南京早椒×C.chinense种间杂交的受精和胚胎发育

对南京早椒（ＣａｐｓｉｃｕｍｆｒｕｔｅｓｃｅｎｓＬＶａｒ．ＣｏｎｏｉｄｅｓＢａｉｌｅｙ）×Ｃ．Ｃｈｉｎｅｎｓｅ种间杂交受精和胚胎发育过程的观察表明：授粉后２～６小时，花粉在柱头上萌发，８～１２小时为花粉萌发盛期，产生花粉管，开始进入柱头组织。授粉后５２～７２小时，精核进入卵细胞和中央细胞，完成双受精。原胚发育为茄型。从授粉、受精、合子分裂、指形胚、球形胚、心形胚、鱼雷形胚至成熟胚的整个发育阶段历经３２天。极核受精前靠近卵器，受精后立即分裂。胚乳发育属细胞型。杂交组受精和胚胎发育较自交组迟。     

山楂花粉及花柱生理生化特性与受精能力的关系

试验对受精能力较强的野生山楂和受精能力差的栽培山楂品种敞口、面楂、大金星的花粉和花柱部分生理生化指标进行了比较。结果表明，栽培山楂与野生山楂花粉生活力无显著差异，但栽培山楂花粉萌发率较低，花粉管生长速度较慢，其中大金星花粉25℃培养24h仍不能萌发，栽培山查花柱提取液对野生山楂和栽培山查花粉萌发都有抑制作用。栽培山楂花粉中酚类物质含量较高，其中大金星含量最高，花柱中IAA氧化酶活性明显高于野生山楂，而可溶性糖含量低于野生山楂。敞口、大金星和面楂花柱中POD同工酶分别比野生山楂多2，3，4条酶带，而花粉POD同工酶无区别。     

不同肥料运筹对夏玉米的生产效应

【研究目的】以高产夏玉米新品种鲁单9006为试验材料，研究了不同肥料运筹对夏玉米产量、籽粒品质和土壤性状的影响。【方法】大田试验结合室内分析试验比较分析了不同肥料运筹的生产效应。【结果】与施用普通化肥相比，施用包膜化学肥料特别是控释肥料在玉米增产、肥料利用效率与经济效益提高等方面的效果明显要好，并可部分地改善玉米籽粒品质和耕层土壤性状；不同肥料运筹的玉米生产效益分析结果表明：施用等养分量控释肥的经济效益显著高于普通化肥，减量控释肥施用的经济效益要优于全量控释肥，普通化肥一次施用优于分次施用。【结论】施用包膜化学肥料特别是控释肥料对夏玉米的生产效应明显好于施用普通化肥；在提高玉米产量的同时，减少肥料成本投入也是提高玉米生产效益的有效措施。     

山楂受精能力与其花粉和雌蕊生理生化特性的关系

用受精能力强的野生山楂的花粉给受精能力差的3个栽培品种‘面楂’、‘敞口’、‘大金星’授粉，并对野生山楂和栽培山楂花粉与雌蕊的部分生理生化指标进行了比较。结果表明，野生山楂的花粉能显著提高栽培山楂种子含仁率。栽培山楂与野生山楂花粉生活力无显著差异，但栽培山楂花粉萌发率较低。花粉管生长速度较慢，其中‘大金星’花粉在25℃培养24h不能萌发。栽培山楂雌蕊提取液对栽培山楂和野生山楂花粉萌发都有抑制作用。与野生山楂相比，栽培山楂花粉中类胡萝卜素、游离脯氨酸和可溶性蛋白质含量较低，酚类化合物含量和POD活性较高，其中‘大金星’花粉中类胡萝卜素和可溶性蛋白质含量最低。酚类化合物含量和POD活性最高。雌蕊中IAA氧化酶活性明显高于野生山楂，而可溶性糖含量低于野生山楂。‘敞口’、‘大金星’和‘面楂’雌蕊中POD同工酶分别比野生山楂多2、3、4条酶带，而花粉POD同工酶谱无区别。     

Growth of Nursery-grown Bamboo Inoculated with Arbuscular Mycorrhizal Fungi and Plant Growth Promoting Rhizobacteria in two Tropical Soil Typeswith and without Fertilizer Application

A nursery experiment was conducted to assess the effect of bioinoculants (Glomus aggregatum, Bacillus polymixa, Azospirillum brasilense) on seedling growth promotion of bamboo (Dendrocalamus strictus (Roxb.) Nees.) in two soil types (alfisol, vertisol) with or without fertilizer application. Bamboo seedlings were grown in the presence or absence of bioinoculants either individually or in all combinations for 180 days in field soil under tropical nursery conditions. Shoot, rhizome and root length, dry masses, nutrient concentrations and arbuscular mycorrhizal (AM) colonized root lengths were determined at harvest. Under the experimental condition tested combined inoculation of AM fungi, PSB and A. brasilense resulted in maximum growth response both under fertilized and unfertilized conditions in both soil types. Fertilizer application enhanced the efficiencies of N, P and K uptake, whereas reduced their usage efficiencies. Though soil type did not affect microbial inoculation response, fertilizer application significantly affected plant response to microbial inoculation.     

绿竹笋营养成分及笋期叶养分的施肥效应

研究施有机肥、复合肥、无机肥对绿竹笋营养成分及笋期叶片N、P、K含量的影响。结果表明 :3种肥料处理对绿竹笋N、P、K含量、粗蛋白质、粗纤维、蛋白质水解氨基酸含量有明显的促进作用 ,竹笋N和蛋白质含量以无机肥处理最高 ,P含量、氨基酸总量、必需氨基酸总量以复合肥处理最高 ,K含量、粗纤维、半需氨基酸总量以有机肥处理最高 ,但还原糖、总可溶性糖、蔗糖、淀粉含量不施肥处理明显高于施肥处理。 3种肥料处理对绿竹叶片N、P、K含量的影响在不同发笋时期表现出一定的差异性 ,发笋初期N、P、K含量施肥处理明显高于不施肥处理 ,以无机肥处理最高 ;盛期叶片N、P含量以有机肥处理最高 ,K含量以无机肥处理最高 ;末期N含量以有机肥处理最高 ,P含量以不施肥处理最高 ,K含量以无机肥处理最高 ,表现出不同肥料施肥效应的差异性。     

Variation in the amount and quality of litterfall in a Pinus sylvestris L. stand growing on a bog

The amount and nutrient content of the above-ground litterfall was followed for 9 years in an unfertilized, PKMgB and NPKMgB fertilized Scots pine stand growing on a drained ombrotrophic bog in eastern Finland. The annual litterfall on unfertilized plots was 1995 kg ha⁻¹, of which needles accounted for 74%. The effective temperature sum (threshold value + 5°C) explained 99% of the annual variation in the amount of needle litterfall when the data from one atypical year were excluded from the analysis. Nutrient concentrations were, except for Fe, higher in needle litter than in the other litterfall fractions. Nitrogen, P and K concentrations were low in autumn, and those of Ca and Mn high, possibly owing to variation in the mobility of elements during senescence. The annual litterfall input of N to the soil was 12.4 kg ha⁻¹, and the corresponding values for P and K were 0.08 kg ha⁻¹ and 1.81 kg ha⁻¹, respectively. Fertilization reduced needle litterfall in the first year after treatment, but had no effect thereafter. The amount of other litterfall fractions was not affected by fertilization in any of the 9 years of the study. Nitrogen, P, K and B concentrations increased in the needle litter after both fertilization treatments. The results indicate long-term cycling of fertilizer nutrients on the site.     

Mechanical parameters during static bending of <Emphasis Type="Italic">Pinus radiata</Emphasis> growing in a silvopastoral system I: elasticity and strength

 The effects of pasture fertilization frequency and two vertical positions in the stem on elasticity and strength parameters during static bending (modulus of elasticity, stress at proportional limit, modulus of rupture) of Pinus radiata wood growing in a silvopastoral system were evaluated. Twenty-seven trees were selected randomly from three silvopastoral trials established at Tanumé Experimental Center (34°9′–34°15′ S; 72°53′–72°59′ W). The results indicated that pasture fertilization frequency had no significant effect on the physical and mechanical parameters evaluated. However, the vertical position in the stem did have a significant effect on stress at the proportional limit and on the modulus of rupture due to different average values for the annual ring width and nominal density found in the specimens obtained from logs at two different heights of the stem. Received: February 20, 2002 / Accepted: June 5, 2002 Acknowledgments The authors thank the following institutions and people for their support: CONAF, VI Region; Dr. Rolando Rodríguez, CONAF VIII Region; Cesar Cabrera, Forestry Engineer, CONAF VI Region; Osvaldo Herrera, Director of Experimental Center “Tanumé”; Dr. Manuel Sánchez, Faculty of Forestry Sciences, University of Concepción; Dr. Glenn Hofmann, Faculty of Physics and Mathematics, University of Concepción; Alex Opazo, M.Sc.(C), Faculty of Forestry Sciences, University of Concepción; Staff of Experimental Center “Tanumé”. Correspondence to:M.H.R. Vidal     

水稻免耕栽培关键技术研究

对免耕水稻的松土、除草、施肥、移抛栽等关键技术进行了研究,结果表明:施用免深耕土壤调理剂能降低土壤容重、增加土壤阳离子交换量;不同种类的除草剂对不同类型的杂草的除草效果不同,应根据杂草的类型选择合适的除草剂或几种除草剂综合施用;应采用小量多餐、化肥后移、根外补肥的施肥技术;应采用小苗带土移栽或抛栽的移栽技术。     

黄淮海地区冬小麦施肥技术参数与指标体系的研究

通过对小麦3414肥效试验结果的分析,计算出小麦单位产量养分吸收量、土壤养分利用系数、肥料利用率等施肥参数,在此基础上对土壤速效养分含量与肥料利用率的相关关系进行了初步探讨,利用3414试验得到最佳施肥量,结合土壤测试值与相对产量的回归关系,建立基于土壤常规测试条件下的土壤养分丰缺指标与施肥数量指标体系。