影响番茄离体培养再生的主要因素探讨

以5个番茄品种的子叶和下胚轴为外植体,对无菌苗的生理状态、激素组合、激素浓度和基因型等影响组培效果的主要因素进行探讨,建立了番茄的高效离体培养再生体系。结果表明,下胚轴和子叶均得到了高达100%的出愈率和95%以上的分化率;最佳的品种是T431;最佳激素组合为ZT1.0mg·L-1和IAA1.0mg·L-1。     

大豆高产理想株型的构成

根据大豆理想株型的概念，分析了大豆的主要生理性状和形态性状与产量的关系，并提出了大豆高产理想株型的合理构成，以期为大豆育种的田间选择和株型育种提供理论依据和实践指导。     

Radiation Balance Components of Maize Hybrids Grown at Various Plant Densities

Components of the energy and heat balances were examined in two maize hybrids grown at three different plant densities (40, 70 and 100 thousand plants per hectare). One of the hybrids was drought tolerant, while the other was bred for cultivation under irrigated conditions. An increase in plant density influenced not only the size of the leaf area, but also the distribution of the leaves at various plant heights. The extinction coefficient, which provides a quantification of radiation penetration, was higher in the irrigated treatments. By contrast to the other two treatments, the plant canopy in the thinly sown stands remained open throughout the vegetation period, and thus behaved quite differently to the closed stands, making it impossible to compare them. Smaller albedo values were recorded for the hybrid bred for irrigation and in thinly sown stands. The low plant density allowed more energy to reach the soil, from which it was reflected, making a considerable contribution to the final temperature in the stand. The latent heat, in keeping with the quantity of water transpired, was the greatest in the densely sown stands. There was little difference between the latent heat values of the normal and dense stands in either hybrid, indicating that they both had a similar sensitivity to increased stand density. If sufficient water is available it would appear that the stand density could be increased even for the drought-tolerant hybrid.     

Analysis of the Impact of Alfalfa Forage Production under Summer Water-Limiting Circumstances on Productivity, Agricultural and Growers Returns and Plant Stand

The trade-off between summer water conservation from alfalfa production and the effects on plant growth, agricultural crop value, and grower returns in the low desert area (Imperial, Palo Verde, Parker and Yuma Valleys of California and Arizona) was analysed using an experimental plot in the Palo Verde Valley. The purpose was to provide a basis for evaluating water conservation decisions and policies. Four summer dry-down periods (withdrawing water for a predetermined period) of 0 days (control), 35 days, 70 days, and 105 days were analysed. Our results show that whereas the various dry-down periods would provide water conservation ranging from 254 to 944 million m³, the region would experience agricultural income decline by US $16 to US $73 million. For growers, benefits of dry-down would be effective only if the water price exceeds US $0.045 m⁻³ in California and US $0.036 m⁻³ in Arizona. Also dry-down would have possible adverse effects in the following areas including declines in plant stand density, long-term productivity, service industry sales, employment and biological benefits of soil fertility and organic matter that is attributed by the alfalfa plant in which case agriculture's and growers monetary losses could increase.     

光棘豆单细胞培养再生植株

由光棘豆种子无菌苗的胚轴和子叶诱导的愈伤组织建立起细胞悬浮系。由悬浮系分离出单细胞。单细胞在含有1～2mg/L 2,4—D的2/3MS培养基中采用振荡和静止两种方法培养。结果表明。振荡培养愈伤组织再生频率较高,所需时间较短。单细胞再生的愈伤组织转入分化培养基后分化出芽。幼苗转入含有IBA和IAA的1/2MS培养基中生根,成为完整的再生植株。在分化培养基中,只有瘤状愈伤组织能够分化出芽。并且较高浓度的细胞分裂素(6—BA或KT)或6—BA与ZT结合使用对愈伤组织的分化是有利的。     

Influence of the Indoleacetic Acid-Lysine Synthetase Gene (iaaL) of Pseudomonas syringae subsp. savastanoi on Yield Attributes of Potatoes

The iaaL gene of Pseudomonas syringae subsp. savastanoi encodes an indoleacetic acid-lysine synthetase which conjugates free indoleacetic acid (IAA) with lysine. lAA-lys is biologically less active than free IAA. The iaaL coding region was expressed under the control of the cauliflower mosaic virus 35S promoter and transgenic potato plants were produced (Spena et al. 1991). 35S iaaL potato plants are characterized by increased internodal length and epinastic bending of older leaves. In three greenhouse experiments with plants grown in pots of different size and in two growth chamber experiments tuber number increased in iaaL transgenic plants compared to untransformed and vector-transformed controls of the same genotype. The increase in tuber numbers observed under controlled conditions was reflected in tuber yield which increased in the pot grown transgenics.     

植物活体水分探测仪的研制及测试初报

利用NIM插件探测器及金硅面垒探头组装了植物活体水分探测仪;筛选并分析了仪器的最佳工作条件;检测了春小麦、玉米、苜蓿、豌豆、红豆草叶片鲜重的变化。结果表明;叶片水分随时间损失大的,其抗旱性差。叶片保水的秩序为:红豆草、豌豆>苜蓿>春小麦>玉米。     

沙区五种珍稀濒危植物水分生理指标测定及分析

本文在测定沙区５种珍稀濒危植物的水分生理指标的基础上，分析了其抗旱性，意在探讨适应干旱环境的特性。研究结果表明：矮沙冬青保水能力与吸水能力强，对干燥炎热的环境有很强的适应性；银沙槐蒸腾强度大，失水快，但吸水力强，补偿水分快；裸果木通过强的保水力适应干旱；绵刺以强的吸水力和抗脱水力适应环境；准噶尔无叶豆以体内水分自我调节作用适应大气干旱。     

城市园林绿化现存问题、对策及其绿化植物配置原则

随着国民经济的不断发展，城市园林绿化已成为现代建设的重要内容。在归结上前城市园林绿化所存共性问题的基础上，针对城市园林绿化普遍存在的4方面问题，提出5点对策。     

Infection pressure of potato virus YN

Potato virus Y^N (PVY^N) infection was determined by the tobacco test in Swifterbant (Eastern Flevoland). In plots with beet, wheat and seed potatoes the infection exhibited an identical course. No differences were found either between PVY^N infection in the border and that in the middle of a field planted with ware potatoes, although infection pressure was clearly higher here than in the plot with seed potatoes. A barrier crop of 10 rows of wheat did not decrease the infection pressure of the virus.From August onwards, the spread of PVY^N in Lienden (Betuwe) was followed. Here virus transmission was found continuously, even until mid-November.Potato volunteers outside as well as in potato fields are serious infection sources. In 1976 and in 1977 virus spread was detected before the flight ofMyzus persicae, as determined with yellow Moericke traps. Infection pressure can be measured more efficiently by the tobacco test than by aphid trapping. The effect of rogueing at the time of virus spread should be reconsidered.If infection pressures in different areas or successive years are to be compared, the tobacco test should be standardized. A proposal to this effect is made.Samenvatting In Swifterbant (Oostelijk Flevoland) werd de infectie met het aardappel-Y^N-virus (PVY^N) bepaald met behulp van de tabakstoests. In percelen met bieten, tarwe en pootaardappelen bleek de infectie hetzelfde verloop te hebben. Tussen het infectieverloop van PVY^N in de rand en in het midden van een veld consumptieaardappelen werd eveneens geen verschil gevonden. Wel was de infectiedruk hier duidelijk hoger dan in het pootgoedperceel. Een barrier crop van 10 rijen tarwe verminderde de infectiedruk niet.De volgende conclusies kunnen worden getrokken. Aardappelopslag buiten en in aardappelvelden vormt een zeer belangrijke infectiebron. Zowel in 1976 als in 1977 vond de virusverspreiding plaats vóór de vlucht vanMyzus persicae begon, zoals deze werd bepaald met behulp van de gele Moericke vangbakken. Het effect van opzuiveren ten tijde van de virusverspreiding dient aan een nader onderzoek te worden onderworpen. De infectiedruk kan met de tabakstoets op meer directe wijze worden vastgesteld dan met bladluisvangsten mogelijk is.Wil men overgaan tot het vergelijken van de infectiedruk in verschillende gebieden of in verschillende jaren, dan dient de tabakstoets te worden gestandaardiseerd. Een voorstel hiertoe wordt gedaan.