 2nd instar nymph theory control index was 220.5 / hundred beam needles has a guiding significance to the production practice.

Evapotranspiration and ratio of soil evaporation to evapotranspiration of winter wheat and maize in north China

Evapotranspiration （ETc） is an important quantity for hydrological cycle. This study shows evapotranspiration, the ratio of evaporation to evapotranspiration （E/ETc） of winter wheat and maize in north China. Several relationships, namely, E/ET0 and soil surface moisture, E/ET0 and leaf area index （LAI）, are also analyzed. The average seasonal ETc values for winter wheat, maize （2008） and maize （2009） are 431.21,456.3 and 341.4mm. The value of E/ET0 varied from 1 at initial growth stage to 0.295 at the later growth for winter wheat, and from 1 to 0.492, from 1 to 0.566 for maize （2008） and maize （2009）. The relationship between E/ET0 and surface soil water content, and E/ET0 and LAI are fitted to a quadratic parabola equation with significant correlation coefficients, respectively, for wheat and maize. These results should help the precise planning and efficient management of irrigation for these crops in this region.

Impact of Cutting a Clover Crop on the Nitrogen Supplied to Winter Wheat in an Intercropping System

The major function of clover in a winter wheat–white clover intercropping system is to supply nitrogen （N） for the wheat. A field experiment was conducted at Yucheng Comprehensive Station of the Chinese Academy of Sciences, to evaluate the effect of cutting white clover on N fixation and the transfer of fixed N to the associated winter wheat. A method of 15N natural abundance was used to determine the nitrogen dynamics in the intercropping system. The results showed that the amount of N transferred from the clover to the wheat, throughout the growing season, varied between 34.4 and 57.5 kg ha-1. Compared to leaving the clover standing, cutting the clover increased the amount of N that accumulated in the soil and also resulted in reduced N concentrations in the leaves and stems of the wheat. Using the cut clover as mulch between wheat rows led to decreased N concentrations in the wheat plants’ leaves and stems. The present study provides preliminary information on the amount of N transferred from clover to wheat in an intercropping system.

Decomposition of Surface-Applied and Soil-Incorporated Bt Maize Leaf Litter and Cry1Ab Protein During Winter Fallow in South Africa

Unintended effects of genetic modification on chemical composition of Bt maize leaf litter may have impacts on its decomposition. In most agricultural systems in South Africa, maize litter is either left on the soil surface or incorporated into the soil during tillage. A litterbag experiment, using leaf litter of three maize hybrids （DKC80-12B, DKC80-10 and DKC6-125）, was carried out at the University of Fort Hare Research Farm, South Africa, to determine the effects of genetic modification on decomposition of maize leaf litter when left on the soil surface under field conditions between July and November, the normal fallow period, in 2008. Another litterbag experiment was conducted at the University of Fort Hare Research Farm and Zanyokwe Irrigation Scheme, South Africa, using leaf ~itter of two maize hybrids genetically modified with the erylAb gene （MONS10）, DKC75-15B and PAN6Q-3OSB, and their corresponding near isolines, CRN3505 and PAN6Q-121. The degradation of CrylAb protein in the litter, both surface-applied and soil-incorporated, was also investigated. Decomposition of Bt maize litter was similar to that of non-Bt maize litter both when applied on the surface and when incorporated into soil. Soil-incorporated litter, as well as its CrylAb protein, decomposed faster than that applied on the surface. The leaf litter C：N ratios of PAN6Q-308B and PAN6Q-121 were similar throughout the study, whereas those of DKC75-15B and CRN3505 declined by similar amounts during a 12-week period. These findings suggested that decomposition of leaf litter of Bt maize, with the MON810 event, was not affected by maize genetic modification, and that the CrylAb protein broke down together with plant leaf litter during the winter fallow regardless of whether the litter was applied on the soil surface or incorporated into soil.