桐粮间作林带的配置方式与农作物产量关系的研究

以桐粮间作为例,研究了林带的不同配置结构、林带冠覆盖率及小麦产量之间的关系。结果表明,林带距（Ｘｄ）、小麦相对产量（Ｙ）及间作年（Ａ）之间的关系为：Ｙ＝９０．３２９０－１．９９８２Ａ＋１．１９２４Ｘｄ－０．３３４９Ａ＾２＋０．２９１０ＡＸｄ－０．００３２ＡＸｄ＾２;林带冠覆盖率（Ｘｃ）与小麦相对产量（Ｙ）之间的关系为：Ｙ＝－０．０４６Ｘｃ＾２＋１．１５３９Ｘｃ＋９８．１７３（Ｘｃ≤２８％）,Ｙ＝ｅ     

果农复合系统根系分布格局与生长动态研究

对苹果、小麦复合系统根系分布格局生长动态的研究表明：（１）４年生苹果根系垂直分布这１００ｃｍ,其主要分布在２０～６０ｃｍ,可占总根量的８０％以上;小麦根系垂直分布可达８０ｃｍ,０～１０ｃｍ占５５．２％,与苹果根系在空间尺度上不复重叠;而不间作时,苹果根系有上浮趋势。（２）苹果幼树根系的水平分布达２５０ｃｍ,大多在０～１００ｃｍ范围,占４２．４％;间作时两边各留１００ｃｍ的保护行,基本不影响小麦生长     

不同质地土壤的水热状况及其对冬小麦产量形成的影响

对豫东平原３种质地土壤的水热状况和冬小麦籽粒生长特征进行了研究．结果表明,冬小麦籽粒生长阶段,粘壤土５ｃｍ处的日平均温度最低,为１８．３℃,砂壤土最高,为１９．５℃,中壤居中,为１９．１℃．３种土壤的含水量大小顺序为粘壤＞中壤＞砂壤,粘壤土上小麦籽粒灌浆时间最长,千粒重最高,分别为３８ｄ和４５．５ｇ,砂壤土小麦籽粒灌浆时间最短,千粒重最低,分别为３３ｄ和４２．４ｇ,中壤土小麦２项指标居中,分别为３６ｄ和４３．１ｇ．高产栽培条件下,粘壤土冬小麦产量最高,为８２５３ｋｇ·ｈｍ－２,中壤次之,为７９８０ｋｇ·ｈｍ－２,砂壤最低,为７６１７ｋｇ·ｈｍ－２     

小麦-大豆间作中小麦对大豆磷吸收的促进作用

采用塑料膜,２０μｍ尼龙网分司以及不分隔两种俄根系的盆栽装置研究了小麦,大豆间作种间磷吸收的促进作用。结果表明,两种作物根系用尼龙网分隔后,即种间磷竞争作用基本消除后,小麦对大豆磷吸收具有明显的促进和,表现为大豆生物学产量明显提高,是塑料膜分隔的２．５倍,是无分隔４．６倍,尼龙网分隔,大豆分隔,大豆的根系活力高于塑料膜分隔４５．２％,达显著水平,此外,尼龙网分隔形成小麦根面,大豆的根系呈偏向小麦根     

黄土高原塬区旱地长期施肥对小麦产量的影响

以18年长期肥料定位试验为背景,研究了长期施肥条件下小麦的增产效应18年单施氮肥平均增产418．1kg·hm^-2,增产率达28．4％,其中干旱年减产率为13．9％,常态年、丰水年增产率达30．3％、58．9％;单施磷肥平均减产率为9．3％,干旱年增产率达6．5％,常态年、丰水年减产率为15．4％、10．0％;有机肥平均增产率达82．8％;NP、PM、NM、NPM平均增产率分别达127．8％、118．9％、144．4％,169．3％,不同降水年型施肥对小麦的产量结构影响不同,普遍表现为干旱年成穗数、穗粒数、千粒重减少,丰水年增加,不同降水年型穗粒数、成穗数、千粒重的变化是不同施肥处理对小麦产量结构的调控措施。     

国产重组酵母乙型肝炎疫苗接种小学生的3年免疫效果观察

本文报告对２５８ 名小学生应用０、１、６ 月程序,接种２ 批国产酵母疫苗（５ μｇ／０．５ ｍ ｌ）,１ 批Ａｍ ｇｅｎ 酵母疫苗（１０ μｇ／ｍ ｌ）,１ 批Ｍ ＳＤ 酵母疫苗（５ μｇ／０．５ ｍ ｌ）的小学生免后３ 年（（Ｔ３６）效果观察。结果表明,Ｔ３６ 时抗体 ＧＭＴ（几何平均滴度）,Ａｍ ｇｅｎ 疫苗组（１４５．７５）显著高于 ２ 批国产疫苗（９２．１１、８３．５２）和Ｍ．Ｓ．Ｄ 苗组（７４．６２）,抗体ＧＭＴ 峰值显著低于Ａｍ ｇｅｎ 和Ｍ ．Ｓ．Ｄ 苗的２ 批国产酵母疫苗,与Ｍ．Ｓ．Ｄ 苗抗体ＧＭＴ 水平无显著差异（Ｐ＞ ０．０５）。抗体阳转率间各疫苗组均无显著差异（９３．１０％ ～７４．１４％ ）。本次随访结果表明,采用０,１,６ 免疫程序,国产酵母疫苗免后３ 年的抗体阳转率和抗体ＧＭＴ水平不低于进口同类酵母疫苗的水平。     

硬粒小麦单倍体原生质体培养及植株再生

由硬粒小麦（Ｔｒｉｔｉｃｕｍ ｄｕｒｕｍ Ｄｅｓｆ．）×玉米（Ｚｅａ ｍａｙｓＬ．）建立的单倍性胚性愈伤组织,在继代培养４ 个月后置于含２．０ ｍ ｇ／Ｌ２,４－Ｄ、３％ 蔗糖、２００ ｍ ｇ／Ｌ水解酪蛋白、１４６ ｍ ｇ／Ｌ谷氨酰胺和３００ ｍ ｇ／Ｌ天冬氨酸的ＭＳ液体培养基中进行悬浮培养,４ 个月后形成了生长迅速、由大小不同（０．５ ～５ ｍ ｍ ）的愈伤组织块组成的愈伤组织悬浮系。酶解试验表明,２．０％ 纤维素酶ＲＳ和０．５％ 的离析酶效果最好,而液体悬浮培养物和固体培养的愈伤组织（在酶解时用锋利的解剖刀片切成１ ｍ ｍ 左右的小块）都能释放出大量原生质体,但悬浮培养物释放出的原生质体状态较好,胞质更浓厚,用ＫＭ８ｐ 培养基以琼脂糖包埋培养方式培养时分裂频率可达５％ 左右。由原生质体再生的小愈伤组织经增殖、筛选后可获得胚性愈伤组织,将其转移至分化培养基Ⅰ（０．２ ｍ ｇ／Ｌ ２,４－Ｄ、１．０ ｍ ｇ／Ｌ ＢＡＰ、０．１ ｍ ｇ／ＬＮＡＡ、３％ 蔗糖、２００ ｍ ｇ／Ｌ 水解酪蛋白、１４６ ｍ ｇ／Ｌ谷氨酰胺和３００ ｍ ｇ／Ｌ天冬氨酸的ＭＳ固体培养基）和Ⅱ（不含２,４－Ｄ,其它成分同Ⅰ）上进行分步分化培养可再生出完整植株,分化频率约为２０％     

茶果（林）复合园的光特征研究

茶果（林）复合园上层林冠透光率落叶树种比常绿树种高２～１５％,春季可高出３０％左右,透光率维持大于５５％水平对茶叶产量影响不显著．林冠下的散射量１２～１４时已超过２．９Ｊ·ｃｍ－２·ｍｉｎ－１的茶树光饱和点水平落叶树下散射光量占总辐射量春季达６５～８０％,夏、秋季４５～６０％茶树树冠面反射光量占总辐射量比例小,晴天约为５～８％,年变辐为５～１０％,日变幅以１０～１５时最高,夏、秋季高达０．２～０．４Ｊ·ｃｍ－２·ｍｉｎ－１茶树树冠透射光量在５００～２０００ｌＸ,日变化以１６～１７时透射率最高约１５～２０％,茶树吸收光占总量８０～８５％     

电场对油葵种子苗期干旱胁迫后生长的影响

用不同电场强度处理油葵种子,在田间和实验室测定电场处理种子对苗期干旱胁迫后生长的影响。研究结果表明,种子经电场处理,可明显提高油葵生长的抗旱能力。在０．５ｋＶ／ｃｍ－６．０ｋＶ／ｃｍ场强范围内,不同电场强度对其生长的影响程序不同。与对照组相比,田间出苗率提高４．１１％￣２８．０％,根冠比提高６．６０％￣３８．７％,植株萎蔫程度降低５．０％￣９５％,产量提高３．４０％￣１７．９％,含油率提高１．０３     

大肠癌及癌旁粘膜中胃泌素、生长抑素细胞的免疫细胞化学研究

本文对１７例大肠癌病人癌组织及癌旁粘膜中的胃泌素细胞和ＳＳ细胞进行免疫细胞化学观察（ＰＡＰ）。结果显示：在癌及癌旁粘膜中来见胃泌素细胞;癌细胞中均未见ＳＳ细胞;癌旁粘膜中ＳＳ细胞的形态、位置近于正常。距癌灶０～２ｃｍ粘膜ＳＳ细胞数和总阳性强度显著高于２～６ｃｍ和４～６ｃｍ粘膜（Ｐ＜０．０１）。０～２ｃｍ粘膜中ＳＳ细胞数和总阳性强度与粘膜上皮细胞异型增生程度呈显著负相关（前者Ｐ＜０．０１;后者Ｐ＜０．０５）。Ｄｕｋｅｓ’ＣＤ期者０～２ｃｍ和２～４ｃｍ粘膜中细胞平均阳性强度均显著低于ＡＢ期患者（前者Ｐ＜０．０５,后者Ｐ＜０．０１）。距癌０～２ｃｍ粘膜ＳＳ细胞增多和总阳性强度增高可能是机体发生在病变部位的胃肠内分泌防御反应的细胞学基础,并受到粘膜上皮异型增生程度的影响。晚期０～４ｃｍ粘膜ＳＳ细胞分泌ＳＳ减少是机体胃肠内分泌功能衰退的表现。     

橡胶树大筒苗培育方法VII.遮阴率的筛选

为了解不同遮阴环境下橡胶树(Heveabrasiliensis)大筒苗的生长及光合特性,明确大筒苗生长的适宜光照环境,以小苗芽接苗和组培苗为胚苗的橡胶树大筒苗为材料,设置5个遮阴处理：CK (全光照),S60、S70、S80和S90 (分别为60%、70%、80%、90%遮阴率),观测其出圃时的生长指标和光合参数变化情况。结果表明,不同遮阴率对橡胶树大筒苗的生长、光合参数及出圃时顶蓬叶的叶面积和叶绿素相对含量均有极显著影响,且2种胚苗间差异显著。大筒苗的壮苗指数随遮阴率的增加呈现先增后降的趋势;与全光照相比,遮阴显著影响大筒苗的出圃率,但对定植成活率的影响较小;胚苗类型与遮阴处理的交互作用明显。全光照和过度遮阴(S90)均会明显抑制大筒苗的生长,不同胚苗的大筒苗最适遮阴率不同,小苗芽接苗大筒苗在S60、组培大筒苗在S80下的生长表现最好。因此,橡胶树大筒苗培育时应根据不同的胚苗类型选择适宜的遮阴措施。     

不同光照强度下半夏化学成分含量的比较研究

利用遮荫网对卵叶型半夏（Pinellia ternata（Thunb.）Breit.）进行遮荫,秋季倒苗后,测定其化学成分含量,以研究光强对半夏化学成分含量的影响。结果显示：全光照下半夏的生物碱、鸟苷和蛋白质含量较高,55%遮荫处理半夏的块茎增重幅度较大,80%遮荫处理的还原糖和可溶性糖含量较高。不同光照强度下,半夏化学成分含量有显著的差异,全光照处理有利于半夏生物碱、鸟苷和蛋白质的积累,80%遮荫处理有利于其还原糖和可溶性糖的积累,55%遮荫处理有利于半夏的生长,但其化学成分含量低于全光照处理。     

遮荫对风箱果幼苗光合能力和碳水化合物积累的影响

以1年生风箱果幼苗为材料,采用人工遮荫方式设置CK （全光）、轻度遮荫L1（60%全光）和重度遮荫L2（20%全光）3种光环境,测定不同光环境下风箱果幼苗的光合特性、光合色素含量、非结构性碳水化合物（NSC）积累等,分析风箱果幼苗对不同遮荫环境的适应性。结果表明：风箱果属于阳生树种,对光环境的变化非常敏感;遮荫显著降低了表观量子效率（AQY）、最大净光合速率（P_max）、暗呼吸速率（R_d）、光补偿点（LCP）、光饱和点（LSP）和类胡萝卜素含量（Car）（P<0.05）,显著提高了叶绿素a （Chla）、叶绿素b （Chlb）、总叶绿素（Chl）含量和叶绿素/类胡萝卜素（P<0.05）;遮荫显著减少了根、茎、叶中NSC含量（P<0.05）,尤其是L2时,分别比CK减少了52.5%、44.9%和43.9%。综上所述,风箱果幼苗对于遮荫环境的适应和调节能力较差,生产实践中应栽植在阳光充足的环境中。     

Effects of tree competition on corn and soybean photosynthesis, growth, and yield in a temperate tree-based agroforestry intercropping system in southern Ontario, Canada

In 1987, the University of Guelph established a large tree-based intercropping system on 30 ha of prime agricultural land in southern Ontario, Canada. The purpose was to investigate various aspects of intercropping trees with prime agricultural crops. In this study, objectives were to investigate tree competitive effects (i.e., shading and competition for soil moisture) on under-story crop net assimilation (NA), growth, and yield. The effects of tree competition on corn (C4 plant) and soybean (C3 plant) photosynthesis and productivity in the intercropped system were studied during the 1997 and 1998 growing seasons. Corn and soybeans were intercropped with hybrid poplar (clone-DN-177) and silver maple (Acer sacharrinum) at a within-row spacing of 6 m and between-row spacing of 12.5 or 15 m. Trees were absent from control rows. Tree rows were oriented approximately north and south. Twelve crop locations were sampled around each tree. These were at 2 and 6 m east and west of the tree, located along a primary axis running through the tree trunk and perpendicular to the tree row, and at 2 m north and south of each location along the primary axis. Net assimilation and plant water deficit measurements were made three times daily (morning, noon, afternoon) on sampling days in July. Generally, tree competition significantly reduced photosynthetic radiation (PAR), net assimilation (NA), and growth and yield of individual soybean or corn plants growing nearer (2 m) to tree rows in both years and soil moisture in 1998. NA was highly correlated with growth and yield of both crops. These correlations were higher for corn than soybeans in both years, with corn, rather than soybeans being more adversely impacted by tree shading. In 1997, poplar, rather than maple, had the greatest competitive effect on NA. In 1997, the lowest plant water deficits, for soybeans and for corn, were observed for the maple treatment. Nonetheless, in both years, daily plant water deficits were non-significantly and poorly correlated with NA and growth and yield of both crops. However, soil moisture (5 and 15 cm depth) was significantly correlated with soybeans yield in 1998. Possible remediation strategies are discussed to reduce tree competitive interactions on agricultural crops.     

Quantifying street tree regulating ecosystem services using Google Street View

The urban heat island is a particular challenge for tropical cities, which receive year-round high inputs of solar radiation. Plants can help mitigate elevated urban temperatures by providing shade and increasing evaporative cooling, although the resulting increase in humidity may negatively affect thermal comfort. Street trees offer particular potential for cooling urban microclimates, as well as providing other ecosystem services, because they can be integrated within dense urban street networks. However, we have little quantitative information about the role of street trees in providing regulating ecosystem services in tropical cities. In this study, we analysed hemispherical photographs extracted from Google Street View to quantify the proportion of green canopy coverage at 50 m intervals across more than 80% of Singapore’s road network. Canopy coverage data were then used to estimate the proportion of annual radiation that would be blocked from reaching ground level by the canopy. Across all locations, a median of 13% of the annual diffuse and direct solar radiation was shaded, and over 70% of this shading effect was due to the tree canopy. There was significant variation between different urban landuse types, with trees providing more shade in parks and low-density low-rise areas than in industrial and higher-density residential areas. Mapping the provision of street tree ecosystem services could help to prioritise areas for new planting by identifying streets or street sections with low shading. The approach developed in this article could be readily applied to quantify the proportion of canopy coverage and proportion of solar radiation shaded across other tropical cities. The method may also be applicable in temperate cities if Google Street View photographs were collected during the growing season.     

遮荫对山麦冬生长特性和生物量分配的影响

研究了不同遮荫水平（遮光率分别为:对照0%、 20%、50%、70%～75%、80%～85%、92.5%）对山麦冬生长以及生物量分配特性的影响。结果表明,随着遮荫程度的加重,山麦冬的生物量增量表出现先上升后下降的趋势,在遮荫50%水平下生物量增量达到最高;随光强减弱同化物分配发生改变,叶重比增加,根重比和根冠比下降。此外,遮荫还提高了植株的含水量和冠径。我们还观察到强光环境和深度遮荫均不利于花序、分蘖和块根的形成。因此,我们认为山麦冬作为耐荫植物对光环境具有一定的适应能力,强光或严重遮荫均不利于其正常生长发育。     

Salinity tolerance of 'Valencia' orange trees on rootstocks with contrasting salt tolerance is not improved by moderate shade

The effects of shading in combination with salinity treatments were studied in citrus trees on two rootstocks with contrasting salt tolerance to determine if shading could reduce the negative effects of salinity stress. Well-nourished 2-year-old 'Valencia' orange trees grafted on Cleopatra mandarin (Cleo, relatively salt tolerant) or Carrizo citrange (Carr, relatively salt sensitive), were grown either under a 50% shade cloth or left unshaded in full sunlight. Half the trees received no salinity treatment and half were salinized with 50 mM Cl- during two 9 week salinity periods in the spring and autumn interrupted by an 11 week rainy period. The shade treatment reduced midday leaf temperature and leaf-to-air vapour pressure deficit regardless of salinity treatments. In non-salinized trees, shade increased midday CO2 assimilation rate (A(CO2)) and stomatal conductance, but had no effect on leaf transpiration (E(lf)). Shade also increased leaf chlorophyll and photosynthetic water use efficiency (A(CO2)/E(lf)) in leaves on both rootstocks and increased total plant dry weight in Cleo. The salinity treatment reduced leaf growth and leaf gas exchange parameters. Shade decreased Cl- concentrations in leaves of salinized Carr trees, but had no effect on leaf or root Cl- of trees on Cleo. There were no significant differences in leaf gas exchange parameters of shaded and unshaded salinized plants but the growth reduction from salinity stress was actually greater for shaded than for unshaded trees. Shaded trees on both rootstocks had higher leaf Na+ than unshaded trees after the first salinity period, and this shade-induced elevated leaf Na+ persisted after the second salinity period in trees on Carr. Thus, shading did not alleviate the negative effects of salinity on growth and Na+ accumulation.     

Selection of shade trees in forest restoration plantings should not be based on crown tree architecture alone

The planting of tree seedlings is a common restoration technique in the tropics, and using large‐crowned, fast‐growing shade species is recommended to suppress invasive grasses and accelerate forest succession. We analyzed the effectiveness of shade species in shading the forest floor during the rainy and dry seasons at young forest restoration sites, whether shade changes according to site for a given species, and whether crown architecture can predict the shade level. We measured the photosynthetically active radiation (PAR) intercepted by the tree crowns of 14 species in two 3‐year‐old restoration plantings. The ability to predict shade based on crown architecture traits was evaluated using multiple linear regressions. The interception of PAR varied according to species, site, and season for seven species and was generally higher during the rainy season. Low values of tree and first branch height and high values of trunk diameter and mean area of a leaf predicted greater light interception. For the dry season, the ability to predict PAR interception was weaker than that for the rainy season and affected by a shorter tree height and a greater crown area. The crown architecture of shade species did not completely predict their shading ability, and the preselection of shade species for forest restoration purposes based only on crown architecture traits is not effective. Therefore, it is important to consider other factors, such as how long trees retain their leaves throughout the year and the soil and management conditions of the sites undergoing restoration, during the selection of species.     

麦套春棉光照强度动态变化的研究

麦套春棉光照强度动态变化的研究孙本普,张宝民,王勇,李秀云史维泽（山东省滨州地区农业科学研究所,２５６６１５）（山东省滨州地区农业局,２５６６１８）ＶａｒｉａｔｉｏｎｓｏｆＬｉｇｈｔＩｎｔｅｎｓｉｔｙＵｎｄｅｒＩｎｔｅｒｐｌａｎｔｉｎｇｏｆＳｐｒｉｎ...     

日本落叶松林冠层光生态场研究

从生态场理论出发 ,运用邻体干扰模型和遮光影响的方法 ,研究了日本落叶松林冠层光生态场 .根据不同生长级林木之间遮光影响 ,编制了林木遮光系数表 .提出了不同生长级林木间遮光模型 .结果表明 ,7∶0 0～ 1 7∶0 0日本落叶松单冠连续投影是 1个以东西为长轴、南北为短轴的近椭圆形 ;林分内每株树木受到的遮光强度等于近椭圆范围内其它林木对其的遮光和 ;林木受到的遮光强度愈大 ,其光生态效应愈强 ,生长发育愈差 .