尾叶桉茎段再生系统的建立

本文以尾叶桉(Eucalypt urophylla)U6的无菌苗茎段为材料,选用MS培养基为基本培养基,研究不同IAA浓度对尾叶桉茎段愈伤组织诱导,不同IAA、6-BA浓度对尾叶桉茎段愈伤组织诱导芽、生根的影响。结果表明,当外植体的接种数一样,IAA的浓度为20.0mg/L时,愈伤组织诱导率达到最高,为95%,且此浓度下,出芽率、生根率最高,分别达43.3%和100%,而添加0.5mg/L6-BA则会抑制芽的再生、不能产生根。因此最适合诱导尾叶桉愈伤组织、再生芽和再生根的培养体系是MS+20.0mg/L IAA+30g/L蔗糖+8g/L琼脂。该再生系统的建立将为转基因技术改良桉树性状提供前提条件。     

Storage and Remobilization of Soluble Carbohydrates after Heading in Different Plant Parts of a Winter Wheat Cultivar

Abstract

Several types of water soluble carbohydrates (WSG) were traced into plant parts of a winter wheat (Triticum aestivum L.) cultivar from heading to physiological maturity. Field grown plants were harvested at intervals of a few days and divided into grain, chaff, leaf blades, leaf sheaths, rachis + peduncle and culm internodes. Leaf blades and sheath showed the peak of WSC contents at about anthesis. Culm internodes accumulated fructan and sucrose during the early grain-filling phase, from a week after anthesis until the milk-ripe stage, then remobilized them during late and final grain filling phases, from the milk-ripe stage until maturity. The amount of sucrose known as short-term storage WSC was higher than fructan known as long-term storage WSC in each internode throughout the grain-filling phase. Chaff showed a large amount of fructan and fructose before anthesis, although it did very little sucrose. A pattern of sucrose accumulation in chaff was very different from that of fructan, unlike the other parts. These patterns of changes in WSC contents in plant organs roughly corresponded with four grain-filling phases, the initial, early, late and final phases.     

大豆茎生长习性类型鉴别方法研究

为找到清楚、简便、准确地鉴别大豆茎生长习性类型的方法,于1988-1997年分别在南京和石家庄,研究了来自不同地区的共1536份品种和6个不同杂交组合F1、F2、F3Bernard标准的茎生长习性类型及有关的11个性状,从中选出有无顶花序(ETIMS)和上部节数相对值(RVNN)作为划分茎生长习性类型的成分性状.划分标准为:(1)有限型,有顶花序,RVNN＜0.2(夏播)或RVNN＜0.25(春播);(2)亚有限型,有顶花序,RVNN≥0.2(夏播)或RVNN≥0.25(春播);(3)无限型,无顶花序,RVNN≥0.2(夏播)或RVNN≥0.25(春播).用该法划分的结果与用Bernard标准划分的结果有很高的一致性,故在田间调查时可以用成分性状法代替Bernard方法.该法鉴定结果明确、稳定,方法简便易行,可在R3～R7期间于田间一次确定.     

Interspecific hybridization inBrassica juncea × Brassica hirta using embryo rescue

Summary Interspecific hybrids have been obtained in an otherwise incompatible cross betweenBrassica juncea × Brassica hirta through the in vitro culture of hybrid ovules and ovaries. The best response was observed from ovules and ovaries cultured 10–15 and 5–7 days after pollination respectively on a basal medium supplemented with indoleacetic acid, kinetin and casein hydrolysate. In some cases the basal cut end of the ovaries proliferated to form callus and shoots. The in vitro-derived hybrid seeds varied in their colour, size and shape, and the F₁ plants in the field showed a large diversity in their morphological traits. The hybrids were sterile, and had an intermediate number of chromosomes (2n=30).     

茎瘤芥(榨菜)数量性状遗传差异研究

对23份茎瘤芥品种资源的15个数量性状进行了主成分分析和聚类分析。结果表明:前5个主成分对变异的贡献率达85.32%,并筛选出6份综合性状表现优良的品种资源。23份品种资源被分为五类,配制组合宜在类间(D2>257.9)选择亲本。遗传差异的大小与品种的地理分布和熟性无直接联系。     

Nucleus substitution of Brassica japonica Sieb. with Raphanus sativus L. and its resultant chlorophyll deficiency

Summary Nucleus substitution of Brassica japonica (2n=20) with Raphanus sativus (2n=18) was carried out by means of repeated backcrossing of Brassicoraphavus (2n=37) to R. sativus as a pollen donor. In the course of nucleus substitution, chlorophyll deficiency appeared. Plants with more than 28 chromosomes, like their parents, had green leaves and those with 24 to 26 chromosomes had yellowish green ones. Almost all plants with 18 to 23 chromosomes showed yellow or whitish yellow. The R. sativus with B. japonica cytoplasm (2n=18) was obtained after four successive backerosses. The completely substituted R. sativus showed the same fertility as the true R. sativus used as a recurrent parent. It is assumed that the chlorophyll deficiency is caused by disharmony between the B. japonica cytoplasm and the R. sativus nucleus. The chlorophyll deficiency is discussed in comparison with male sterility or other characters which sometimes occur in alloplasmic Raphanus and Brassica species.     

氮肥对杂交小麦果聚糖积累与转运及其杂种优势的影响

氮肥影响作物的碳氮代谢及生长发育。选用６个杂交小麦及其7个亲本材料在施氮（200 kg /hm²）和不施氮（0 kg /hm²）条件下，比较研究了不同生育期不同器官果聚糖的积累与转运及其杂种优势。无论施氮与否茎鞘和总麦草中果聚糖的积累模式基本相似。茎鞘是贮存果聚糖的主要营养器官，分配了总麦草果聚糖积累量的63%～87%，并在开花期其积累量达最大值。总麦草转运的85%以上的果聚糖来源于茎鞘，其对籽粒产量的贡献率最大（9.42%~19.36%）。氮缺乏减少叶片中果聚糖的积累量，但增加茎鞘和总麦草中果聚糖的积累量。穗轴及颖壳、茎鞘和总麦草的果聚糖积累在挑旗期、抽穗期和开花期存在一定的杂种优势（4.7%~51.7%），叶片、茎鞘和总麦草的果聚糖转运量、转运率也具有较强的杂种优势，施氮增强叶片中果聚糖的转运优势，但减弱茎鞘和总麦草中的转运优势。结果说明，杂交品种比其亲本具有更强的果聚糖转运能力，施氮对茎鞘果聚糖的积累与转运及其杂种优势均有抑制作用。     

Allelic variation in linolenic acid content of high erucic acid Ethiopian mustard and incorporation of the low linolenic acid trait into zero erucic acid germplasm

Zero erucic acid germplasm of Ethiopian mustard is characterized by high levels of linolenic acid (about 21%). Two genetic sources of low linolenic acid (N2‐4961 and HF‐186, about 5%), have been developed in a high erucic acid background. The objectives of this research were to study the genetic relationship between the two low linolenic acid lines and to transfer the trait to zero erucic acid germplasm. F1 seed generations from crosses between both lines had higher average linolenic acid concentration than both parents. F2 seeds segregated for linolenic acid content following a continuous variation from 1.8 to 7.4%, exceeding the limits of the parental distribution ranges. Transgressive recombinants with very low linolenic acid concentration (0.7‐2.7%) were confirmed in the F3 seed generation. The results suggested that N2‐4961 and HF‐186 possess alleles for low linolenic acid at different loci. Transgressive low linolenic acid F3 plants were crossed with plants of a zero erucic acid line and a selection for zero erucic, low linolenic acid was conducted. As a result, a zero erucic acid F3:4 line containing 1.5 ± 0.7% linolenic acid was developed.