麦秸覆盖夏玉米对其苗期生长发育的生化他感作用研究初报

麦秸覆盖夏玉米对其苗期生长发育的生化他感作用研究初报张玉铭,马永清（中国科学院石家在农业现代化研究所,０５００２１）ＡｌｌｅｌｏｐａｔｈｉｃＥｆｆｅｃｔｏｆＷｈｅａｔＳｔｒａｗＭｕｌｃｈｉｎｇｏｎＳｅｅｄｌｉｎｇＧｒｏｗｔｈａｎｄＤｅｖｅｌｏｐｍｅｎ...     

Phytotoxicity from plant residues

Summary Proximity of new wheat straw residues to sown wheat seed has an effect on germination, plant growth and ultimate yield. Decomposition of wheat straw may produce toxins or it may cause immobilization of nitrogen in, or applied to the soil. In pot experiments, it has been shown that germination of wheat was depressed when large amounts of straw were decomposed on the surface for up to 18 days; after 54 days it had no effect on germination. Immobilization of nitrogen occurred mainly when the straw was mixed with the soil, or when surface-rotted straw was ploughed into the soil just before seeding. The latter effect could not be overcome by the addition of mineral nitrogen. Part II, Plant and Soil 38, 347–361 (1973).     

小麦秸秆水浸提液对五种植物化感作用的研究

该文研究了不同浓度的小麦秸秆水浸提液对徐州地区2种玉米(郑单958和农大108)和3种常见玉米田间杂草(马唐、稗草和反枝苋)种子萌发和幼苗生长的影响。结果表明:当小麦秸秆浸提液浓度分别大于75、50和25 g·L~-1时,马唐、稗草和反枝苋种子的萌发受到显著的抑制;当小麦秸秆浸提液浓度分别大于50和37.5 g·L~-1时,玉米郑单958和农大108种子的萌发受到显著的抑制;但当小麦秸秆浸提液浓度大于37.5 g·L~-1时,马唐、稗草和反枝苋幼苗根和芽的生长均受到明显的抑制;当小麦秸秆浸提液浓度小于75 g·L~-1时,玉米郑单958和农大108幼苗根与芽的生长受到明显的促进,且郑单958幼苗叶片中叶绿素的含量以及郑单958的POD酶活性均得到提高。该研究结果表明较高浓度的小麦秸秆浸提液(50 g·L~-1)会抑制杂草的生长,有利于玉米郑单958的生长,为小麦秸秆还田和玉米田杂草的生态防治提供了理论基础。     

Beta-adenosine, a bioactive compound in grass chaff stimulating mushroom production

Fructification and yield of the edible mushrooms Pleurotus pulmonarius and Stropharia rugosoannulata are clearly enhanced when wheat straw is supplemented with 30% Lolium perenne grass chaff. The bioactive compound in the methanol extract of grass chaff was identified as beta-adenosine. In vitro biological activity tests showed that 0.012 mg of beta-adenosine per ml of medium stimulated earlier fructification of Pleurotus pulmonarius. Mushroom fruiting trials showed that when 12 mg beta-adenosine was added to 1 kg wet wheat straw, primordia of Pleurotus pulmonarius appeared two days earlier and primordia of Stropharia rugosoannulata appeared 18 days earlier when compared to pure wheat straw substrate. This concentration of beta-adenosine had no impact on the mushroom yield of Pleurotus, but resulted in a 2.2 fold increase in yield for Stropharia. beta-Adenosine at 25 mg per kg wet wheat straw increased the yield of Pleurotus with 52% and the yield of Stropharia with 258%, but this concentration delayed primordial formation in Pleurotus.     

Studies on biological decomposition of wheat straw

Summary The incorporation of undecomposed wheat straw in the soil along-with the micro-organisms favourably increased the yield of groundnut crop. An increase of 37 per cent in yield was recorded when wheat straw was inoculated withPenicillium digitatum and the C:P ratio was adjusted to 65. Inoculated treatments of narrower C:P ratio gave a higher yield than wider C:P ratio treatments inoculated with the same cultures. An increase in nitrogen uptake by groundnut plants was recorded due to incorporation of straw alongwith the micro-organisms in soil. The organic carbon and nitrogen content of the soil increased with all the treatments except control. The highest increase in organic carbon and nitrogen of the soil was observed with a treatment of wheat straw of 65 C:P ratio inoculated withS. coccosporum. The yield of wheat crop after groundnut was significantly more with several treatments than control plots. The highest increase of 79 per cent in grain yield of wheat was observed in the plots previouslq received with wheat straw of 200 C:P ratio.This paper is based on the data presented at IV Southern Regional Conference on Microbial Inoculants, held at Parbhani during 3–4 July 1978.     

麦秸与稻秸浸提液对油菜及2种靶标杂草种苗生长影响的差异性研究

采用室内培养皿生物测定的方法,测试不同质量浓度（0、0.02、0.03、0.05、0.08、0.10 g·mL^-1）麦秸、稻秸浸提液对油菜及油菜田2种常见靶标杂草野燕麦（Avena fatua Linn）、播娘蒿 ［Descurainia sophia（L.）Schur］种子萌发及幼苗生长的影响。结果表明,在供试质量浓度下,麦秸与稻秸浸提液对3种受体材料种苗生长的影响存在显著差异,二者对油菜种苗生长安全的最高质量浓度分别为0.08 g·mL^-1和0.05 g·mL^-1,可以用来开发研制油菜田肥料;在对油菜安全的质量浓度下,麦秸浸提液对野燕麦种苗生长无抑制作用;而稻秸浸提液对野燕麦种苗生长的抑制作用明显,可以用来开发研制油菜田防除野燕麦的生物抑草肥;在油菜的安全的质量浓度下,麦秸、稻秸浸提液对播娘蒿种苗生长均有很强的抑制作用,且麦秸的抑制作用强于稻秸,具有开发研制油菜田治理播娘蒿的生物抑草肥料的应用前景。     

Phytotoxicity from plant residues

Summary Cold aqueous extracts of several grasses and legumes that had been rotted for periods up to 21 days have been shown to inhibit the growth of wheat grown under aseptic conditions. The degree of inhibition varied from one species to another and also with rotting period. Straws which were cut while still green produced a higher level of toxicity than those cut when fully matured. Growth of roots was inhibited more than that of shoots and generally the degree of inhibition decreased with time of rotting. All toxic extracts showed a trough in conductivity values during rotting. Values of pH increased with period of rotting, generally up to pH 8.0–8.5.Toxic extracts contained material of a large range of molecular weights. However, the most toxic material from extracts of rye straw rotted for 4 days had molecular weights from 10,000 to 50,000.Part I,Aust. J. agric. Res., 1967,18, 361.     

Germination of conidia ofVerticillium dahliae in soil

Summary A study was made of the effect of soil fungistasis on the germination of conidia ofVerticillium dahliae Kleb. Conidia germinated on steam or propylene oxide sterilized soil, but not on unsterilized soil of six types tested. Peptone (0.5 per cent) nullified fungistasis. Glucose (0.5 per cent) had no effect on fungistasis. Wheat straw or lignin amended to unsterilized soil had no effect on spore germination after sterilization. Fungistasis was restored to sterilized soil by incorporating natural soil at various ratios or by lowering the soil pH. Fungistasis was also restored by incubating various micro-organisms in sterile soil. The fungistasis so obtained was nullified by incorporation of nutrients or by sterilization. The results suggest that nutrient deficiency as well as inhibitory substances of microbial origin might play a role in soil fungistasis. 5012 plant and soil     

Studies on the Germination of Cereals: 4. The Oxygen Requirement for Germination of Wheat Grains during Maturation

The oxygen required by the wheat embryo, for germination atdifferent stages of maturation, has been determined by the numberof grains with the embryo exposed which germinated in differentoxygen concentrations. Some embryos required only 0.5 per cent.,and the majority required less than 5 per cent., but there wasalso a proportion which required a concentration approachingthe level in air. There were more embryos in the last categoryin the grains of a red variety than in those of a white varietybut this did not account for the varietal difference in germinationwhen the grains were intact. The effect of the covering layers was also determined in eachatmosphere by the difference in germination between intact grainsand grains with the embryo exposed. The covering layers weresufficiently impermeable to prevent germination in both varietieswhen the external oxygen concentration was very low; when theconcentration was increased from 5 to 60 per cent., however,the inhibiting effect of the covering layers was reduced inthe white variety but not in the red. The delayed germinationof the red grains was therefore attributed to some factorotherthan the impermeability of the covering layers to oxygen.     

Tolerance of wheat and pea to boron in irrigation water

In a micro-plot experiment 1.5 ppm boron in the irrigation water was toxic for wheat. Its concentration in the soil solution increased to 1.53 ppm and in the plant tissue to 58 ppm. In pea plants 4 ppm B in the irrigation water was toxic with 2.00 ppm soil solution B and 213 ppm tissue B. Nitrogen in both species increased significantly and calcium decreased with the increase in B in irrigation water. The yield of wheat grain declined by 13, 20 and 32 per cent at the 4.0, 6.0 and 8.0 ppm B respectively. The yield of straw and grains of pea declined by 31, 56 and 41, 56 per cent at 6.0 and 8.0 ppm B levels respectively. Thus tolerance to B in irrigation water was between 3.0 and 4.0 ppm for wheat and 4.0 and 6.0 ppm for pea.     

Changes in Nicotinic Acid Content and Its Nucleotide Derivatives of Rice and Wheat Seeds during Germination

Relative distribution of bound and free forms of nicotinic acid in rice and wheat seeds and their metabolism during germination were the subject of the present investigation. Measurement of the levels of NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate) formed another part of the work. Total nicotinic acid in both rice and wheat increased with germination and was maximum at 72 hours. From this time onwards, it began to decline rapidly and at the end of experiment, i.e., after 120 hours, it was lower than that for ungerminated seeds on per seedling basis, although it was slightly higher on per g dry weight basis. Ungerminated seeds of wheat and rice contained about 89 per cent and 80 per cent respectively of their total nicotinic acid in bound form which became partially free in course of germination. Total nucleotides (oxidised plus reduced forms) increased progressively up to 96 hours followed by a slight fall at 120 hours. NAD reached a maximum at 24 hours and fell gradually thereafter. The depletion of NAD was associated with a progressive accumulation of NADH. NADP decreased from the peak value at 72 hours. Formation of NADP and its maintenance at high level depend on NAD in the oxidised form and the content slowed down in tissues with higher NADU/NAD ratio. A relatively large amount of NADPH was present throughout the experiment.     

Barley straw as an inhibitor of algal growth II: laboratory studies

The presence of rotting barley straw in water inhibited the growth of several planktonic and filamentous algae in laboratory culture. The inhibitory effect was produced progressively during decomposition of the straw at 20 °C and reached a maximum after six months. When the straw was autoclaved, all inhibitory activity was lost. Algae recovered and continued to grow normally when transferred from cultures containing rotting straw to sterile culture medium. Addition of liquor from rotting straw also inhibited algal growth. The capacity to inhibit growth remained in the liquor after passage through a 0.2 ,m filter but was removed by activated carbon. The inhibitory effect of straw shows promise as a practical means of limiting the growth of a range of algae which can cause problems in aquatic systems.author for correspondence     

秸秆全量还田对稻田土壤溶解有机碳含量和水稻产量的影响

以南粳44为供试材料,在粘土和砂土土壤中,设置麦秸秆不还田和全量还田(6000 kg·hm^-2)及3种施氮量(0、225、300 kg·hm^-2)试验,研究了麦秸秆全量还田的腐解率和有机碳释放量动态变化,及其对稻田0～45 cm土壤溶解有机碳(DOC)含量和水稻产量的影响.结果表明： 麦秸秆还田的前期(0～30 d)其腐解率和有机碳释放量最高,腐解率为35.0%(粘土)和31.7%(砂土),有机碳释放率为34.1%(粘土)和33.1%(砂土);30 d后两者均减小.施用氮肥可显著促进秸秆腐解和有机碳释放量,粘土中麦秸秆腐解率和有机碳释放量明显大于砂土.麦秸秆还田后土壤DOC含量逐渐增加,至25 d达最大值,粘土和砂土分别为60.18和56.62 mg·L^-1,此后逐渐减小并趋于稳定.麦秸秆还田处理15 cm处土壤DOC含量显著高于未还田处理,但两者在30和45 cm处土壤DOC含量差异不显著,说明秸秆还田主要增加了稻田0～15 cm土层DOC含量.与不施氮处理相比,施氮处理土壤DOC含量降低,2种施氮处理间差异不显著.秸秆还田减少了水稻前期分蘖发生量,显著降低了有效穗数,增加了穗粒数、结实率和千粒重,显著提高了水稻产量.     

Influence of organic soil amendments on Verticillium dahliae and on the microbial composition of the strawberry rhizosphere

A technique was developed for assessing the saprophytic activity of Verticillium dahliae, using a strawberry root extract medium. The germination of conidia and microsclerotia, and mycelial growth in soil, was inhibited by the addition of chitin, laminarin, wheat straw and oven-dried green clover as soil amendments. A significant decrease in the number of viable propagules of the pathogen counted from soil, and in disease severity, was obtained with chitin and laminarin. More bacteria and actinomycetes were recorded from the rhizosphere of plants grown in chitin-amended soil than from those in natural soil.     

Production, Partial Purification and Characterization of Extracelluar Xylanase from Chaetomium globosum

Culture conditions for efficient production of extracellular xylanase by fungus, Chaetomium globosum isolate Cg2, have been standardized. Further, xylanase has been partially purified and characterized. Xylanase activity was maximum after 9 days of incubation when amended in medium with 1.5 % xylan as carbon source and 0.6% NH₄H₂PO₄ as nitrogen source. Partial purification of the xylanase was accomplished by ammonium sulphate precipitation, followed by further purification by anion exchange chromatography on DEAE-Sephadex A-50 column. The partially purified enzyme was electrophoresed on SDS-PAGE and a single band produced corresponded to molecular weight, 32 kD. The optimum temperature and pH for maximum activity of purified xylanase were 30°C and 5.5, respectively. Both the purified xylanase and culture filtrate have shown the antifungal activity against Bipolaris sorokiniana, a causal organism of spot blotch of wheat. Purified xylanase at 100 μg ml^?1 concentration caused 100 per cent inhibition of conidia germination of B. sorokiniana, whereas the culture filtrate was able to inhibit germination up to 67.5 per cent.     

Quality evaluation of co-composted wheat straw, poultry droppings and oil seed cakes

Poultry droppings, neem cake, castor cake, jatropha cake and grass clippings were used separately as organic nitrogen additives to decrease the high C:N ratio of wheat straw. Composting was carried out aerobically in presence of fungal consortium developed by including Aspergillus awamori, Aspergillus nidulans, Trichoderma viride and Phanerochaete chrysosporium. The degraded product was characterized to assess the technical viability of organic nitrogen supplements as well as fungal consortium in improving the quality of compost and hastening the process of decomposition of high lignocellulolytic waste. Evaluation of maturity showed that mixture of wheat straw, poultry dropping and jatropha cake had the lowest C:N ratio of 10:1, the highest humic acid fraction of 3.15%, the lowest dehydrogenase activity and a germination index exceeding 80% in 60 days of decomposition. Inoculated and grass clipping amended wheat straw–poultry dropping mixture resulted in compost with highest humus content of 11.8% and C:N ratio of 13.5, humic acid fraction of 2.84% and germination index of 59.66%. Fungal consortium was effective in improving the humus content of all the composted mixtures. In some treatments, germination index could not be correlated with C:N ratio. Non edible oil seed cake supplemented substrate mixtures did not respond to fungal inoculation as far as C:N ratio was concerned.     

Production and Pathogenicity to Wheat of Pseudocercosporella herpotrichoides Conidia

Weekly estimates of numbers of Pseudocercosporella herpotrichoides conidia on naturally infected wheat straw, made from February to July 1982, showed there were most conidia (8.1 × 10⁶ per straw) in February and least (1.9 × 10⁴ per straw) at the end of June. The viability of these spores remained high throughout this period, with an average of 85 % germination after 24 h.
After removal of spores produced in the field, straws were incubated at 5, 10, 15, 20 or 25°C and subsequent sporulation assessed after 3 or 5 weeks. The optimum temperature for spore production was 5°C and very few spores were produced at 25°C. There was no difference in viability between spores produced at different temperatures.
Wheat seedlings placed amongst infected straw collected and retained spores on the upper and lower surfaces of all leaf blades and on outer leaf sheaths. Both naturally dispersed spores and spores sprayed on to plants were not removed by subsequent rainfall.
When wheat seedlings were inoculated between the coleoptile and outer leaf sheath with different numbers of P. herpotrichoides spores, lesion development was most rapid in seedlings inoculated with the greatest numbers of spores. However, after incubation for 12 weeks visible lesions were present on all plants inoculated with > c. 10 spores.     

Effectiveness of microbial pretreatment by Ceriporiopsis subvermispora on different biomass feedstocks

Different types of feedstocks, including corn stover, wheat straw, soybean straw, switchgrass, and hardwood, were tested to evaluate the effectiveness of fungal pretreatment by Ceriporiopsis subvermispora. After 18-d pretreatment, corn stover, switchgrass, and hardwood were effectively delignified by the fungus through manganese peroxidase and laccase. Correspondingly, glucose yields during enzymatic hydrolysis reached 56.50%, 37.15%, and 24.21%, respectively, which were a 2 to 3-fold increase over those of the raw materials. A further 10-30% increase in glucose yields was observed when pretreatment time extended to 35 d. In contrast, cellulose digestibility of wheat straw and soybean straw was not significantly improved by fungal pretreatment. When external carbon sources and enzyme inducers were added during fungal pretreatment of wheat straw and soybean straw, only glucose and malt extract addition improved cellulose digestibility of wheat straw. The cellulose digestibility of soybean straw was not improved.     

Nitrogen Fixation in the Phyllosphere of Tropical Plants: Occurrence of Phyllosphere Nitrogen-Fixing Micro-organisms in Eastern India and their Utility for the Growth and Nitrogen Nutrition of Host Plants

Of the 560 leaf samples belonging to 259 species of green plantsexamined more than 50 per cent of the Angiosperms and 25 percent of the Pteridophytes and Gymnosperms revealed the presenceof N₂-fixing micro-organisms in their phyllosphere. Plants particularlyremarkable in this respect are orchids and several other epiphytes,Scindapsus officinalis, Ficus and cucurbits. Most of the isolatesappear to be biotypes of Klebsiella pneumoniae. The more activestrains fixed more than 5 mg N g^–1 glucose utilized andreduced more than 100 nmol C₂H₂ mg^–1 cell d. w h^–1. The efficacy of the phyllosphere N₂-fixing isolates for N-nutritionof host plants was studied by spraying suspensions of the culturesgrown on N-free media on rice and wheat seedlings. In IR-26rice or Sonalika and Janak wheat grown on soil in wooden flatsor earthenware pots, 22 per cent of the 161 cultures studiedcaused increased height and about three-quarters of the culturesenhanced dry weight by more than 50 per cent; chlorophyll andN-contents were enhanced more than 50 per cent by about halfand two-thirds of the cultures respectively. In N-free sandculture 26 of the 50 promising strains doubled N-content, and30 doubled dry weight of the tested plants. In some cases dryweight, number of grains per panicle, and 1000 grain weightwere increased by 300, 70–83 and 126–158 per centrespectively; N-content of straw and seed was increased three-or fourfold. In several cases the beneficial effects were foundto match closely the performance of plants receiving ammoniumsulphate. Nitrogen-fixing micro-organisms, nitrogen nutrition, phyllosphere, rice, tropical plants, wheat     

Dipeptidase development in cotyledons of Cucurbita maxima during germination

The dipeptidase activity of an unpurified soluble extract of the cotyledons of Cucurbita maxima Duch. var. Hubbard remained unchanged during the first 2 days of germination and then increased at a rapid rate during the next 3 days. The dipeptidase activity of two of three lots of seeds required the presence of the embryo axis for maximal dipeptidase activity, whereas the third lot was uninfluenced by the embryo axis. This discrepancy was possibly due to genetic differences. In those seeds which required the presence of the embryo axis for maximal dipeptidase activity, the cytokinin benzyladenine could replace the embryonic axis. When the protein synthesis inhibitor cycloheximide was added to the seeds at the beginning of germination, it inhibited dipeptidase activity of the cotyledons from 26 to 55 per cent, depending of the basis of calculation, at 5 days. When the cycloheximide was added to 3-day-old seedling the inhibition of dipeptidase activity in the cotyledons was almost immediate. The relative hydrolysis of -leucylglycine and glycylglycine were compared after temperature inactivation and purification; the results showed that more than one enzyme was responsible for the dipeptidase activity. The presence of a dialysable dipeptidase inhibitor(s) was demonstrated. Relatively high dipeptidase activity was also found in the roots and shoots.