Rhizobium Proliferation-Supporting Substances in Seed Exudates of Common Bean (Phaseolus vulgaris L.)

Seed exudates collected from three cultivars (cv. Hokkaikintoki, Himetebou, and Kurodane-kinugasa) of common bean ( Phaseolus vulgaris L.) were fractionated based on several physicochemical properties, and the nutrient substances in the fractions effective for Rhizobium proliferation were determined. Regardless of the common bean cultivars, the low molecular weight and high polarity fraction showed the most beneficial effect on Rhizobium proliferation. After further separation of the low molecular weight and high polarity fraction, the promoting effect was detected in the non-ionic and the cationic plus ampho-teric subtractions. Although the amount of sugars or amino acids exuded from a seed was, respectively, similar in all the cultivars except for the sugars in Kurodanekinugasa, the content of these compounds per seed-weight was inversely proportional to the seed size. Ten sugars and twenty-one amino acids were, respectively, identified in the non-ionic and cat-ionic plus amphoteric subtractions, and there were some differences in the composition of these substances between common bean cultivars.     

Primary and secondary metabolite composition of kernels from three cultivars of Portuguese chestnut (Castanea sativa Mill.) at different stages of industrial transformation

Chestnut (Castanea sativa) is an important basic food in rural diets and a major starch crop used in a similar way to potatoes. Chestnuts are a fundamental economic resource in the "chestnut regions" not only for the fruit but also for the chestnut wood. Chestnuts have become increasingly important with respect to human health, for example, as an alternative gluten-free flour source. Chestnuts are also a rich source of other beneficial compounds, but there have been few studies on the composition during processing. In this study, we analyzed the chemical composition of three Portuguese cultivars at different stages of industrial processing. The chestnut cultivars were Longal, Judia, and Martaínha. All three cultivars had high moisture contents but were low in ash, crude fat, and crude protein contents, with high starch and low fiber contents. The free amino acid contents, including various essential amino acids, varied depending on the cultivar. All three cultivars also had a significant content of polyphenolics with gallic acid; ellagic acid was predominant among hydrolyzable and condensed tannins. Many of these compounds are known to exert significant positive effects on human health. The one-way analysis of variance for fresh chestnut shows significant differences among the three cultivars for most of the studied parameters. The same statistical analysis applied to each one of the two cultivars (Judia and Longal) sampled for the four processing steps analyzed indicates a significant effect of this factor in practically all of the constituents. On the other hand, the two-way analysis of variance shows that, besides the residual, the processing step and the interaction cultivar x processing step were the factors that more contributed for the total variation observed in the constituents analyzed, while the contribution of cultivar was much less significant.     

Growth Parameter and These Ratio Ionics Responses of Three Cultivars Pistachio to Low and High Salinity

Salinity as a major abiotic stresses is one of the main challenges in world’s agricultural productions. The aim of this work was to study the effect of salinity on growth parameter and these ratio ionics responses of three cultivars pistachio. The experiment was arranged in a randomized complete block design consisting of a 3 × 4 factorial combination of three pistachio cultivars (Akbari, Aghaei, and Kalle-Ghuchi) and four salinity levels (1, 5, 10, and 15 dS/m sodium chloride) with three replications. The results showed that the Aghaei cultivars having a high ratio of potassium (K)/sodium (Na) and maintain this ratio at different levels of salinity and Akbari cultivars is sensitive to salinity because of the less ratio of K/Na.     

Leaf area index response of four obsolete and four modern cotton cultivars to two nitrogen levels

The optimal nitrogen (N) rate for cotton (Gossypium hirsutum L.) production in the late 20th century is greater than it was in the middle of the century (112 versus 27 kg ha^‐1). Part of the reason for this difference is that modern cultivars exhibit a greater harvest index than obsolete cultivars. This greater harvest index helps to allow modern cultivars to utilize greater N rates. However, factors other than harvest index, such as the development of leaf area in response to N, may also play an important role. Therefore, the objective of this study was to characterize leaf area index (LAI) of four obsolete and four modern cultivars at a low and high fertilizer N level. Cotton was grown in the field for two years (1992 and 1993) with two locations each year. The locations were a Beulah fine sandy loam and a Dubbs silt loam. Two preplant fertilizer‐N rates were used, a low (22 kg N ha^‐1) and a high(112 kg N ha^‐1). Leaf area index was determined at three stages in each year (early, mid, and late season). Yield was determined at maturity. Averaged across years, locations, and cultivars, late‐season LAI increased from 2.32 at 22 kg N ha^‐1 to 3.15 at 112 kg N ha^‐1 by late season. In 1992, modern and obsolete cultivars had similar LAI responses to N at early and mid season but by late season, LAI of modern cultivars was greater under high N than the obsolete cultivars (3.53 versus 2.95). Lint yield of the four modern cultivars was 372 kg ha^‐1 greater than the four obsolete cultivars at 112 kg N ha^‐1 and 289 kg lint ha^‐1 greater at 22 kg N ha^‐1 in 1992. The LAI response to N level of the modern cultivars was similar to that of obsolete cultivars in 1993 at all three sampling dates. In 1993, the lint yield of modern cultivars was 238 kg ha^‐1 greater than obsolete cultivars under 112 kg N ha^‐1 and 182 kg lint ha^‐1 at 22 kg N ha^‐1. In summary, our results best support the hypothesis that the higher yield of modern cultivars at high fertilizer N is unrelated to their LAI.     

Level and Transmission of Genetic Heterozygosity in Apricot (Prunus armeniaca L.) Explored Using Simple Sequence Repeat Markers

In this study, 17 peach simple sequence repeat (SSR) sequences were used in the exploration of the genetic heterozygosity level of several apricot cultivars from Spain, France, Greece, and the USA, and 23 descendants. The genotypes can be classified in three groups as a function of their genetic heterozygosity (1) local cultivars from Murcia (Spain) (‘Gitanos’ and ‘Pepito del Rubio’) and several descendants from crosses among these cultivars, with very low genetic heterozygosities (less than 0.30); (2) cultivars from France and Spain (‘Moniquí’, ‘Currot’ and ‘Bergeron’) and several descendants, with intermediate levels of genetic heterozygosity (around 0.45); and (3) cultivars ‘Orange Red’ and ‘Goldrich’ from North America and ‘Lito’ from Greece, with the remaining descendants, having genetic heterozygosities higher than 0.50. The results showed the high increase of genetic heterozygosity in the case of descendants from complementary crosses. The use of cultivars from North America could increase greatly the genetic heterozygosity in the Spanish apricot breeding programs, enlarging the genetic variability of the local cultivars. On the other hand, in the case of transgressive crosses among local Spanish cultivars, the increase of genetic heterozygosity was much lower.     

不同生态条件下氮高效水稻品种干物质积累和产量特性

  【目的】  研究生态条件和施氮水平及其互作对氮高效水稻品种干物质积累、物质转运和产量的影响,为不同稻区不同施氮水平下选择适宜的水稻品种提供科学依据。  【方法】  本试验于2019年在四川省大邑县(弱光寡照)和云南省永胜县(光温充足)两个生态点进行,以西南地区大范围种植的10个水稻品种为供试材料,采用两因素裂区设计,主区为不施氮(N0)、低氮120 kg/hm2 (N120)和高氮180 kg/hm2 (N180) 3个施氮水平,副区为10个品种。分别于拔节期、抽穗期和成熟期测定干物重,计算不同时期干物质积累和转运量,于收获后测定水稻产量。  【结果】  水稻产量和干物质生产特性为生态条件、施氮水平、品种及其互作效应共同作用的结果。大邑生态点宜香优1108在N120下的产量比N180提高4.68%,永胜点德优4923在N120施氮水平下的产量比N180提高113.4 kg/hm2,结合产量和GGE模型分析,大邑生态点宜香优1108为低氮高效型,晶两优534和F优498为高氮高效型;永胜点德优4923为低氮高效型,中优295和丰优香占为高氮高效型。氮高效水稻干物质积累和转运特征因生态条件和施氮量的变化而变化。大邑低氮高效型品种产量主要来自拔节前干物质的积累和抽穗前光合产物的转化,产量优势在于足量的单位面积有效穗数,移栽至拔节期的群体生长率与产量(r=0.70**)和有效穗数(r=0.41*)呈显著正相关;大邑生态点高氮高效型品种抽穗至成熟期群体生长率和穗后干物质积累量对籽粒的贡献率明显高于其它品种,产量与抽穗至成熟期群体生长率(r=0.56**)和穗后干物质积累量对籽粒的贡献率(r=0.37*)呈显著正相关关系;永胜低氮高效型品种干物质积累特征在于拔节至抽穗期群体生长率和穗前干物质转化对籽粒的贡献率较高,千粒重较同处理平均值提高13.61%;永胜高氮高效型品种具有拔节至抽穗期高群体生长率的物质生产特性,产量优势在于较高的每穗颖花数,该点拔节至抽穗期群体生长率与产量(r = 0.60**)和每穗颖花数(r = 0.68**)均呈极显著正相关关系。  【结论】  在大邑等弱光寡照地区,低氮高效型品种应保证前期较高的生长速率和穗前干物质转化对籽粒的贡献率;高氮高效型品种应保持抽穗后高群体生长率并增加穗后光合产物的积累。在永胜等光温充足地区,拔节至抽穗期较高的群体生长率是低氮高效型和高氮高效型品种共同的物质生产特征。     

Impact of highly varying seeding densities on grain yield and yield stability of winter rye cultivars under the influence of delayed sowing under sandy soil conditions

The objective of this study was to determine how to establish high and stable yields of winter rye under the impact of highly varying seeding densities and delayed sowing date. A field trial with three winter rye cultivars (two population cultivars and one F1 hybrid) was conducted on a sandy site over a period of three years. The results showed that seeding density, cultivar choice, and annual weather conditions are important factors impacting the yield variability of winter rye. Higher seeding densities led to higher and slightly more stable yields of winter rye. Moreover, a cultivar-adapted seeding date seemed to exploit yield potential advantageously. Interestingly, all three cultivars showed better yield stability with a two-week delay in seeding date. This study suggests that cultivar choice and management practices such as modulation of seeding date and seeding density play an important role in improving the grain yield and yield stability of winter rye.     

不同番茄品种镁吸收特性比较

【目的】 通过研究不同番茄品种对镁吸收的差异,为缺镁地区番茄镁高效品种筛选提供理论依据。 【方法】 以北方日光温室主栽的3个番茄品种中杂9号、改良毛粉、金棚朝冠为研究对象,将培育苗分别于15℃和30℃下,在镁浓度为0、0.6、1.2、1.8、2.4、3.0 mmol/L的营养液中吸收 24 h,通过养分吸收动力学方法确定吸收参数来比较不同番茄品种间的差异。同时将相同的3个番茄品种在不加镁 (0 mmol/L) 和中等镁 (1 mmol/L) 浓度条件下水培45 d,比较镁吸收量、镁流入速率及番茄对镁吸收利用的差异。 【结果】 养分动力学试验结果表明,15℃时番茄对镁的吸收速率高于30℃,两个温度条件下,3个番茄品种对镁的吸收速率均表现为改良毛粉 > 金棚朝冠 > 中杂9号。3个品种最大吸收速率 (I _max) 和亲和力系数 (K_m) 均有显著差异,I_max和K_m值均为改良毛粉 > 金棚朝冠 > 中杂9号。培养45 d的结果表明,在缺镁和中等镁浓度条件下,3个番茄品种镁吸收量、镁流入速率均有显著差异,其中改良毛粉镁吸收量显著低于金棚朝冠和中杂9号,金棚朝冠和中杂9号间差异未达显著水平。 【结论】 温度影响番茄对镁的吸收,但并未改变品种间的差异。低镁条件下,金棚朝冠和中杂9号对镁具有较大吸收潜力,改良毛粉的吸收潜力显著低于前两者。      

The effect of calcium nutrition on the sterol content of tobacco roots and their susceptibility to Phytophthora parasitica var. nicotianae

The influence of nutrient solutions containing low (25 mg/1) and high (250 mg/1) calcium (Ca) concentrations on the total lipid, free sterol, sterol glycoside and steryl ester content and on the subsequent susceptibility of three flue‐cured tobacco cultivars to black shank, incited by Phytophthora parasitica var. nicotianae was investigated. The total lipid, total sterol and free sterol content differed appreciably among root systems of the three cultivars grown at high Ca. Roots of plants grown at low Ca contained relatively higher proportions of steryl glycosides and lower proportions of free sterols than roots of plants grown at high Ca, although the absolute sterol concentrations also differed significantly among the roots of cultivars grown at low Ca. Black shank disease development was significantly lower in roots of susceptible plants grown at low Ca than in roots of the same cultivar grown at high Ca. The innate susceptibility of the cultivars were not related to the lipid or sterol content. The reduced disease development of plants grown at low Ca appeared to be associated with changes in membrane permeability, which may be correlated with changes in the various sterol fractions.     

烟叶氨气补偿点的品种间差异及其与氮素代谢的关系研究

为了研究不同成熟特性的烤烟品种叶片氨气补偿点及其差异,利用质外体提取方法对3个烤烟品种NC89、K326和中烟90的叶片质外体铵浓度和pH值进行了测定,并计算不同品种叶片的氨气补偿点(25℃);同时探讨了氨气补偿点与氮素代谢的关系。结果表明,叶片氨气补偿点随着成熟衰老而上升;烟草叶片成熟衰老期氨气补偿点与谷氨酰胺合成酶活性关系密切。衰老速度快、叶片氮素状况（总氮和可溶性蛋白）低的品种谷氨酰胺合成酶活性下降幅度大,氨气补偿点升幅大,绝对值也高。因此,衰老速度快、叶片氮素状况低的品种在叶片衰老期具有更大的氨挥发潜力。品种间氨气补偿点的差异与它们的氮素代谢特性有关。     

大麦不同氮利用效率品种筛选及GS2基因的表达分析

为探明大麦品种的不同氮利用效率差异及质体型谷氨酰胺合成酶基因的表达差异,以48份大麦品种为材料,并利用不同氮水平营养液水培8周,研究其在低氮(0.4 mmol·L~(-1))、中氮(2.0 mmol·L~(-1))及高氮(5.0 mmol·L~(-1))下根、茎、叶的相关性状,筛选氮高效利用和氮低效利用的大麦品种,并利用qRT-PCR对筛选到的大麦氮高效和氮低效品种的GS2基因表达特性进行分析。结果表明,中氮下,除根干重和根含氮量外,其余的大麦苗期根、茎、叶各生物性状在品种间差异极显著,根据不同氮处理下的48份大麦品种苗期性状以及氮利用效率,筛选到1个氮高效品种(Z0099001)和2个氮低效品种(ARr-91和甘啤7号)。3个氮处理水平下,氮高效品种GS2基因的相对表达量高于氮低效品种,并且氮高效品种和氮低效品种根、茎、叶中GS2基因的相对表达量也各不相同,其中,叶中最高,茎中次之,根中最低。低氮条件下,根茎叶中,Z0099001的GS2基因的相对表达量高于甘啤7号,ARr-91最低。中氮条件下,根、茎、叶中均表现为氮高效品种高于氮低效品种,但在根中差异不显著,茎和叶中差异显著。高氮条件下,3个品种在根中GS2基因的相对表达量较低;在茎和叶中,Z0099001的相对表达量显著高于ARr-91和甘啤7号,且Z0099001叶中GS2基因的相对表达量在所有性状中最高。本研究结果为进一步解析大麦氮高效利用率奠定了基础。     

The effect of sulfur fertilizer on glucoraphanin levels in broccoli (B. oleracea L. var. italica) at different growth stages

Three sulfur (S) treatements were imposed by applying gypsum to three broccoli cultivars (Claudia, Marathon, and TB-234) known to differ in glucoraphanin content of mature seeds. The S treatments were control (very low added S), low S (23 kg S ha(-)(1)), and high S (92 kg S ha(-)(1)). The gypsum applications during the early vegetative phase of the three broccoli cultivars increased S uptake and the glucoraphanin content in each plant organ. There were significant genotypic differences for the content of both S and glucoraphanin in all plant organs at different growth stages with gypsum applications. A large increase in S and glucoraphanin content was found in the green heads of broccoli and mature seeds. S present in glucoraphanin accounted for only 4-10% of total S content in broccoli heads. However, S present in glucoraphanin in mature seeds accounted for 40-46% of the total S in the seeds of moderate and high glucoraphanin cultivars (Marathon and TB-234). The partitioning of S into glucoraphanin also increased with gypsum applications. Differences in S uptake, S distribution between organs, and partitioning of S into glucoraphanin largely explained the differences in glucoraphanin content in the green heads and mature seeds for the three broccoli cultivars and three S treatments.     

甜菜品种（系）的ISSR标记数字指纹图谱构建及聚类分析

摘要：本文针对来源于荷兰的4个引进甜菜品种和国内的6个甜菜品系（其中2个为一年生野生甜菜）进行了ISSR指纹图谱构建和聚类分析研究。筛选出稳定性高且多态性好的6个引物用于试验。利用筛选的6条引物ISSR-PCR 共扩增出51个条带, 其中多态性条带百分率为86.3%. 利用该6条引物ISSR-PCR建立的指纹图谱能将试验中的全部甜菜品种都鉴定区分开。只利用2条引物L1和UBC846 扩增的8个多态性条带构建了10个甜菜品种（系）的数字指纹识别码,该数字指纹图谱能完全区分10个甜菜品种（系）,结果显示ISSR 指纹图谱能非常有效的鉴定不同的甜菜品种。利用生物软件NTSYS-pc针对10个试验甜菜品种（系）的ISSR 扩增条带进行遗传相似性聚类分析,结果显示10个甜菜品种（系）的相似系数为0.43与0.83之间,平均为0.62。利用非加权组平均法（UPGMA）进行聚类分析,结果显示10个甜菜品种（系）聚类为2个组和3个亚组。UPGMA 聚类分析能清楚的显示10个甜菜群体间的遗传关系并且聚类结果与10个甜菜群体的特性一致, 说明ISSR标记能用于甜菜不同群体间遗传距离的评估。     

Genetic diversity of storage protein genes in common wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) cultivars from China and its comparison with genetic diversity of cultivars from other countries

Contemporary trends and perspectives of Chinese winter wheat breeding programs were explored using multiple alleles of gliadin (Gli) and glutenin (Glu)-coding loci as genetic markers. To estimate genetic diversity and specific features of Chinese cultivars, the allele frequencies and genetic diversity H in Chinese wheat pool were calculated and compared to those of cultivars from 11 regions of the world. Among all these cultivars the Chinese ones exhibited the highest allelic diversity of the Gli loci while showing relatively low genetic variability for the Glu loci. Most (96%) of the cultivars examined had unique Gli allele compositions, which enabled to differentiate these cultivars with high precision. Cluster analysis of the genetic distances among the wheats from different regions showed that the Chinese cultivars were close to Italian and Russian ones, sharing with them the common Gli alleles. Clustering of modern cultivars and that of cultivars bred 10–15 years ago was essentially the same. All cultivars from all of the countries examined were classified into three groups according to their quality based on their Glu allele compositions. The Chinese cultivars showed a moderate quality score of 7.0, which conforms to the quality evaluation based on SDS sedimentation. This quality proved to be insufficiently high as compared to cultivars from other countries. However, the genetic diversity estimation suggests that Chinese cultivars have a potential for quality improvement.     

Solubilization of Arabinoxylans from Isolated Water-Unextractable Pentosans and Wheat Flour Doughs by Cell-Wall-Degrading Enzymes

Water-unextractable pentosans (WUP) isolated from the flours of three wheat cultivars (Apollo, Soissons, Thésée) were treated with enzymes to solubilize the arabinoxylans. The water-unextractable arabinoxylans from the three cultivars had similar susceptibility to solubilization by enzymes: Grindamyl S 100 (GS100), a commercial preparation for baking, rich in pentosanase activities that originated from an Aspergillus niger culture; and three endoxylanases (E1, E2, E3), an arabinofuranosidase (Af), a β- glucanase (βG), and a ferulate esterase (FAE) purified from GS100. A cellulase (C) and a pure endoglucanase (eG) from Trichoderma reesei were also used. GS100 was able to solubilize high molecular weight arabinoxylans (HMWAX) from WUP that markedly enhance the viscosity of the reaction mixture supernatants. The endoxylanase E1 was responsible for this solubilizing activity of GS100, whereas E2 and E3 made only a very low contribution. Combining E1 with FAE led to a limited increase in the arabinoxylan-solubilizing effect. Also, enzymes hydrolyzing cellulose and β-glucans slightly improved the arabinoxylan solubilization from WUP when combined with GS100 or E1, but produced arabinoxylans of lower intrinsic viscosity. Similar effects of the enzymes were observed on arabinoxylan solubilization when applied to dough instead of isolated WUP.     

Novel loss-of-function putative aminotransferase alleles cause biosynthesis of capsinoids, nonpungent capsaicinoid analogues, in mildly pungent chili peppers (Capsicum chinense)

Capsinoids are a group of nonpungent capsaicinoid analogues produced in Capsicum fruits. They have similar bioactivities to capsaicinoids such as suppression of fat accumulation and antioxidant activity. They are more palatable ingredients in dietary supplements than capsaicinoids because of their low pungency. Previous studies on nonpungent Capsicum annuum cultivars showed that capsinoid biosynthesis is caused by loss-of-function putative aminotransferase (p-amt) alleles. This study showed that three mildly pungent cultivars of Capsicum chinense (Zavory Hot, Aji Dulce strain 2, and Belize Sweet) contain high levels of capsinoid. It was shown that these cultivars have novel p-amt alleles, which contain mutations that differ from those of C. annuum. Sequence analysis of p-amt in Belize Sweet revealed that a 5 bp insertion (TGGGC) results in a frameshift mutation. A transposable element (Tcc) was found in the p-amt of Zavory Hot and Aji Dulce strain 2. Tcc has features similar to those of the hAT transposon family. This was inserted in the fifth intron of Zavory Hot and in third intron of Aji Dulce strain 2. The p-amt alleles harboring Tcc cannot produce an active p-AMT. These mildly pungent cultivars will provide a new natural source of capsinoids.     

不同基因型水稻苗期氮营养特性差异及综合评价

氮肥过量施用,不仅造成氮肥大量流失,还增加了农业生产成本,对生态环境带来了巨大的威胁。筛选氮高效基因型水稻品种是提高氮素利用效率、降低环境污染的有效途径。本文利用营养液培养方法,研究了55个水稻品种(系)在相同供氮水平(40 mg·L~(-1))、不同供氮形态(NH_4~+-N和NO_3~–-N)条件下苗期吸收与积累氮素的差异。并采用隶属函数法将评价指标进行标准化,基于氮效率综合值,运用分层聚类热图分析,进行55个水稻品种氮效率类型的划分,为氮高效水稻品种的筛选提供依据。在NH_4~+-N和NO_3~–-N培养下,不同水稻品种的整株生物量、茎叶生物量、根系生物量、根系氮含量、茎叶氮累积量差异性显著,变异系数分别在0.69~0.80和0.57~0.74之间。通过因子分析发现,在NH_4~+-N和NO_3~–-N培养条件下的主成分情况相同,第1主成分由整株生物量、茎叶生物量、根系生物量、整株氮累积量、茎叶氮累积量、根系氮累积量决定,主要为反映植株的生物量及氮素累积量指标;第2主成分由不同器官的氮含量决定。综合水稻苗期氮素吸收累积变异特征及因子分析,将整株生物量、茎叶生物量、根系生物量、茎叶氮累积量作为水稻苗期氮高效综合评价指标。根据隶属函数法计算出的氮效率综合值和采用欧氏距离平方拟合的分层聚类热图,55个供试水稻品种可分为氮高效型、氮中效型、氮低效型3大类,分别占供试品种总数的10.91%、27.27%、61.82%。在NH_4~+-N和NO_3~–-N供应条件下,初步确定‘广两优3905’、‘甬优9号’、‘中籼2503’、‘Ⅱ优602’、‘两优766’和‘深两优1813’为氮高效型品种。     

Evaluation of genetic identity and variation of local apple cultivars (<Emphasis Type="Italic">Malus</Emphasis> × <Emphasis Type="Italic">domestica</Emphasis> Borkh.) from Spain using microsatellite markers

A collection of 114 local cultivars of Malus × domestica Borkh. from the Northwest of Spain and a group of 26 non-native commercial cultivars, were studied in order to determine the level of genetic differentiation between them, to know the population genetic structure of the three main production regions in North Spain, and to detect possible duplications, misidentifications, and intrusions of foreign cultivars into the present day Spanish apple gene pools. Ten primer pairs of microsatellite loci were selected from previous studies on apple. Allelic frequencies were used to estimate the average expected heterozygosity (Hexp) and F-statistics. A Principal Component Analysis and a Cluster Analysis were conducted in order to determine the relationships among cultivars. Considering all populations (Spanish and commercial cultivars) we found 119 alleles with the 10 microsatellites; 10 out of 119 were rare (with frequencies lower than 0.01). Spanish cultivars can be used as references for those alleles for further studies since they are available in Germplasm banks. Triploid cultivars were quite frequent, 39 out of 140, with the highest number occurring in Galicia (29 cultivars). North Spain presented a high variability for apple according to heterozygosity levels. Microsatellites have provided useful information about the singularity of Spanish apple cultivars, revealed six groups of synonymies and five introgressions of commercial cultivars.     

增加烟草一级和二级侧根是抵御干旱的生理机制

【目的】 挖掘植物自身的抗旱能力是提高农业水分利用效率的有效措施。本研究通过比较水分胁迫处理下 5 个烤烟品种苗期根系发生和伸长以及叶片光合特性的变化,探讨烤烟抗旱能力差异的生理机制,为烟草生产的可持续发展提供理论依据。 【方法】 采用水培试验,设置对照和水分胁迫处理 (添加 2.5% PEG 处理来模拟中度干旱),研究 5 个烤烟品种苗期的地上部和根系的生物量、一级和二级侧根的发生和伸长,利用 Li-Cor 6400 光合测定系统测定叶片的光合速率和气孔导度等参数,利用 FLIR 手持式红外热成像仪测定新展开叶的叶片温度,分析烟草抗旱能力差异明显的生理机制。 【结果】 水分胁迫条件下 5 个烤烟品种的生长差异明显。与对照处理相比,水分胁迫对大平板和农大 202 的生长影响不明显,但柳叶尖、金星 6007 和中烟 100 的地上部和根系生物量显著被抑制,降幅范围在 66%～83%,达到差异极显著水平。水分胁迫抑制 5 个烤烟品种一级和二级侧根的伸长,但大平板和农大 202 的一级侧根数目和二级侧根密度显著增加,最终导致根系生物量没有下降;另外 3 个烟草品种柳叶尖、金星 6007 和中烟 100 的侧根发生增加趋势不明显。水分胁迫处理下抗旱能力强的大平板和农大 202 地上部生物量和叶片温度变化不明显,而叶片的净光合速率显著下降,但其降幅显著低于 3 个抗旱能力弱的烤烟品种。与对照处理相比,抗旱能力弱的柳叶尖、金星 6007 和中烟 100 叶片的气孔导度和蒸腾速率显著下降,叶片温度上升 5～7℃。进一步的研究表明,PEG处理下耐旱能力强烤烟品种侧根数目的显著增加是地上部维持较强光合能力的主要原因。 【结论】 抗旱能力强的烟草品种苗期受到水分胁迫时其一级和二级侧根显著增加,进而能保持较高的光合特性。      

Influence of cultivar,cooking, and storage on cell-wall polysaccharide composition of winter squash (Cucurbita maxima)

Changes in the cell-wall polysaccharides (CWP) of the edible tissues of four winter squash cultivars during storage and after cooking were investigated. A procedure for isolating cell walls of tissues containing high levels of starch was used. The starch-free CWP were sequentially fractionated using CDTA, dilute Na(2)CO(3), and 4 M KOH. Cellulose made up 40-42% of the total CWP for three cultivars (Delica, CF 2, and CF 4) at harvest but was 35% in the softer Red Warren. The pectic polysaccharides of Delica, CF 2, and CF 4 cell walls are more branched than those from Red Warren squash. The higher proportion of uronic acid in the pectic polysaccharides of Red Warren squash correlates with its lower firmness. Cooking resulted in an increase in the water-soluble pectins and a decrease in the pectins associated with cellulose. The total CWP content of the squash cultivars remained unchanged for up to 2 months of storage and then markedly decreased between 2 and 3 months of storage. The galactose content of Delica and Red Warren cell walls remained relatively constant from harvest to 2 months of storage and then decreased markedly during 2-3 months of storage.