不同浓度CO2对玉簪试管苗光合蒸腾及气孔导度的影响

在其他环境条件完全相同的情况下，升高ＣＯ２浓度可显提高玉簪试管苗的净光合速率ＣＯ２浓度与光合速率存在正相关关系。ＣＯ２浓度变化与玉簪试管苗的蒸腾速率没有显相关关系，即其蒸腾速率不随其ＣＯ２浓度变化而有效显变化，只有在ＣＯ２浓度高于１２００Ｖｍｏｌ·ｍｏｌ＾－１时，才出现蒸腾速率明显下降趋势。     

冬春棚室蔬菜CO2气肥的综合调控技术

ＣＯ２是作物光合作用的主要原料，而冬春棚室蔬菜生产需在密闭的状态下进行，致使棚内ＣＯ２匮乏，既影响产量，又降低了产品质量。因此，抓好冬春棚室蔬菜ＣＯ２气肥的调控，是一项投资少、见效快、效益高的实用新技术。 一、施放ＣＯ２气肥的作用 １．增声棚室蔬菜生长期所需ＣＯ２浓度一般为１０００×１０－６，而在日出后闭棚条件下ＣＯ２浓度则为８５×１０－６～２００×１０－６。在此浓度下作物每天忍受１ｈ，７天后则表现根弱、苗瘦、花芽分化减弱。此时追施ＣＯ２气肥，可使作物生长健壮，叶绿素增加，雌花增多，果位低。一般茄…     

保护地蔬菜CO2施肥技术

保护地蔬菜ＣＯ_２施肥技术张树学大量科研试验证明空气中３００（１０－６）的ＣＯ２远不能满足黄瓜、番茄、辣椒等蔬菜光合的需要，保护地内人工补施ＣＯ２有明显的增产作用，尤其是早期产量增产幅度更大，同时还可增强植株抗性，我们通过试验，采用化学反应法产生ＣＯ?..     

贵州山茶属五种野生植物的光合特性研究

研究了小黄花茶（ＣａｍｅｌｌｉａｌｕｔｅｏｆｌｏｒａＹ．Ｋ．Ｌｉ）、美丽红山茶（Ｃ．ｄｅｌｉｃａｔａＹ．Ｋ．Ｌｉ），威宁短柱油茶（Ｃ．ｓａｌｅｎｅｎｓｉｓＳｔａｐｆｅｘＢｅａｕ．）、狭叶瘤果茶（Ｃ．ｎｅｒｉｉｆｏｌｉａＣｈａｎｇ）和四球茶（Ｃ．ｔａｃｈａｎｇｅｎｓｉｓＦ．Ｓ．Ｚｈａｎｌｇ）贵州山茶属五种野生植物的光合生理，均为Ｃ３植物，其ＣＯ２补偿点在６０μＬ／Ｌ左右，光呼吸速率与总光合的比值为２５％左右，光补偿点８００～２５００ｌｘ，光饱和点１６００～４１０００ｌｘ。其中小黄花茶的光补偿点及光饱和点最低，威宁短柱油茶的光补偿点及光饱和点最高；净光合速率（Ｐｎ）６．００～１５．００ＣＯ２ｍｇ／（ｄｍ２·ｈ），光呼吸速率（Ｐｒ）２．００～５．００ＣＯ２ｍｇ／（ｄｍ２·ｈ），其中威宁短柱油茶的Ｐｎ及Ｐｒ均较高，四球茶的Ｐｎ及Ｐｒ均较低；Ｄｒ（暗呼吸速率）０．７０～２．６０ＣＯ２ｍｇ／（ｄｍ２·ｈ），其中威宁短柱油茶的Ｄｒ较高，小黄花茶的Ｄｒ较低。Ｐｎ、Ｐｒ及Ｄｒ相互间呈正相关；Ｃｈｌ．（ａ＋ｂ）（叶绿素）含量７．６０～１２．５０ｍｇ／ｄｍ２，其中小黄花茶的含量较高，威宁短柱油茶的含量较低。     

生姜群体光台特性的研究

利用田间同化箱对生姜的群体光合特性进行了研究。结果表明，生姜群体光合速率（ＣＰｎ）有明显的季节变化和日变化，随着季节的进展ＣＰｎ呈二次曲线型。ＣＰｎ的日变化呈单峰曲线，峰值出现在中午１２时左右。ＣＰｎ的峰值与旺盛生长季节相吻合。在本试验范围内单位土地面积的ＣＰｎ随ＬＡＩ的增加而增加，若以叶面积计算ＣＰｎ则随叶面积指数（ＬＡＩ）的增加而降低。在田间试验条件下ＣＰｎ随光强和ＣＯ２浓度的增加而增加，在自然光下未测到生姜ＣＰｎ的光饱和点。     

大白菜对CO_2浓度倍增的生理生态反应

利用半封闭式同化箱研究在７００、５００、３５０μＬ／ＬＣＯ２浓度条件下大白菜莲座期生长性状和生理特性的不同反应。结果表明，提高ＣＯ２浓度，可促进白菜光合作用，延长光合时间，降低光补偿点。与３５０μＬ／Ｌ相比，７００和５００μＬ／Ｌ光合速率增加６８％和３９％，光合时间延长５５和２５分钟。同时，ＣＯ２浓度增高，减小了气孔导度，叶温升高，蒸腾系数减弱，从而提高了水分利用率。７００和５００比３５０μＬ／Ｌ叶温分别增加０．５℃和０．１３℃，蒸腾系数降低２７．１％和２３．１％，叶面积增长８６．４％和７９．１％，叶片数增加８０．７％和４０．９％．鲜重增加７６．１％和５２．９％，干重增加３１．０％和２８．２％。     

节能日光温室CO2的施用

节能日光温室ＣＯ_２的施用亢立，董晓飞二氧化碳（ＣＯ２）是绿色植物进行光合作用的重要原料之一，具有其它任何物质都不可代替的作用，被称之为蔬菜的“粮食”。日光温室中光照弱、湿度大、气流缓慢，ＣＯ２不能从大气中任意补充，ＣＯ２的不足是目前日光温室蔬菜增产...     

大型温室内二氧化碳消长规律的观察

为了探索积累设施园艺现代化的经验，江苏省农林厅、南京市蔬菜研究所引进了一套荷兰大型电脑自控温室，温室净面积２９１８ｍ２，其内部通风、降温、供热、揭盖多重幕、灌溉、施肥均由电脑系统自动控制，但是没有ＣＯ２控制系统，因此，本试验的目的是研究在正常栽培园艺作物情况下，温室内ＣＯ２消长情况，为ＣＯ２控制系统的建立和ＣＯ２施肥提供理论依据。 材料和方法 试验于１９８８年１～２月在引进的荷兰温室中进行，主栽作物为番茄（包括无土栽培与有土栽培两部分）。 ＣＯ２测定用江都分析仪器厂生产的ＣＯ２测定仪（测定范围为０…     

蔬菜施用化肥量的简化计算及实例

蔬菜作物种类繁多，需肥特点差异很大，种植面积相对较小，测土配方施肥具体应用很困难，而对菜农而言掌握一定的化肥施用量又很有必要，根据我区土壤及肥料特点，下面我们介绍一种简单的计算方法。首先应了解施肥量的计算公式Ｙ（施肥量）＝〔（１－ｂ／ａ）〕×Ｘ。Ｙ为应施肥料量，ｂ为土壤供给率，ａ为化肥利用率，Ｘ为预计产量的元素总量。除Ｙ外其余我们皆称为参数。１　Ｘ参数：这个参数是由预计产量与单位产量元素吸收量相乘得到（表１）。　　表１主要蔬菜元素吸收量※蔬菜种类ＮＰ２Ｏ５Ｋ２ＯＣａＭｇ番　茄２．７０．７５．１２…     

气调贮藏对鸭梨果心褐变的影响

鸭梨采收后采用逐渐降温的方法，经３０天的时间将贮藏温度从１００Ｃ降至００Ｃ，然后采用ＣＡ和ＭＡ处理。实验结果表明：在Ｏ２浓度不低于１６％的前提下，鸭梨果实可长期耐受３％的ＣＯ２而不至造成高ＣＯ２伤害，当ＣＯ２浓度高于７％时，经１５０天贮藏的果实果心褐变率高达８６％。在ＣＯ２浓度较高时，细胞膜透性明显增强，游离态多酚氧化酶活性增强，导致果心褐变大量发生。     

Relationship between renal hypertension and cardiac α1-adrenoceptor autoantibodies in rats

AIM: To examine the autoantibody against α₁-adrenoceptor and its biologic activities during the development of renal hypertension. METHODS: Renal hypertension of rat was achieved by clipped renal artery, the titre of autoantibody to α₁-adrenoceptor was detected using ELISA immunoassay. Furthermore, the biological offects of these autoantibodies on cultured cardiomyocytes were also examined. RESULTS: After two weeks of clipping renal arteries, both the frequency of occurrence and the titre of autoantibodies to cardiac α₁-adrenergic receptor were significantly increased as compared with the control of pre-treatment. The increased autoantibodies lasted for several weeks and then automatically decreased gradually to the pre-clipping level at 12 weeks. The biological effects of these autoantibodies displayed an "agonistic-like" activities on the beating frequency of cultured neonatal cardiomyocytes. CONCLUSION: Autoantibodies against α₁-adrenoceptor may play a role in the elevation of peripheral vascular resistance and in the development of cardiac hypertrophy in rats with renal hypertension.     

Influence of Mineral Nutrients on Strawberry Fruit Quality and Their Accumulation in Plant Organs

Abstract

This review is based partly on complete articles and partly on abstracts. Three of the 60 articles deal with the total uptake of elements in strawberry plant organs in two different strawberry production systems, both considered as optimal concerning amount and balance of elements. The effect on fruit quality may be dramatic if the level of a particular element is outside this range, but there may also be effects initiated by differences within the optimal range of elements. Most articles refer to product oriented quality, but some focus on consumer oriented quality, as discussed by Shewfelt (1999). The discussion here is on a general basis, so one should keep in mind that there are cultivar differences and that specification of nutrition ideally should mirror the needs of a single cultivar, or a group of cultivars with similar requirements. Also, to get a complete understanding of the subject future reviews should embrace a broader access of information including the effect on plant development of individual elements, such as the role of calcium in fruit firmness and its importance in cell wall structure. However, the intention here is to narrow the information to results that suggest a direct connection between nutrient uptake and fruit quality.     

辣椒素积累生理研究的最新进展

辣椒素的积累主要受到遗传、环境、竞争物质、酶的影响.在遗传方面,辣椒的基因型以及决定辣椒素含量的特定基因对辣椒素的积累起着决定作用,环境中的光照、温度、CO2、肥料起辅助作用,竞争物质,如木质素、类黄酮、蛋白质、单宁、生物碱、香豆素等物质与辣椒素的积累相互抑制,辣椒素的合成酶和降解酶同样影响辣椒素的积累.     

Mixed-severity fire regime in a high-elevation forest of Grand Canyon,Arizona, USA

Fire regime characteristics of high-elevation forests on the North Rim of the Grand Canyon, Arizona, were reconstructed from fire scar analysis, remote sensing, tree age, and forest structure measurements, a first attempt at detailed reconstruction of the transition from surface to stand-replacing fire patterns in the Southwest. Tree densities and fire-/non-fire-initiated groups were highly mixed over the landscape, so distinct fire-created stands could not be delineated from satellite imagery or the oldest available aerial photos. Surface fires were common from 1700 to 1879 in the 4,400 ha site, especially on S and W aspects. Fire dates frequently coincided with fire dates measured at study sites at lower elevation, suggesting that pre-1880 fire sizes may have been very large. Large fires, those scarring 25% or more of the sample trees, were relatively infrequent, averaging 31 years between burns. Four of the five major regional fire years occurred in the 1700s, followed by a 94-year gap until 1879. Fires typically occurred in significantly dry years (Palmer Drought Stress Index), with severe drought in major regional fire years. Currently the forest is predominantly spruce-fir, mixed conifer, and aspen. In contrast, dendroecological reconstruction of past forest structure showed that the forest in 1880 was very open, corresponding closely with historical (1910) accounts of severe fires leaving partially denuded landscapes. Age structure and species composition were used to classify sampling points into fire-initiated and non-fire-initiated groups. Tree groups on nearly 60% of the plots were fire-initiated; the oldest such groups appeared to have originated after severe fires in 1782 or 1785. In 1880, all fire-initiated groups were less than 100 years old and nearly 25% of the groups were less than 20 years old. Non-fire-initiated groups were significantly older (oldest 262 years in 1880), dominated by ponderosa pine, Douglas-fir, or white fir, and occurred preferentially on S and W slopes. The mixed-severity fire regime, transitioning from lower-elevation surface fires to mixed surface and stand-replacing fire at higher elevations, appeared not to have been stable over the temporal and spatial scales of this study. Information about historical fire regime and forest structure is valuable for managers but the information is probably less specific and stable for high-elevation forests than for low-elevation ponderosa pine forests.This revised version was published online in May 2005 with corrections to the Cover Date.     

瓜叶绿素降解关键酶基因PPH和PAO cDNA片段的克隆与表达初步分析

 以西双版纳黄瓜和‘华黄5号’黄瓜叶片为试验材料,研究了衰老过程中两种黄瓜叶片叶绿素含量变化及脱镁叶绿素脱镁叶绿酸水解酶基因PPH和脱镁叶绿酸a加氧酶基因PAO的表达。结果表明：随着叶片衰老,叶绿素a和叶绿素b含量显著降低,叶绿素a与叶绿素b的比值在0.5左右,推测叶绿素b的含量可能对黄瓜叶片保绿起到重要作用。荧光定量RT-PCR分析结果显示：PPH和PAO在西双版纳黄瓜叶片生长35 d时表达量最高,分别为5.50和1.86;PPH在‘华黄5号’叶片35 d时表达量最高,为7.14,而PAO在35和45 d表达量都很高,分别为3.90和3.91;PPH和PAO在西双版纳黄瓜叶片中的表达量低于在‘华黄5号’中。     

Effects of simvastatin on PDGF-BB and serum-induced proliferation of vascular smooth muscle cells and on the expression of tumor suppressor gene PTEN

AIM:To observe the effect of simvastatin on the proliferation of vascular smooth muscle cells(VSMCs) induced by serum and growth factor PDGF-BB and the effect of simvastatin on the expression of PTEN,a important regulator of G₁/S cell cycle transition. METHODS:The DNA synthesis was determined by [³H]-TdR incorporation, cell cycle was examined with flow cytometry, the protein level of PTEN was measured by Western blot method. RESULTS: (1)Simvastatin inhibited [³H]-TdR incorporation in a dose dependent manner. (2) Flow cytometric DNA analysis revealed that simvastatin induced significantly enhancement of G₀/G₁ phase and decrease in S phase VSMCs.(3)Simvastatin increased protein level of PTEN and mevalonate, a metabolite of HMG-COA, reversed the effect of simvastatin on PTEN protein expression. CONCLUSION:Simvastatin may inhibit proliferation of VSMCs and retarded cell cycle in G₀/G₁ phase by increasing PTEN expression through inhibiting synthesis of mevalonate.     

微波消解ICP—MS法测定香菇中重金属含量

采用密闭微波消解法消解香菇样品,在优化微波消解条件的基础上,建立微波消解ICP—MS法同时测定千香菇中As、PI）、Cd、Cr、Cu、Zn、Mn、Fe和Mg九种重金属元素的方法,在最佳试验条件下,加标收率为92．0％～104．6％,RSD为2．2％-5．3％。该方法简便、快速、准确：     

Relationships of landscape,prey and agronomic variables to the abundance of generalist predators in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis>) fields

A two-year field study investigated the possible effects of grain sorghum (Sorghum bicolor [L.] Moench) and uncultivated areas on the abundance of generalist predators in commercially-managed cotton (Gossypium hirsutum L.) fields in Texas, USA. From 63 to 70 fields were sampled for pests and predators over nine consecutive weeks during early stages of cotton development. Additional data on agronomic practices and landscape composition at three spatial scales were also collected for each field. Stepwise regression analyses were used to determine the relationships of landscape, agronomic and prey variables to the abundance of generalist predators. Because the variables most closely linked to predator levels could vary over time, separate regressions were conducted for three time periods corresponding to stages of grain sorghum growth (half-bloom, hard-dough, maturity) in each year. Significant relationships between predator abundance and agricultural landscape composition appear in both years and in all three time periods, but the specific relationships of landscape variables to cotton predator levels differed between and within years. At maturity in 2001, predator levels rose as the amount of uncultivated land from 1.6 to 3.2 km distant and the perimeter shared with grain sorghum increased. During 2002, the area of grain sorghum (half-bloom) and uncultivated land (hard-dough) within 1.6 km of cotton fields were both positively related to predator numbers. Cotton planting dates and the abundance of cotton fleahoppers (Pseudatomoscelis seriatus [Reuter]) were also strongly linked to predator numbers during both years. Results suggest that the total amount of grain sorghum or uncultivated land in an area is more important than the presence of these habitats adjacent to cotton fields, and that landscape composition may sometimes be the most important factor in determining predator abundance.     

Inferring the effects of landscape structure on roe deer (Capreolus capreolus) movements using a step selection function

In this study, we sought to understand how landscape structure affects roe deer movements within their home-range in a heterogeneous and fragmented agricultural system of south-western France. We analysed the movements of 20 roe deer fitted with GPS collars which recorded their locations every 2–6 h over several months (mean = 9 months). Based on empirical observations and previous studies of roe deer habitat use, we hypothesised that roe deer should avoid buildings and roads, move preferentially along valley bottoms and through the more wooded areas of the landscape. To test these hypotheses we paired each observed movement step with 10 random ones. Using conditional logistic regression, we modelled a step selection function, which represents the probability of selecting a given step as a function of these landscape variables. The selected model indicated that movements were influenced by all the tested landscape features, but not always in the predicted direction: our results suggested that roe deer tend to avoid buildings, roads, valley bottoms and possibly the more wooded areas (although the latter result should be interpreted with caution, as it may be influenced by a bias in the rate of GPS fix acquisition in woods). The distances to buildings and to roads were the most influential variables in the model, suggesting that the avoidance of potential sources of disturbance may be a key factor in determining ranging behaviour of roe deer in human dominated landscapes.     

Inoculation of growing media with the rhizobacterium Variovorax paradoxus 5C-2 reduces unwanted stress responses in hardy ornamental species

Inoculation of growing media with plant growth promoting rhizobacteria (PGPR) has a number of potential benefits for the production of ornamental plants. Certain rhizobacteria synthesise the enzyme ACC deaminase, which cleaves ACC, the precursor of the plant hormone ethylene. Bacterial metabolism is now known to lead to a reduction in [ACC] in the plant transpiration stream and bacteria are hypothesised to act on ACC exuded from roots. This in turn reduces the ethylene generated in plants growing in growing media inoculated with these bacteria. Here we tested if applications of the ACC deaminase containing rhizobacteria Variovorax paradoxus⁵C–²could be of benefit to ornamental growers by reducing ethylene generation in stressed plants. Ethylene is produced at levels that are inhibitory to growth and development under a number of abiotic stresses. The propagation and production of hardy ornamentals is deleteriously affected by abiotic stresses that involve ethylene signalling, including drought and physical wounding. Inoculation of growing media with V. paradoxus 5C-2 lowered ethylene emission from mature leaves of Cytisus × praecox experiencing drought stress. In addition, bacterial inoculation of the growing media resulted in significantly reduced abscission of the mature leaves under drought treatment. Beneficial effects of inoculation where also found in the wounding response of Fargesia murielae following divisional propagation and late season senescence in Aquilegia × hybrida in response to drought stress. Together these results demonstrate that V. paradoxus⁵C–²has real potential for use on ornamental nurseries in situations where plant stresses are unavoidable.