The effect of nitrogen fertilization on plant growth and the nitrate content of leaves and roots of parsley in the Mediterranean region

Curly-leafed and turnip-rooted parsley have recently been introduced to Greece as alternative herbs within the programme for crop diversification. Because the response of these subspecies to nitrogen (N) application under the warm climatic conditions of the Mediterranean region is unknown, both were cultivated over three consecutive years in order to evaluate their yield potential and quality (in terms of nitrate content) in relation to nitrogen application in comparison with the traditionally cultivated plain-leafed subspecies. Nitrogen was applied as ammonium nitrate in the form of liquid feeds at rates of 30–450 mg kg⁻¹. Foliage and root yield increased with N application up to a level of 150 mg kg⁻¹ and the nitrate content of the tissues was low. Increasing N application rates to 300 or 450 mg kg⁻¹ did not cause a further increase in yield, but the nitrate content of the tissues increased. In view of health concerns with respect to human nitrate intake and environmental threats posed by excessive N application, it is concluded that the optimum level of ammonium nitrate application under local conditions should be 150 mg kg⁻¹. Overall, all three subspecies responded to N in a similar way in terms of yield and nitrate content.     

利用SSH分离TDZ诱导金钗石斛成花相关基因

 以金钗石斛（Dendrobium nobile Lindl.）腋芽为材料,利用抑制消减杂交（SSH）技术构建了TDZ处理后金钗石斛腋芽的正向和反向SSH文库。通过PCR和反向Northern杂交验证后,得到的正向文库的314个阳性克隆和反向文库的59个克隆测序后经过聚类,最终得到39条受TDZ正向调控的EST序列,以及21条受其反向调控的EST序列。对其中某些差异基因进行半定量RT-PCR,结果显示这些基因的表达受TDZ的影响。利用Blastn和Blastx进行比对分析,其中20个没有同源序列,属于未知功能基因。其余序列的同源基因编码的产物参与包括光合作用、合成代谢、转录调控等多种生物学过程。在反向文库中分离到1个MADS-box基因的同源序列和1个Sos同源基因,而正向文库中存在多个反转录转座子,这些结果表明TDZ可以影响开花过程中的某些转录因子和信号基因的表达,进而促进金钗石斛开花。     

环境因子对万寿菊开花的影响

通过分析不同营养配比和pH值处理万寿菊水培液的开花情况,试验得出,增施磷肥对万寿菊开花的影响较小;配施磷钾肥主要影响万寿菊的单株花朵数和花型大小;而配施钾肥对万寿菊的花期、单株花朵数和花型大小均有较好的影响。万寿菊开花较适宜的水培条件是pH值6．5,即弱酸到中性的环境。此时万寿菊的花期较长、花型较大、单株花朵数较多,花的颜色也最靓丽。     

江坪河放空洞有压洞口段衬砌混凝土冬季温控方案分析

冬季衬砌混凝土施工面临的寒潮等问题,容易导致混凝土产生裂缝.基于有限元分析软件ANSYS,对江坪河放空洞有压段洞口段衬砌厚度为1.0 m的混凝土的拆模时间、围岩特性以及在遭遇寒潮时保温与否等6种不同的方案的进行了分析,并提出相应的温控方案和温控标准供设计与施工参考.     

不同有机肥对有机茶园茶叶产量及开花量影响的研究

为了研究不同有机物料在有机茶园中的施用效果,在八年生有机茶园内设置4种无害化有机物料、3个不同水平的处理,研究这些处理对福鼎种茶树生产性状、鲜叶生化品质及开花量的影响。试验结果表明:与空白对照相比,各种无害化有机物料处理均可显著改善茶树的生长,提高茶叶的产量,改善茶叶的品质,降低开花量,提高经济效益。芽重增加17.06%~42.06%,茶芽密度提高20.9%~36.4%,茶青的产量提高41.26%~93.4 9%,开花量降低2 1.6 7%~4 6.8%,产值增加1 757~3 223元/6 6 7 m2不等;茶叶的水浸出物、茶多酚、氨基酸、咖啡碱等品质成分含量比对照有明显增加。     

Structure and variation of subterranean clover populations from Sicily,Italy

Summary A collection of subterranean clover lines singled out from populations of the species Trifolium brachycalycinum and T. subterraneum collected in Sicily, Italy, was examined at two localities for flowering time and at one locality for oestrogen content and seed yield. The structure and variation of the populations of the two species were compared. The relationship between flowering time of the populations and some environmental features of their collection sites was examined to assess whether the maturity requirements of the two species were similar and to frame selection models focused on developing varieties of appropriate maturity. Populations of T. subterraneum were, on average, more complex than those of T. brachycalycinum, being characterized by higher number of lines per population and greater intra-population variation for flowering time, oestrogen content and seed yield. Furthermore, populations of T. subterraneum were, on average, about 15 days earlier than sympatric populations of T. brachycalycinum. Both the greater variation and the relative earliness of T. subterraneum occurred irrespective of the environments of origin of the populations. Inferences are drawn on the adaptive advantages that such features confer to T. subterraneum. Mean flowering time of the populations increased on increasing annual rainfall and altitude of the collection sites. However, the changes in maturity appeared almost exclusively related to variations in rainfall in T. subterraneum, while in T. brachycalycinum the effect of altitude was greater and that of rainfall less marked than in the former species.     

Flowering behaviour,male sterility and berry setting in tetraploid Solanum tuberosum germplasm

Summary Six hundred and seventy six accessions of cultivated potato (Solanum tuberosum ssp. tuberosum) from 25 countries, were studied for flowering and fruiting behaviour under long days (12–14 h). Flowering intensity ranged from dropping of floral buds just after initiation to profuse blooming. The majority (58.3%) of the accessions bloomed profusely, though 20.4% of the accessions did not bloom at all. Weeks to flowering ranged from 6 to 15 and the majority (66.5%) of the flowering accessions bloomed within 8 to 9 weeks after planting. Duration of flowering ranged from 1 to 10 weeks and the majority (68.1%) of the flowering accessions bloomed for 1 to 4 weeks only. Twentythree per cent of the flowering accessions were completely male sterile. Maximum male fertility was 90% only. No berry setting was observed in 31.8% of the flowering accessions. Only 54.3 per cent of the accessions were found to be fertile in all respects and could be used both as male and female parents. Premature bud abscission was the major cause of sterility. Peru was the best source of profuse-flowering genotypes, Poland was the best source of early flowering genotypes and Mexico was the best source of long duration flowering and good berry setting genotypes. The results suggested that flower bud formation; the growth and development of mature flowers; weeks to flowering and duration of flowering are independent characters controlled by different genes of quantitative nature. Berry setting and duration of flowering were closely associated (r=0.95). Genetic as well as environmental factors interfered with the developmental process leading to flower production and berry setting at different times in different genotypes. The practical implications of these results for true potato seed production are discussed.Publication No. 1298, CPRI, Shimla.     

Effects of photoperiod and temperature on flowering in mungbean (Vigna radiata (L.) Wilczek)

Summary Forty strains of mungbeans, including all of the entries in the 1st and 2nd International Mungbean Nurseries (IMN), were grown in plant growth chambers in photoperiods of 12, 13, 14, 15, and 16 hours and mean temperatures of 18, 23, and 28°C. Results show that (1) mungbean strains differ in their flowering response to photoperiod and to mean temperature; (2) increasing the photoperiod of reducing the mean temperature delayed flowering, the amount of delay varied with the strain: (3) variations in mean temperature may alter the effect of the photoperiod on flowering in particular strains. Twenty-five strains which flowered in all photoperiod-temperature treatments could be divided into four groups, each group being successively later in flowering. The remaining 15 strains could be divided into four groups, according to their failure to flower within 105 days in specific photoperiod-temperature treatments. Flowering response in the growth chamber is useful in explaining flowering response in the 2nd IMN at three locations varying from 14°N to 49°N latitude.Contribution No 7516 from the Missouri Agricultural Experiment Station.     

Phenological development in spring cereals: response to temperature and photoperiod under northern conditions

Phenological development of spring cereals was investigated using observations from several sites in Finland during the period 1970–1990. Different mathematical models which relate temperature to development rate were examined to predict the duration of phenological phases. A photoperiodic response of plant development before heading was also tested. For all phases the relationship between temperature and development was approximately linear. There was no significant response of plant development to photoperiod. This was explained by consistently long photoperiods in the observational material. Parameters for a linear model were derived from a regression analysis of mean development rate of each phase against mean temperature. However, a different response may occur under higher or lower temperatures or under shorter photoperiods than those experienced here.     

水引发对甜菜种子萌发以及生理特性的影响

为更好地利用水引发技术提高甜菜种子的萌发效果,以甜菜种子TD802为研究材料,以蒸馏水为引发剂,通过发芽试验测得甜菜种子的发芽势、发芽率、发芽指数、活力指数和临界阈值等,筛选有利于甜菜种子快速萌发的引发方法,并进行生理指标的测定。结果表明,处理9的发芽率(91%)和发芽势(90.67%)最好,处理5的发芽指数(41.89)和临界阈值(21.39)在所有组合处理中最好,处理6的活力指数(447.4)最好。处理3和处理7的相对电导率高,对种子损伤最小。处理6丙二醛含量最低,对逆境条件反应较强。处理8抗氧化酶活性最强,可消除逆境胁迫所产生的过氧化伤害。不同温度、预浸种时间的水引发都对甜菜种子有促进作用,其中处理1引发效果最稳定,能够更好地增强种子活力、提高种子的抗逆性。