Modeling effects of weather and source-sink relationships on mango fruit growth

We modeled the effects of weather and source-sink factors on mango fruit growth. The peach fruit-growth model "Cashoo" was adapted for mango fruit. The model accounts for the main processes of fruit growth, i.e., leaf photosynthesis, fruit demand, fruit respiration, and storage and mobilization of leaf and stem reserves. Simulations for three successive years and for various leaf-to-fruit ratio treatments showed good agreement with observed fruit growth data. Simulations of fruit growth under different climatic conditions, especially with contrasting temperature and radiation, and for different values of initial fruit dry mass and leaf-to-fruit ratio, showed that variations in fruit growth among years can be partly explained by climatic variations through their effects on leaf photosynthesis, fruit demand and fruit growth rate. However, climatic changes contribute substantially less to observed variability in fruit growth than to initial fruit dry mass and leaf-to-fruit ratio.     

A biochemical model of photosynthesis for mango leaves: evidence for the effect of fruit on photosynthetic capacity of nearby leaves

Variations in leaf nitrogen concentration per unit mass (Nm) and per unit area (Na), mass-to-area ratio (Ma), total nonstructural carbohydrates (Ta), and photosynthetic capacity (maximum carboxylation rate, electron transport capacity, rate of phosphate release in triose phosphate utilization and dark respiration rate) were studied within the digitized crowns of two 3-year-old mango trees (Mangifera indica L.) on La Réunion Island. Additional measurements of Nm, Na, Ma, Ta and photosynthetic capacities were performed on young, fully expanded leaves of 11-year-old mango trees. Leaves of similar gap fractions were taken far from and close to developing fruits. Unlike Nm, both Na and Ta were linearly correlated to gap fraction. Similar relationships were found for all leaves whatever their age and origin, except for Ta, for which we found a significant tree effect. Photosynthetic capacity was nonlinearly correlated to Na, and a unique relationship was obtained for all types of leaves. Photosynthetic acclimation to light was mainly driven by changes in Ma, but allocation of total leaf N between the different photosynthetic functions also played a substantial role in acclimation to the lowest irradiances. Leaves close to developing fruits exhibited a higher photosynthetic capacity than other leaves, but similar Ta. Our data suggest that Ta does not control photosynthetic capacity in mango leaves. We used the data to parameterize a biochemically based model of photosynthesis and an empirical stomatal conductance model, allowing accurate predictions of net photosynthesis of leaves in field-grown mango trees.     

冬季与早春低温对京桃开花与生长的影响

以长春市街路、庭院栽植的京桃为材料,观测2009～2010年冬春季节持续低温对其开花与生长的影响,结果表明:成年大树的开花与生长受到严重影响,所有植株均未开花,受害率达到100%;部分植株发生了不同程度的枯死枝和整株死亡现象,平均死亡率为11.1%.冬春季节的持续低温是导致受冻害的主要因素,可使花芽受冻致死和大树死亡;...     

果树光合作用研究进展

综述了近年来国内外果树光合作用的研究进展。涉及的内容有：果树光合作用的基本特性;影响果树光合作用的内外因素;果树光合作用的测定方法,简述了叶绿素荧光动力学技术。     

An analysis of elastic and plastic fruit growth of mango in response to various assimilate supplies

Changes in elastic and plastic components of mango (Mangifera indica L. cv 'Cogshall') fruit growth were analyzed with a model of fruit growth over time and in response to various assimilate supplies. The model is based on water relations (water potential and osmotic and turgor pressures) at the fruit level. Variation in elastic fruit growth was modeled as a function of the elastic modulus and variation in turgor pressure. Variation in plastic fruit growth was modeled using the Lockhart (1965) equation. In this model, plastic growth parameters (yield threshold pressure and cell wall extensibility) varied during fruit growth. Outputs of the model were diurnal and seasonal fruit growth, and fruit turgor pressure. These variables were simulated with good accuracy by the model, particularly the observed increase in fruit size with increasing availability of assimilate supply. Shrinkage was sensitive to the surface conductance of fruit peel, the elasticity modulus and the hydraulic conductivity of fruit, whereas fruit growth rate was highly sensitive to parameters linked to changes in wall extensibility and yield threshold pressure, regardless of the assimilate supply. According to the model, plastic growth was generally zero during the day and shrinkage and swelling were linked to the elastic behavior of the fruit. During the night, plastic and elastic growths were positive, resulting in fruit expansion.     

油菜素内酯对肥城桃光合作用和果实品质的影响

为了提高肥城桃果实品质,以‘红里’为试材,研究了叶面喷施不同质量浓度的油菜素内酯对肥城桃叶片的叶绿素含量、光合作用及其果实内可溶性固形物含量、可溶性糖含量、蔗糖含量、果糖含量、淀粉含量和单果质量等指标的影响。结果表明,不同的肥城桃发育时期喷施不同质量浓度的油菜素内酯对果实品质的影响不同,硬核期喷施0.10 mg/L的油菜素内酯的处理效果最佳,与对照相比,叶绿素含量、净光合速率、可溶性固形物含量、可溶性糖含量和单果质量分别提高了11.18%、14.42%、8.01%、18.39%和11.88%。     

Regulation of early flowering in Pinus banksiana

Seedlings of three families of jack pine (Pinus banksiana Lamb.) were subjected to 16 combinations of photoperiod, growth environment (outdoors, greenhouse and biotron) and gibberellin (GA(4/7)) treatment. After 14 months, which included two dormancy induction periods, ovulate flowering was observed. There was a strong positive correlation between flowering and seedling height; female flower production was stimulated by both a declining photoperiod during bud development and GA(4/7) treatment; and there was an interaction between GA(4/7) treatment and family, such that the difference in flowering intensity between a late-flowering and an early-flowering family was eliminated by GA(4/7) treatment. The results suggest that the genetic control over the time of onset of flowering, and GA(4/7)-induction of flowering depend on a common mechanism.     

Water stress, photosynthesis and early growth patterns of cuttings of three Populus clones

Photosynthetic attributes, leaf area and early root growth patterns were studied in three Populus clones to identify traits associated with superior growth potential on sites where water could be a limiting factor. It was found that early root growth and superior leaf area production were more closely related to growth potential than were photosynthetic capacity or carboxylation efficiency. A hybrid clone of Populus nigra var. charkowiensis (syn. P. nigra var. plantierensis) x P. nigra cv. 'Incrassata' (NE308) had more leaf area production and greater root system development in both wet and dry soil than did a P. trichocarpa clone (T6) and a P. balsamifera clone (B3). Despite greater above- and below-ground productivity, plants of clone NE308 had significantly lower photosynthetic capacity and carboxylation efficiency and a slightly higher CO(2) compensation point than plants of clones T6 and B3. Rapid early leaf and root growth appear to be key attributes associated with productivity in these clones regardless of soil water availability.     

Vigor-controlling rootstocks affect early shoot growth and leaf area development of kiwifruit

Patterns of shoot development and the production of different types of shoots were compared with scion leaf area index (LAI) to identify how eight clonal Actinidia rootstocks influence scion development. Rootstocks selected from seven Actinidia species (A. chrysantha Merri., A. deliciosa (A. Chev.) C. F. Liang et A.R. Ferguson, A. eriantha Benth., A. hemsleyana Dunn, A. kolomikta (Maxim. et Rupr.) Maxim., A. kolomikta C.F. Liang and A. polygama (Sieb. et Zucc.) Maxim.) were grafted with the scion Actinidia chinensis Planch. var. chinensis 'Hort16A' (yellow kiwifruit). Based on an earlier architectural analysis of A. chinensis, axillary shoot types produced by the scion were classified as short, medium or long. Short and medium shoots produced a restricted number of preformed leaves before the shoot apex ceased growth and aborted, resulting in a 'terminated' shoot. The apex of long shoots continued growth and produced more nodes throughout the growing seasons. Mid-season LAI of the scion was related to the proportion of shoots that ceased growth early in the season. Scions on low-vigor rootstocks had 50% or less leaf area than scions on the most vigorous rootstocks and had a higher proportion of short and medium shoots. On low-vigor rootstocks, a higher proportion of short shoots was retained during pruning to form the parent structure of the following year. Short parent shoots produced a higher proportion of short daughter shoots than long parent shoots, thus reinforcing the effect of the low-vigor rootstocks. However, overall effects of rootstock on shoot development were consistent regardless of parent shoot type and nodal position within the parent shoot. Slower-growing shoots were more likely to terminate and scions on low-vigor rootstocks produced a higher proportion of slow-growing shoots. Shoot termination also occurred earlier on low-vigor rootstocks. The slower growth of terminating shoots was detectable from about 20 days after bud burst. Removal of a proportion of shoots at the end of bud burst increased the growth rate and decreased the frequency of termination of the remaining shoots on all rootstocks, indicating that the fate of a shoot was linked to competitive interactions among shoots during initial growth immediately after bud burst. Rootstock influenced the process of shoot termination independently of its effect on final leaf size. Scions on low-vigor rootstocks had a higher proportion of short shoots and short shoots on all rootstocks had smaller final leaf sizes at equivalent nodes than medium or long shoots. Only later in the development of long shoots was final leaf size directly related to rootstock, with smaller leaves on low-vigor rootstocks. Thus, the most important effect of these Actinidia rootstocks on scion development occurred during the initial period of shoot growth immediately after bud burst.     

Simulated influence of leaf geometry on sunlight interception and photosynthesis in conifer needles

The light interception capabilities of individual conifer needles are governed by their cross-sectional geometry and their orientation to sunlight. Leaf cross sections typical of conifer tree species were modeled to quantify the interception of direct sunlight over a range of incident light angles. The needle shapes exhibited by Abies nordmanniana Spach, Picea asperata Master, Pinus cembra L., P. monophylla Torr & Frém., and P. sylvestris L. were selected because they are representative of the range of geometric shapes found in conifer tree species. Calculated light interception values were compared to corresponding predictions for a laminar broadleaf. Estimates of carbon gain were derived from computed incident light integrated over the leaf cross section and a representative curve of conifer photosynthetic response to light. Flat leaf cross sections (e.g., Abies nordmanniana) with high surface area to volume ratios (> 6) intercepted more light per unit area at high angles of incidence than thick leaves. Thick leaves (e.g., Pinus cembra) intercepted more light at low angles of incidence than at high angles of incidence. Needles of Pinus monophylla had no angular dependence for light interception because of their circular cross section. Large differences in estimated CO(2) assimilation occurred among the species, especially when CO(2) uptake was expressed on a unit volume basis. A maximum uptake of 67.9 mmol CO(2) m(-3) s(-1) was predicted for A. nordmanniana compared to a minimum of 39.7 mmol m(-3) s(-1) for P. monophylla. A greater angular dependence occurred for estimates of CO(2) uptake than for estimates of light interception.     

温度对大叶桃花心木(Swietenia macrophylla King)幼苗叶片的光合影响

本文研究了大叶桃花心木（Swietenia macrophylla King）一年生幼苗在经过夜温处理后的光响应曲线和在饱和光强下的CO2反应曲线.结果表明:在大气CO2浓度下,叶片的最佳光合作用温度在25-31℃之间,而在饱和CO2浓度下为31-35℃.在25℃以下光合速率开始降低,主要是由于羧化效率的降低,而当温度超过31℃时,光合速率下降,是因为羧化效率的降低和呼吸速率的增加.CO2浓度对光合的促进作用在低温下受到抑制,这意味着未来在CO2浓度增高的情况下,高浓度的CO2对热带常绿植物光合的促进在冬天低温情况下表现不十分明显.图4参23.     

刚松子叶数目与早期生长的相关性研究

为揭示刚松子叶数目多少对树木生长量的影响规律,选择优良子叶数目,观测了种粒大小、子叶数目与芽苗、1a生苗和9a生树木生长量的关系,结果均呈极显著或显著正相关关系,即子叶数越多的单株,生长量越大,反之越小,因而选择8枚及7枚子叶数目为刚松优良子叶数目。     

白桦花期诱导技术的研究

在全光照(光合有效辐射尽可能保持在180μmolphotons·m-2·s-1以上)状态下,温度控制在25℃左右,湿度在60%以上,对塑料大棚中的白桦进行绞缢和CO2施肥处理,结果表明:绞缢是促进白桦提早开花的最有效措施,绞缢与对照两个水平间差异显著,绞缢开花率达38%,而对照开花率仅为2.9%。CO2施肥处理与绞缢处理之间不存在相互作用,CO2施肥不能明显使白桦提早开花。     

Inhibitory effect of garlic, clove and carrot on growth ofAspergillus flavus and aflatoxin production

The inhibitory effect of crude extracts of garlic, clove and carrot at concentrations of 20,000, 40,000, 60,000, 80,000 and 100,000 μg/mL on growth ofAspergillus flavus and aflatoxin production in rice was investigated. The results showed that garlic, clove and carrot could inhibit the growth ofA. flavus and aflatoxin production. Garlic and clove at 100,000 μg/mL highly reduced the level of aflatoxin from 5.94 to 0.15 and 0.06 μg/g respectively whereas carrot at 20,000 μg/mL reduced the most level of aflatoxin from 5.94 to 0.03 μg/g. Garlic, clove and carrot at 100,000μg/mL also inhibited the mould growth. The most effective herb for inhibiting the growth ofA. flavus and aflatoxin production was garlic. Responsible Editor: Sun Yueqi     

桂花叶及果实形态性状变异研究

以叶面积、叶长等叶片形态性状和果长、果宽等果实形态性状为指标,研究了桂花叶片和果实形态性状在单株水平上的遗传变异规律。结果表明,桂花叶片和果实等形态性状在单株水平上存在着丰富的遗传变异,且叶片形态性状与果实形态性状由各自独立的遗传基因控制,并受到高等程度的遗传控制,遗传潜力较大。     

木麻黄育苗技术与早期生长效果研究

该研究以海南木麻黄优良种质为主要研究材料,通过水培育苗、营养袋育苗和苗期鉴定遴选出优良品种进行造林,并进行早期生长效果研究,得出一批幼树粗生快长的优良品种,初步实现木麻黄优良品种选育的目的。     

施肥对叶用银杏生长及叶产量的影响

通过对沿海盐碱地生长的5年生叶用银杏实生苗施用N、P、K、NP、NK、PK和NPK等7组肥料试验结果表明,施肥对苗高高峰期的生长有明显的促进作用,其中用N、P等部分处理全年苗高生长量较大;所有施肥处理叶产量的增加值均大于对照,但以N肥效果最好。因此,在沿海盐碱地上应施用N肥或P肥来培育银杏叶用园。     

栽培基质对风信子生长与开花的影响

研究不同基质配比对3个品种风信子生长与开花的影响,结果表明:泥炭与园土等量配比是最佳栽培基质。在此基质中,风信子出苗更早、更整齐、植株更高;叶片更长、更宽、叶面积更大;花的观赏特性也得到提高;风信子叶片叶绿素含量和可溶性糖含量的积累也得到增加;风信子现蕾时间提前;种球的质量也得到较好保持。该基质提高了风信子的综合观赏价值,可作为其通用栽培基质。     

开发乌饭树叶及果实的经济价值

介绍了乌饭树的植物特性、食用价值、药用价值及主要化学成分，提出了开发乌饭树叶和乌饭果的设想。     

气象因子对芳香植物始花期的影响

研究气象因子对芳香植物始花期的影响情况,根据始花期的早迟对指导当地农业生产具有重要意义。对2003—2014年芳香植物的始花期与平均温度、平均最高温度、平均最低温度、降水量、日照时数等气象因子的相关性进行了分析。研究结果表明:芳香植物的始花期与温度关系最密切,降水量和日照时数对始花期的影响不太大。文中还以所测数据建立了芳香植物始花期的预测模型,利用逐步回归分析结果表明:早春和冬季平均最高气温、冬末初春平均最高气温和平均最低气温及平均气温每升高1℃,广玉兰、白玉兰、二乔玉兰、含笑和香樟的始花期分别推迟1.8、5.5、1.4、2.3和2.8 d;冬季平均气温每升高1℃,阴香的始花期推迟4.5 d;开花前5周的平均最低气温每升高1℃,腊梅的始花期推迟2.2 d;晚春平均最低气温、开花前5周的平均气温和平均最高气温及平均最低气温每升高1℃,二乔玉兰、女贞、含笑始花期分别提早5.0、3.3、1.0和2.0 d。