Response of apple trees to boron fertilization under conditions of low soil boron availability

The aim of the study was to examine the effect of boron (B) fertilization on the vegetative and the reproductive responses of apple (Malus domestica Borkh.) trees grown at low soil B availability. The experiment was carried out in 2005 under a greenhouse on 5-year-old ‘Jonagold’ apple trees/M.9 EMLA planted singly in 50-L containers filled with a sandy loam soil with hot water-soluble B concentration of 0.32 mg kg⁻¹. The trees were fertilized with B as foliar or soil application. Foliar B sprays were applied at the stage of pink bud, beginning of flowering, petal fall, and 10 days after flowering, at a solution concentration of 0.03%. Soil B fertilization was done at the bud break stage at a rate of 2 g per tree (27 mg B kg⁻¹ soil). The trees untreated with B served as the control. The results showed that soil B fertilization improved root development and tree vigor. Leaves of trees supplied with B to the soil had higher B concentration and chlorophyll, net photosynthetic rate, stomatal conductance, and activity of catalase and glutathione reductase than those of the control plants. Boron fertilization, regardless of application mode, increased fruit yield; the efficiency of foliar B sprays was higher than soil B application. Apple fruits of trees fertilized with B to the soil were bigger, more colored, richer in B, and had higher soluble solids concentration, and titratable acidity compared to those of the control trees.     

Genetic control of growth and form in early-age tests of Casuarina equisetifolia in Andhra Pradesh, India

Early results from three test plantings of Casuarina equisetifolia spp. equisetifolia are reported: a clonal test of 40 locally selected clones, a progeny test of 16 wind-pollinated families of local origin, and a family-in-provenance test of 100 wind-pollinated families which is part of an international provenance trial. All tests were planted in 1996 at the Regional Forest Research Centre, Rajahmundry, Andhra Pradesh, India. Height, stem straightness and axis persistence were measured in the family tests at 6 and 12 months of age. The height of the clonal test was measured at 12 months of age. Heritability estimates obtained were ca. 0.3, 0.2 and 0.1 for height, stem straightness and axis persistence, respectively. Heritability estimates for height were reasonably consistent across the three tests; however, estimates for stem straightness and axis persistence were generally higher in the small test of locally selected families. Height and the other two traits are most probably either weakly correlated or uncorrelated, while stem straightness and axis persistence are positively correlated. Provenances spread across the range of natural- and land-race populations tested demonstrated good growth potential at Rajahmundry. However, natural provenances from Malaysia and Thailand generally showed superior growth, while the land-race populations often demonstrated superior stem straightness. Based on these results some aspects of a breeding strategy are outlined: (a) the establishment of three unrelated sublines; (b) an initial clonal test of all parents; and (c) wind-pollinated mating within clonal breeding orchards.     

Patterns of forest use and endemism in resident bird communities of north-central Michoacán, Mexico

We compared breeding avian communities among 11 habitat types in north-central Michoacán, Mexico, to determine patterns of forest use by endemic and nonendemic resident species. Point counts of birds and vegetation measurements were conducted at 124 sampling localities from May through July, in 1994 and 1995. Six native forest types sampled were pine, pine–oak, oak–pine, oak, fir, and cloud forests; three habitat types were plantations of Eucalyptus, pine, and mixed species; and the remaining two habitats were shrublands and pastures. Pastures had lower bird-species richness and abundance than pine, oak–pine, and mixed-species plantations. Pine forests had greater bird abundance and species richness than oak forests and shrublands. Species richness and abundance of endemics were greatest in fir forests, followed by cloud forests. Bird abundance and richness significantly increased with greater tree-layer complexity, although sites with intermediate tree complexity also supported high abundances. When detrended correspondence-analysis scores were plotted for each site, bird species composition did not differ substantially among the four native oak-and-pine forest types, but cloud and fir forests, Eucalyptus plantations, and mixed-species plantations formed relatively distinct groups. Plantations supported a mixture of species found in native forests, shrublands, and pastures. Pastures and shrublands shared many species in common, varied greatly among sites in bird-species composition, and contained more species specific to these habitats than did forest types.     

硼在土壤中的吸附-解吸及其对植物吸收硼的影响

本文对湖北省几种主要旱地土壤进行了硼的吸附－解吸实验,同时对这些土壤上油菜幼苗吸收硼进行了试验,并用Ｆｒｅｕｎｄｌｉｃｈ和Ｌａｎｇｍｕｉｒ等温吸附方程对实验结果进行了拟合。从中发现,一些土壤硼的解吸存在着明显的滞后解吸现象,这种现象可用滞后系数来定性描述。     

磷素对高硼土壤小麦生长的影响

为减轻高硼(B)对小麦的毒害作用,研究了不同土壤B浓度下磷(P)素对小麦生长的影响。结果表明,增施P素能减轻小麦B毒害症状,小麦平均黄叶率由9.95%降至7.60%;促进小麦生长,B浓度为50mg/kg时,小麦根系和地上部分生物量分别增加44.9%和11.72%,30cm以下土层根系平均增加2.1%,促进了小麦对深层养分和水分的利用。     

施用硼肥对杏树落花落果的影响

Effect of boron on falling of prunes (Prunus mune,Sieb,et Zucc) was studied by applying 50g borate per tree into soil on december 15,1993(soil-B) and spraying leaves leves evenly twice with 1.5g kg^-1 borate solution on March 1 and 8,1994(spray-B) on the soil with 0.28mg kg^-1 rapidly available B.Compared with no borate treatment (CK),B concentrations of leaves,short branches and flowers were higher and the percentage of flower and fruit drop was lower in the treatments of soil-B and spray-B.B fertilizer increased B concentrations in flowers,leaves and short branches,promoted pollen germination,reduced the percentage of fall of flowers and fruits of prunes,increased the percentage of fertile fruits,and thus increased yields of prunes by 46% and 34.3% in the treatments of soil-B and spray-B,respectively.It could be inferred preliminarily that if B concentration of leaves was lower than 35 mgkg^-1,the prunes should be fertilized with B.The measured leaves should be picked from branches(3-10cm in legnth)germinating from the central section of a tree crown during the last ten days of May to the early days of June.     

培养基质,赤霉素和硼对蕨菜孢子萌发成苗影响的研究

为了提高蕨菜孢子人工培养成苗效率,对４ 种培养基质和赤霉素（ＧＡ３）、硼３ 种使用水平的孢子萌发成苗效果进行了研究。结果表明,森林土、琼脂和蛭石间原叶体数无差异,但成苗率间差异显著;森林土成苗率最高,达到４２．８６％ ;砂基上孢子虽能萌发产生片状体,但不能发育到性器官形成期;赤霉素对孢子萌发生长具有显著的促进作用,在含有０．１５×１０－ ７ ｇ／Ｌ赤霉素培养基上成苗率较高;硼可提高配子体受精成苗,并以０．０５％ 硼酸处理效果最好;赤霉素与硼有显著的互作效应,含有０．１５×１０－ ７ ｇ／Ｌ赤霉素培养基上生长的原叶体,在性器官形成期喷施０．０５％ 硼酸,成苗率高达５１．６０％ 。     

一种测定水合氧化物吸附硼热效应的新方法

为了解决２种溶液在混合前温度不易相等的问题而设计的双温度计法,可以快速测定２种溶液混合前后温度差值,并将这一新方法用于衡量锰、铝、铁水合氧化物在吸附溶液硼时所产生的热效应。结果表明：锰、铝、铁的水合氧化物对硼的吸附均有不同程度的热效应。供试样品与硼发生吸附反应所引起的热效应造成温度随时间变化的情况与通常的雷诺曲线相同,而水合氧化物悬浮液以及吸附质溶液的稀释与吸附反应相比较。其热效应小得多。使用这种     

硼中毒对固始鸡生长性能及胸腺发育的影响

120只 1日龄固始鸡随机分为 2组, 试验组在饮水中添加 400mg·L-1硼。每周每组取鸡 10只, 颈静脉放血致死,取胸腺, 称重, 制作石蜡切片, 光镜观察。实验结果表明: (1 ) 试验组胸腺重及胸腺 /体重比显著低于同周龄对照组(P<0 05), 3、5、6周龄胸腺重及 1、2、3、5周龄胸腺 /体重比极显著低于对照组 (P<0 01); (2) 试验组 1、2周龄鸡胸腺明显萎缩, 间质显著增多, 实质急剧退化, 胸腺细胞急剧减少或空竭, 胸腺小体增多、增大; (3) 3周龄起, 试验组大多鸡胸腺发育呈恢复状态, 6周龄, 胸腺组织结构基本恢复。以上结果提示, 添加 400mg·L-1硼的饮水对固始鸡的生长与胸腺的发育, 尤其是胸腺早期发育, 有明显抑制和毒性作用。     

硼酸对萝卜成花生理代谢与亲和性的影响

采用不同浓度的硼酸分别喷洒萝卜叶片和花蕾,调查硼对自交不亲和萝卜成花生理代谢与亲和性的影响。结果显示:叶面喷施硼酸对萝卜生理代谢有显著影响:硼酸浓度越高,抽薹前期萝卜叶片的可溶性糖含量越高,但是从抽薹开始,硼效应已经不明显;硼处理下的叶绿素含量始终高于对照;0.6%硼酸处理下萝卜POD活性最高;从现蕾开始,硼处理下的脯氨酸含量始终高于对照。蕾期喷施硼酸可以在一定程度上促进花粉管伸长,提高亲和指数,尤以双核期喷施0.4%硼酸的效果最好,其亲和指数达到3.08。总体看来,在萝卜成花过程中,硼酸处理无论是对萝卜成花过程的生理代谢还是亲和性都存在显著影响。