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101.
102.
Allelopathic potential of watermelon in hydroponic culture was investigated using the continuous root exudates trapping system (CRETS). Laboratory bioassays and high-performance liquid chromatography (HPLC) were used for quantification of phytotoxins in different plant tissues and root exudates collected using XAD-4 resin. Seedling growth of both watermelon and lettuce was significantly inhibited by watermelon root exudates and the degree of inhibition increased with increasing concentration of exudates. Root exudates had inhibitory effects throughout the experiment and these were most pronounced during the period 41–50 days after transplanting. Inhibitory effects of various plant tissues were demonstrated using the bioassay tests. Frulic acid was the dominant component found using HPLC and the amounts of allelochemicals found in the plant extracts were correlated with the bioassay results using the Petri dish test. The results indicate that the allelopathic potential of watermelon may play an important role in the phenomenon referred to as ‘soil sickness’. 相似文献
103.
Aetiology of Rhizoctonia in sheath blight of maize in Sichuan 总被引:1,自引:0,他引:1
Rhizoctonia isolates obtained from maize grown in commercial fields in 33 representative counties (or cities) in Sichuan province in China were characterized according to colony morphology, hyphal anastomosis and pathogenicity. Of 141 isolates, 116 were identified as R. solani , 23 as R. zeae and two as binucleate Rhizoctonia . The isolates of R. solani were assigned to four anastomosis groups (AG): AG-1-IA (101 isolates, accounting for 71.6% of the total), AG-1-IB (2, 1.4%), AG-4 (9, 6.4%) and AG-5 (4, 2.8%). The two isolates of binucleate Rhizoctonia belonged to AG-K. On maize, isolates of AG-1-IA caused typical sheath blight symptoms. Lesions produced by isolates of AG-4, AG-5, AG-1-IB and AG-K were darker than those of AG-1-IA. Rhizoctonia zeae usually caused discontinuous lesions with a dark brown margin and a brown centre on the leaf sheaths, as well as ear rot. Isolates of AG-1-IA were the most virulent to maize, with an average lesion length of approximately 15 cm. Isolates of R. zeae produced lesions approximately 12 cm long, while those of AG-4, AG-5, AG-1-IB and AG-K were progressively shorter. On potato dextrose agar (PDA; pH 6.4), the minimum temperature for mycelial growth of R. zeae isolates was 14–18°C, the maximum 38–40°C and optimum 30°C. Isolates of R. zeae did not grow on PDA (28°C) at pH 2.0, the optimum for growth being pH 6.4. 相似文献
104.
Partitioning of propofol between blood cells, plasma and deproteinised plasma in sheep 总被引:1,自引:0,他引:1
B. M. Q. Weaver G. E. Staddon† D. Raptopoulos W. W. Mapleso‡ 《Veterinary anaesthesia and analgesia》1998,25(1):19-23
The partitioning of propofol within the blood, when administered in its usual emulsion carrier, has been determined in vitro in sheep. The blood:plasma ratio was found to be 1.13 and the blood-cell:plasma ratio 1.42. When oxalate was used as the anticoagulant, the plasma protein binding was calculated to be 92.6% - slightly lower than reported for dog, rat, rabbit and man. However, when heparin was the anticoagulant, the binding was significantly less, 83.0%. Differences from some results in the literature may be attributable to other workers using propofol without the lipid emulsion carrier. From the results of this study it is argued that anaemia and plasma levels of protein and lipid may affect propofol requirements. 相似文献
105.
106.
To investigate the variations of active compounds between species, varieties and individuals of Valeriana cultivated under the same environmental condition, the contents of valerenic acid derivatives and valepotriates in rhizomes and roots of different plant material were analysed by a HPLC method. Different species or varieties of Valeriana yielded 11.65-0.15 mg/g of valerenic acid derivatives, and 1.81-0.03 mg/g of valepotriates. The variation between individuals of one commercial cultivar of V. officinalis ranged from 12.34 to 3.01 mg/g of valerenic acid derivatives, and 3.67-0.92 mg/g of valepotriates. Individuals from self-pollinated mother plants, normal or regenerated, showed a similar variation. The variation of micropropagated plants was much less than the seed propagated plants. The ratio of mean values between valerenic acid derivatives and valepotriates was similar in all groups (3 < ratio < 8) except one group of micropropagated plants (ratio > 20). 相似文献
107.
108.
Intercropping of Corn with Soybean and Lupin for Silage: Effect of Seeding Date on Yield and Quality
B. Prithiviraj K. Carruthers Q. Fe D. Cloutier R. C. Martin D. L. Smith 《Journal of Agronomy and Crop Science》2000,185(2):129-136
Intercropping of corn with legumes is an alternative to corn monocropping and has a number of advantages, for example, lower levels of inputs, lower costs of production and better silage quality than the monocrop system. An experiment was carried out at two sites in 1993 and 1994 to investigate the effects of seeding date (simultaneous with corn or 3 weeks later) and number of rows of large‐seeded legumes (one or two) seeded between the corn rows. The intercrop plots received 90 kg ha?1 less nitrogen fertilizer than the monocrop plots, which received 180 kg ha?1. Silage yields were sometimes decreased by the simultaneous seeding of corn and large‐seeded legumes. Protein content and concentration were not affected by most treatments and provided reasonable quality silage, despite a reduction in the amount of nitrogen fertilizer used. 相似文献
109.
The benzimidazole anthelmintic agents-a review 总被引:4,自引:0,他引:4
110.
The grain yield of normal oil maize (Zea mays L.) might increase when pollinated by high oil maize (HOM) hybrids because of heterosis. To testify that the grain yield increase might be a result of improved photosynthetic rate and related traits, the normal oil maize (NOM) hybrid, Nongda108, was cross-pollinated by three HOM hybrids, HOM202, HOM115 and HOM4515 (for short as ND108pHOM202, ND108pHOM115 and ND108pHOM4515). We found that the ND108pHOM202 and ND108pHOM115 exhibited higher net photosynthetic rate (Pn), accompanied by larger stomatal conductance (gs) and transpiration rate (E). Moreover, delayed leaf senescence was observed in their leaves, including larger leaf area index (LAI) and higher Chl content and Chl a/b ratio. Apart from higher phosphoenolpyruvate carboxylase (PEPCase) activity, the soluble proteins were also higher in the two cross-pollinations. The higher leaf photosynthesis could explain the grain increase in ND108pHOM202 and ND108pHOM115. However, ND108pHOM4515 exhibited a decreased photosynthetic characteristic and yield performance. Significantly positive relation between grain yield and biomass (r2 = 0.96, P < 0.05), Pn and biomass (r2 = 0.74, P < 0.05) also suggested that the yield increase in the two cross-pollination treatments was generally owing to the higher photosynthetic rate and related photosynthetic traits. 相似文献