Spur behaviour in almond trees: relationships between previous year spur leaf area, fruit bearing and mortality

In mature almond (Prunus dulcis) orchards, the majority of crop is borne on spurs (short, proleptic shoots) that can live for several years and can produce from one to five fruits. Previous research has led to the hypothesis that spur longevity is related to spur light exposure, cropping and age. However, limited quantitative data are available to substantiate these hypotheses. The objective of this study was to determine spur characteristics that were most highly correlated with spur productivity and longevity in mature, bearing almond trees. Previous year spur leaf area was strongly related to spur viability and flowering; the greater the leaf area in the previous year, the higher the probability of spur survival into the next year and the higher the probability for the spur to bear one or more flowers. Previous year bearing also appeared to influence viability and return bloom, especially in spurs with low leaf area. These results suggest that spur source-sink balance is basic to the life cycle of almond spurs. Furthermore, the results are consistent with the hypothesis that spurs are semi-autonomous organs with respect to carbohydrate balance for much of the growing season. Finally, this information provides general thresholds for maintaining spur viability and productivity that will be useful for developing and evaluating tree training systems and orchard management practices.     

提高李子座果率的几点技术措施

李子在双辽地区座果率极低,只有0.1%左右.通过合理修剪、加强肥水管理和病虫害防治等措施,可以显著提高座果率,盛果期平均每株树产量为26.0 kg以上.     

Water stress and crop load effects on fruit fresh and dry weights in peach (Prunus persica)

Effects of water stress on fruit fresh and dry weights were investigated in peach trees, Prunus persica (L.) Batsch., with varying crop loads: light, moderate and heavy. In well-watered controls, tree water status was independent of crop load. In trees receiving reduced irrigation, the degree of water stress increased with increasing crop load. Water stress induced fruit fresh weight reductions at all crop loads. Fruit dry weight was not reduced by water stress in trees having light to moderate crop loads, indicating that the degree of water stress imposed did not affect the dry weight sink strength of fruit. Water-stressed trees with heavy crop loads had significantly reduced fruit dry weights, which were likely due to carbohydrate source limitations resulting from large crop carbon demands and water stress limitations on photosynthesis.     

Relationships between nutrient composition of flowers and fruit quality in orange trees grown in calcareous soil

To determine if flower nutrient composition can be used to predict fruit quality, a field experiment was conducted over three seasons (1996-1999) in a commercial orange orchard (Citrus sinensis (L.) Osbeck cv. 'Valencia Late', budded on Troyer citrange rootstock) established on a calcareous soil in southern Portugal. Flowers were collected from 20 trees during full bloom in April and their nutrient composition determined, and fruits were harvested the following March and their quality evaluated. Patterns of covariation in flower nutrient concentrations and in fruit quality variables were evaluated by principal component analysis. Regression models relating fruit quality variables to flower nutrient composition were developed by stepwise selection procedures. The predictive power of the regression models was evaluated with an independent data set. Nutrient composition of flowers at full bloom could be used to predict the fruit quality variables fresh fruit mass and maturation index in the following year. Magnesium, Ca and Zn concentrations measured in flowers were related to fruit fresh mass estimations and N, P, Mg and Fe concentrations were related to fruit maturation index. We also established reference values for the nutrient composition of flowers based on measurements made in trees that produced large (> 76 mm in diameter) fruit.     

新疆扁桃结实率低的生理与分子机制

为给生产上提高扁桃产量和品质而制订科学的栽培管理措施提供理论依据,针对新疆扁桃结实率低的问题,就扁桃的花芽分化、授粉受精、坐果和幼果发育的生物学特性及树体营养、激素等相关影响因素进行了3个国家自然科学基金项目的研究,结果基本摸清了新疆扁桃受精不亲和的生物学特性和分子机理及结实率低的生理机制;通过对新疆扁桃不同品种、类型...     

坝上地区大果欧李温室栽培技术与开发利用

##正##1栽培技术1.1栽培方式温室内多采用高垄或高畦栽培,选择土质疏松、透气性好,尤以深厚砂质壤土为佳,阳光充足地块,优点是抬高了树体,方便于管理,改善了通风透光条件,易于排水,且地温提升较快,有利于根系生长。一般高垄栽培时垄高20~30cm,高畦栽培时畦高30~40cm。株行距40cm×80cm或40cm×50cm均可。定植行向为南北向。合理的密度能达到温室土地利用最大化,但同时对管理的精度有了更高的要求。     

单瓣榆叶梅果实与种子性状的研究

以单瓣榆叶梅果实与种子为材料,观测种实有关性状,结果表明:果实形成初始阶段发育较快,花后第3 d幼果为绿豆粒大小,第7 d如黄豆粒大小。果实成熟时有3种果形,即近圆形果实、扁圆形果实和阔纺锤形果实,3种果实平均纵向径、横向经大小分别为1.7 cm与1.6 cm、1.7 cm与1.8 cm、2.1 cm与1.8 cm,阔纺锤形果实最大,3种果形脱出的种子纵向径、宽横向径、窄横向径分别为1.3 cm、1.0 cm、0.9 cm,1.3 cm、1.1 cm、1.0 cm,1.6 cm、1.2 cm、1.1 cm。外种皮均为黄褐色,形状均为阔扁纺锤形。3种果形种子千粒重均值变化范围在46~61 g,阔纺锤形果实种子千粒重为其他两种果实的1.30倍和0.32倍,差异显著。     

Relationships between nutrient supply, nitrogen partitioning and growth in young Sitka spruce (Picea sitchensis)

Budget studies have shown that internal cycling may contribute a large proportion of the annual nutrient supply required to support new growth in trees. Use of budgets to quantify internal cycling only quantifies the net transfer of nutrients within the plant. Differential partitioning of remobilized nutrients and current nutrient uptake could lead to errors in the interpretation of results from these studies. We have quantified the dynamic relationships among tree growth, nutrient uptake and internal cycling by labeling the current uptake of N in trees that received contrasting amounts of nutrient. Two-year-old seedlings of Sitka spruce (Picea sitchensis (Bong.) Carr.) were grown in sand culture in a greenhouse for one year. The trees received nutrients in a balanced solution at either a high (high-RAR) or a low (low-RAR) relative addition rate throughout the experiment. Current N uptake was labeled with (15)N from April 13 to July 25. Thereafter, trees were re-potted in clean sand and unlabeled N applied until November 13. Overall growth was sustained for approximately 10 weeks before treatment effects were observed. Initially, no differences in the partition of growth or remobilized N occurred, although partition of current uptake favored the roots of plants in the low-RAR treatment. After 6 weeks, the partition of both growth and remobilized N altered in favor of roots of plants in the low-RAR treatment. Nutrient supply had no effect on the amount or rate of N remobilization. No evidence was found to suggest that N taken up in the current season and partitioned to preexisting shoots or roots is remobilized late in the season to support growth of new shoots. However, some trees in the high-RAR treatment exhibited a second flush of growth later in the season that was partially sustained by remobilization of (15)N from current shoots formed earlier in the season. Use of (15)N demonstrated differential partitioning of current uptake and remobilized N. The results highlight the limitations of simple budget studies for quantifying internal cycling.     

桃水孔蛋白基因克隆及序列分析

为给水孔蛋白(AQP)在低温对花芽发育和休眠调控中的作用研究奠定基础,以低温休眠的桃"满天红"花芽为试材,提取总RNA,根据其它植物AQP基因保守区设计简并引物,采用RT-PCR方法,扩增出3个编码长约147个氨基酸序列的水孔蛋白基因PpPIP1-1、PpPIP1-2和PpPIP2-1。同源性比对结果表明这些序列与其它物种AQP基因具有较高的同源性。这3个AQP基因的氨基酸序列均具有MIP家族的特征信号序列SGXHXNPAVT,还具有植物质膜水孔蛋白(PIP)家族的特征信号序列GGGANXXXXGY和TGI/TNPARSL/FGAAI/VI/VF/YN。经系统发育分析将这3个AQP基因分为2类,分属PIP蛋白的PIP1和PIP2亚家族成员。     

青梅果疮痂病的研究初报

青梅 ( Prunus mume)是我国南方特产经济树种 ,有很高的营养价值、药用价值和经济价值。青梅在广东省主要分布在普宁、惠州等地。近年来 ,梅果一直是广东出口创汇的主要水果之一。由于病菌的侵染 ,使梅果常常产生不正常的病斑 ,严重影响了梅果的品质和销售价格。经对病果进行分离培养鉴定结果属于疮痂病( Cladosporium carpophilum)。对该病的研究已有报道。我们于 1998～ 1999年着重调查研究了该病的发生规律 ,旨在掌握制约病害发生和发展的主要因子 ,以期为有效防治这种病害提供科学依据。1　材料与方法1.1　试验地概况试验地位于广东惠…     

辽西地区山杏开花及坐果习性研究

通过对山杏开花、坐果习性及其影响因子研究,认为南坡花期早,坐果率高;北坡花期晚,坐果率低;从萌动期到始花期所需的生物学有效积温为82.83℃;光照强度是促进雌蕊发育的主导气象因子;坐果率与日均温的相关性最大。在各类果枝中,花和幼果主要着生在花束状果枝和短果枝上,为了提高坐果率,应注重对花束状果枝和短果枝的培养。     

山茱萸早实丰产试验研究

对山茱萸幼树速生丰产栽培技术进行了初步探讨。3a试验结果表明，通过施肥、环切、环剥、夏剪、开张主枝等措施，使山茱萸幼树栽后4a成花，5a结果，6a丰产，平均株产鲜果1150g，达到较高的生产水平。试验还对不同的环切，不同环切与开张主枝相结合，环剥、夏剪、开张主枝措施对山茱萸幼树成花和结果的影响进行了比较。提出了适宜的速生丰产栽培技术措施，对产区山茱萸幼树栽培具有重要指导意义。     

果梅品种分类研究进展

梅是原产我国的重要园艺植物。果梅分类一直是梅种质资源研究的重要内容,也是梅品种资源利用的科学依据。长期以来,果梅品种分类深受果树学者的重视并取得了可喜的研究进展与突破。该文就梅的植物学分类与梅花品种分类系统、果梅品种分类的意义、果梅品种分类（包括园艺学、孢子学、细胞学、数值、同工酶、分子生物学分类）研究进行了系统地总结与归纳,同时对果梅品种分类研究存在的问题提出了一些新见解。     

Relationships between climate and radial growth in black pine (Pinus nigra Arnold ssp. salzmannii (Dunal) Franco) from the south of France

? Context

The Salzmann pine (Pinus nigra ssp. salzmannii) is an endemic subspecies of black pine native to the Western Mediterranean basin. In Spain, Salzmann pine covers extensive areas (approx. 350 000?ha), while in France where few scattered populations subsist, its distribution area is estimated at approx. 3 000?ha.

? Method

We used a dendroecological approach to understand the impact of climate fluctuations on Salzmann pine from France. Spatial and temporal variability of radial growth response was compared in three ecologically different populations (Conflent, Gorges du Tarn, Saint-Guilhem-le-D??sert).

? Results

The Conflent population showed a strong sensitivity to spring precipitation deficits (March to June), while at Gorges du Tarn and Saint-Guilhem sites, autumn (October) of the previous year and winter (February) temperatures explained more variance than precipitations and were, respectively, negatively and positively correlated to radial growth.

? Conclusion

Although covering a limited distribution range in France, Salzmann pine demonstrated large differences in radial growth response to climate and soil variations.     

营养与衰老关系研究

指出了营养是人在整个生命过程中保持和提高健康状况的重要因素之一,营养的改善有助于降低慢性疾病的患病风险和延长寿命。研究发现卡路里限制能够延长一些生物的寿命,延迟衰老特征的产生,卡路里限制是通过调节表观遗传、细胞生长、衰老信号及细胞间传递信号分子来诱导细胞和整个机体水平上的衰老应答。适应性衰老应答可以使细胞和机体抗年龄有关的机体变化促进长寿。在人体中,卡路里限制能够抵抗癌症、糖尿病、动脉粥样硬化、心血管病和神经组织退化等慢性疾病的发生与发展从而促进人类的长寿。     

Crop load and water stress effects on daily stem growth in peach (Prunus persica)

We investigated crop load and water stress effects on diurnal stem extension growth of field-grown peach (Prunus persica (L.) Batsch) trees. Neither the presence of fruit nor reduced irrigation significantly altered the timing of diurnal fluctuations in stem growth rate. Stems with subtending fruit had significantly reduced growth compared to stems with no subtending fruit. Crop load had no significant effect on relative stem extension rates and the majority of the reduction in absolute growth was the result of a smaller zone of elongation in fruit-bearing stems than in stems with no subtending fruit. Fruit removal did not increase growth rates within 24 h. When irrigation was reduced, the length of the stem elongation zone and total daily stem growth were significantly decreased relative to well-irrigated controls and the decreases were highly correlated with stem water potential. Compared with well-irrigated controls, relative stem extension rates of water-stressed trees were reduced at several times during the 24-h period, but the degree of reduction was not proportional to the difference in stem water potentials between the treatments.     

西部沙樱、欧李苗期耐旱性研究

通过对西部沙樱和欧李幼苗进行干旱胁迫,采用隶属函数法对其净光合速率、相对电导率以及叶绿素含量等耐旱性指标进行综合评定。结论认为,西部沙樱的耐旱能力强于欧李。     

山杏、山樱桃种源试验初步研究

2004-2006年,对山杏、山樱桃进行种源试验,结果表明:山杏敖汉旗等4个种源苗期生长量存在极显著差异,敖汉旗和巴林右旗种源高生长、速生性、苗木形态及整齐度等明显优于万家沟和乌拉山种源。造林初期山杏树高、地径、冠幅等性状差异明显,广义遗传力较大,种源间遗传变异丰富。种源排序为敖汉旗>巴林右旗>乌拉山>万家沟。初步选择敖汉旗为优良种源。山樱桃西苏旗种源苗期高生长、地径生长等明显超过其他3个种源,造林试验表现优秀。固阳种源次之,该种源生物量较高。万家沟和凉城种源生长量、适应性和抗性等都表现较差。西苏旗种源为优良种源。     

施肥对红松无性系种子园母树结实效应研究

通过在红松无性系幼龄种子园进行的氮肥、磷肥和钾肥3种肥料,每种肥料设置4个水平的施肥试验,研究分析了氮肥、磷肥和钾肥3种肥料,以及每种肥料的不同施用数量,对促进红松无性系种子园幼龄母树结实的效果,提出促进红松无性系幼龄植株结实的适宜施肥数量。