硫脲改性榴莲壳对水溶液中Pb2+、Cd2+的吸附研究

采用硫脲改性榴莲壳,制备新型的改性榴莲壳吸附剂,研究其对Pb2+、Cd2+的吸附性能。结果表明,吸附Pb2+、Cd2+的适宜条件为:pH 6.0,吸附时间60 min。改性后榴莲壳吸附剂对Pb2+、Cd2+的吸附容量能有了很大程度的提高,Pb2+、Cd2+最大吸附量分别达到53.63、34.84 mg.g-1。吸附过程可以很好地用准二级动力学方程描述,吸附等温线用Langmuir方程的拟合效果优于Freundlich方程。     

榴莲壳多糖微波提取及脱蛋白方法

[目的]优化榴莲壳多糖的微波提取及脱蛋白最佳工艺。[方法]采用L9(34)正交试验,以多糖含量为评价指标,利用苯酚-硫酸法测定多糖的含量,确定多糖的提取工艺;以脱蛋白率与多糖损失率为指标,选择最佳脱蛋白方法。[结果]最佳提取工艺为料液比1∶30g/ml,微波功率450 W,提取时间6 min,提取次数为1次;三氯乙酸法(TCA)为最佳脱蛋白方法。[结论]优化后的工艺条件稳定可行,可为榴莲壳多糖工业化生产提供理论依据。     

The growth pattern and nutrient uptake of durian (Durio zibethinus Murr.) on an oxisol

Abstract

The growth pattern and element uptake during early years of production of durian (Durio zibethinus Murr.) was studied using various ages of trees growing at Serdang, Malaysia. Growth was rapid until the seventh year when the dry matter production was nearly at its maximum. The proportion of underground to above ground materials decreases as the tree ages and in a seven‐year old tree, 30% is roots and 70% tops. The elements (N, P, K, Ca and Mg) stored in the vegetative parts increases with the age of the tree in a similar manner to that of the total dry matter. However, the amount of elements stored in a seven‐year old tree exceeds that which, was applied as fertilizers suggesting that the once‐jungle tree obtains additional elements from the soil. The element removed in fruits during the first two years of production was low. In general, the growth and early production of durian on an Oxisol, using the agronomic practices adopted at Serdang, are satisfactory.     

泰国榴莲上棕榈疫霉的分离和鉴定

在对来自泰国的榴莲检验中分离到1株引起榴莲果皮和果肉变色、软腐的病原真菌。通过形态鉴定和核糖体ITS区DNA序列测定以及系统发育分析,最终将该病菌鉴定为棕榈疫霉(Phytophthora palmivora)。     

榴莲PEPC基因家族全基因组鉴定及表达分析

本研究从榴莲全基因组中鉴定榴莲PEPC基因,并分析了它们在‘猫山王’榴莲不同组织(根,茎,叶和果肉)与3个不同品种(‘猫山王’,‘金枕头’和‘普玛尼’)果肉中的表达情况。结果共获得6个榴莲Dz PEPC家族成员,其蛋白理化特征较为相似,且所有榴莲PEPC蛋白亚细胞定位预测均可能存在于细胞质中。染色体定位显示榴莲PEPC位于5条不同的染色体。联合榴莲、水稻、菠萝、拟南芥的PEPC蛋白共同进行系统进化分析,结果显示共可分为2个亚组,Dz PEPC1、Dz PEPC3、Dz PEPC4和Dz PEPC5为PTPC亚族(植物型),Dz PEPC2和Dz PEPC6为BTPC亚族(细菌型),且发现榴莲PTBC和BTPC分离时间早于单子叶植物和双子叶植物的分离时间,两者基因结构和蛋白序列差异大,但仍具有一定的保守性。顺式作用元件分析显示,DzPEPC含有数量较多的光响应元件和激素响应元件。转录组表达分析发现,DzPEPCs在不同榴莲组织中的表达具有偏好性,可能参与榴莲的多个生物学过程(包含光合和非光合过程),并初步推测DzPEPC4与榴莲果肉发育过程相关。本研究可为进一步探究DzPEPC家族在榴莲中的生物学功能提供参考。     

Effect of 1-methylcyclopropene (1-MCP) on storage life of durian fruit

Fruit of cv. Monthong durian (Durio zibethinus) were treated with 0 (control) or 500 nL L⁻¹ 1-MCP for 12 h at 25 °C. Fruit were then stored at 15 °C. To determine storage life, every 3 days a batch of fruit was transferred to 25 °C. The time to ripeness (adequate eating quality) at 25 °C in controls (no 1-MCP) decreased from 5 days in freshly harvested fruit to 3 days after 18 days of storage at 15 °C. Storage life was considered adequate if the time to ripeness was ≥3 days. The storage life at 15 °C of control fruit (no 1-MCP) was therefore 18 days. After the 1-MCP treatment the time to ripeness at 25 °C was 7 days in fresh fruit, while in fruit stored at 15 °C for 30 days it was about 3 days. The storage life at 15 °C of 1-MCP-treated fruit was therefore 30 days. Pulp firmness and pulp total soluble solids (TSS) were determined after 3 day storage intervals at 15 °C and when the fruit was ripe at 25 °C. These parameters were only slightly affected by the 1-MCP treatment. Furthermore, 1-MCP had no effect on pulp color, but delayed yellowing of the fruit exterior. It is concluded that treatment with 1-MCP before storage at 15 °C extended storage life from 18 to 30 days.     

Effective pollination period in durian (Durio zibethinus Murr.) and the factors regulating it

The effective pollination period (EPP) of durian was determined by both delayed and bud pollination, during which reproductive factors affecting the EPP, e.g., stigma receptivity, pollen tube growth in the style, and ovule longevity were studied histologically. This study was conducted in three distinct locations in Thailand, namely, the Chantaburi Horticultural Research Center and two private orchards in Chantaburi and Trat provinces. Results from artificial pollination revealed that at anthesis, the durian flower is receptive and has a high fruit set ratio. A mean fruit set of 50% was obtained at anthesis in the private orchard in Chantaburi province. However, the EPP of durian was found to be very short, lasting for only one night; the fruit set from pollination on the morning after anthesis ranged from 0% to 3.4%. No fruit set occurred following pollination 24 or more hours after anthesis. When compared with the flowers of other fruit species, the durian flower has a unique feature in that it blooms overnight; the following morning, there is abscission of all parts of the flower, except the gynoecium. Thus, EPP appears to be synchronized with flower longevity. On the other hand, the durian flower was receptive several hours before anthesis. The results of chemical tests, including the hydrogen peroxide test and Perex-Test^®, for the evaluation of stigma receptivity appeared to be in agreement with the EPP. However, fluorescent microscopy revealed that pollen could germinate even in the stigmas pollinated 48 h after anthesis, but the number of pollen tubes at the top of the style rapidly decreased from 34.6 (at anthesis) to 0.5 (48 h after anthesis). A correlation test demonstrated a higher correlation coefficient between the fruit set and the number of pollen than that between the fruit set and the result of Perex-Test^®. This indicated that pollen tube penetration or elongation in the style was inhibited, probably due to the deterioration of nutritional support from the pistil to the pollen tubes; this can be a limiting factor of the EPP in durian.     

离子色谱-积分脉冲安培检测法测定榴莲中的17种氨基酸

[目的]了解榴莲各部分的食用和药用价值,以便为其开发和综合利用提供依据。[方法]采用AminoPaePA—10氨基酸分析柱,用积分脉冲安培离子色谱法测定榴莲中17种氨基酸及其含量。[结果]各组分的线性关系良好,相关系数在0．9907～0．9998,加标回收率在80．0％～112．9％,检出限在0．0028～0．0136μmol／L之间。pH=12～13时,氨基酸的洗脱顺序大体是：碱性氨基酸、中性氨基酸、酸性氨基酸。流动相中Ac^-与阴离子交换树脂的亲和力要大于OH^-。各氨基酸在0．05～25．0nmol／L范围内线性关系良好。精密度检测的RSD在1．2％-2．7％。重复性检测的RSD在2．3％-8．4％。加标回收试验的平均回收率在80．O％～112．9％。[结论]该法具有灵敏度高、精密度好、分离速度快和样品不需要衍生处理的优点。     

Firmness and activities of polygalacturonase, pectinesterase, β-galactosidase and cellulase in ripening durian harvested at different stages of maturity

The changes in ripening durian aril firmness, water-soluble pectin and polygalacturonase, pectinesterase, β-galactosidase and cellulase activities were determined in fruit harvested at two stages of maturity. Polygalacturonase activity was low in unripe durian aril and increased markedly during ripening. The development of polygalacturonase activity paralleled the formation of water-soluble pectin and decline in firmness. Pectinesterase, β-galactosidase and cellulase activities were high in unripe durian aril and only pectinesterase and β-galactosidase activities increased slightly while cellulase activity was present throughout during ripening. Water-soluble pectin and polygalacturonase and pectinesterase activities were greater in more mature durian aril than in less mature durian aril, whereas firmness and the activities of β-galactosidase and cellulase were less in the more mature durian aril. The roles of polygalacturonase and pectinesterase in softening of ripening durian aril are discussed.