晚大新高梨的净光合速率变化规律初探

利用LI-6400便携式光合测定系统对晚大新高梨进行叶片净光合速率测定研究,结果表明,净光合速率日变化在4、5月份为单峰型,在6、7月份为双峰型,年变化为双峰型。净光合速率Pn在光强为18-1 476 μmol·m-2·s-1时随光强的增强而增大, 净光合速率Pn在CO2浓度为31-963 μmol·mol-1时随CO2浓度的增大而升高,叶片在展叶后23 d内,净光合速率Pn呈上升趋势,23 d后Pn值略有下降,然后趋于稳定。不同部位叶片的净光合速率Pn相比,树冠外围中部最高,下部最低。     

库尔勒香梨砧木组织培养

试验选用库尔勒香梨矮化中间砧S系、F系中的品种嫩茎尖作为试验材料进行了离体增殖研究,结果表明,不同种类的基本培养基及不同浓度配比的植物生长调节剂对试管苗增殖的效果不同。M S培养基较A S、B5培养基更有利于矮化砧S系、F系茎的增殖,中等浓度的细胞分裂素(BA)与较低浓度的生长素(IBA)、赤霉素(GA3)配合使用效果更理想。综合茎质量、茎数量等指标认为:M S BA 1.0 m g/L IBA 0.05 m g/L GA31.0 m g/L是矮化砧S系、F系试管苗茎增殖的最佳培养基。     

臭氧对‘鸭梨’等3种梨果保鲜效果的影响

以‘鸭梨’、‘雪花梨’和‘黄冠梨’为试材,研究了不同浓度的臭氧对梨果品质的影响.结果表明,臭氧处理使‘鸭梨’和‘雪花梨’贮藏期变短,臭氧浓度越大,‘鸭梨’硬度、可溶性固形物、可滴定酸含量下降得越快,果面软化现象发生得越早;臭氧处理延缓了‘雪花梨’可溶性固形物、可滴定酸含量的下降,但使其果点变黑,浓度越大,发生时间越早.臭氧处理延缓了‘黄冠梨’硬度、可溶性固形物及可滴定酸含量的下降,降低了鸡爪病、黑心病的发病率及烂果率,60 mg/m3臭氧处理的‘黄冠梨’贮藏保鲜效果最佳.     

不同含水量苦瓜种子的贮藏研究

苦瓜种子初始含水量为8.81%,用氯化钙为干燥剂将种子含水量降至5.85%、4.09%、3.45%和2.71%。室温下密闭贮藏各批种子,以开放贮藏的种子作为对照,每隔3个月取出检测生活力和活力,包括发芽试验、膜透性试验、挥发性醛含量的测定和抗老化试验。1a的监测结果显示：苦瓜种子开放贮藏时生活力和活力下降最快,经过脱水干燥的种子耐藏性增强,随着种子含水量的降低,生活力和活力增强,2.71%含水量的苦瓜种子贮藏效果最好。     

Extension of fresh-cut “Blanquilla” pear (Pyrus communis L.) shelf-life by 1-MCP treatment after harvest

‘Blanquilla’ pears processed as fresh-cut products are highly sensitive to browning and softening. Common postharvest methods, such as the use of antibrowning compounds and/or modified atmosphere packaging, fail to preserve ‘Blanquilla’ pear slices long enough to be marketable. However, treatment with 1-MCP before cutting and peeling considerably improved their textural properties (9.2 N vs. 1.1 N with and without 1-MCP treatment, respectively) and color (a* values of 1 vs. 5 after 15 d at 4 °C, for slices pear treated with 1-MCP and without treatment, respectively). These positive changes were closely related to a decrease in respiratory activity determined on whole pears after 3 months of storage in air at 0 ± 1 °C and 95% R.H. (0.40 ± 0.05 mmol CO₂ kg⁻¹ h⁻¹ vs. 0.77 ± 0.04 mmol CO₂ kg⁻¹ h⁻¹ with and without 1-MCP treatment, respectively) and ethylene production (1.18 ± 0.36 nmol C₂H₄ kg⁻¹ h⁻¹ vs. 5.751 ± 1.12 nmol C₂H₄ kg⁻¹ h⁻¹ for samples treated with and without 1-MCP, respectively). The use of 1-MCP allows fresh-cut ‘Blanquilla’ pears to be sold up to about 5 d after processing. Treatment with 1-MCP could be a viable alternative to common technologies for extending the shelf-life of ‘Blanquilla’ pears as a fresh-cut product.     

Postharvest pigmentation in red Chinese sand pears (Pyrus pyrifolia Nakai) in response to optimum light and temperature

The development of red color in the peel of red Chinese sand pears (Pyrus pyrifolia Nakai) is influenced by temperature and light; however, the response patterns vary among different cultivars. In this study, we systematically investigated the influence of postharvest treatment with various temperatures (low, high, variant and constant) on detached mature fruit of red Chinese sand pear ‘Mantianhong’ and ‘Meirensu’. Fruit of red apple (Malus domestica Borkh.) ‘Royal Gala’ and red European pear (P. communis L.) ‘Cascade’ received the same treatments for comparison. Furthermore, the effects of light quality and irradiance level on ‘Mantianhong’ pears were evaluated at the optimum temperature for anthocyanin accumulation. Fruit firmness and concentrations of total soluble sugars and organic acids were measured to determine fruit quality. The effect of temperature on red Chinese sand pear fruit color was similar to that of apples, but not European pear. Moreover, low temperature more effectively induced red coloration in ‘Mantianhong’ and ‘Meirensu’ pears than high temperature; anthocyanin levels increased with increasing irradiance level from 0 to 532 μmol m⁻² s⁻¹, and UV-B and visible light synergistically improved the red color of the fruit. Therefore, a combination of low temperature and high intensity of UV-B/visible light could improve the postharvest coloration of red sand pear fruit. The results will contribute to an improved understanding of the mechanism responsible for the coloration of red Chinese sand pears and will aid development of new techniques to improve color in postharvest fruit.     

杨梅自发气调保鲜研究初报

对3种气调保鲜箱贮藏环境的气体成分变化及对杨梅保鲜效果进行了研究。试验结果表明,在0℃冷藏条件下,使用气调保鲜箱杨梅适宜贮藏时间为20天,保鲜效果明显好于对照;气调箱-2效果最好。气调箱-2在贮藏6天时O2、CO2含量达到平衡;在贮藏12～15天时CO2含量达到峰值20.65%,O2含量接近2%,该环境条件有利于杨梅贮藏保鲜。     

成熟期库尔勒香梨理化指标变化规律及相关性研究

为了研究库尔勒香梨成熟过程中理化指标的变化规律,探求成熟期库尔勒香梨主要理化指标间的相关性,以成熟期库尔勒香梨为研究对象,研究库尔勒香梨果实硬度、叶绿素含量、SSC(可溶性固形物含量)和维生素C含量的变化规律;采用相关分析和回归分析的方法,应用Spss软件和Excel软件对指标均值以及各指标间相关性进行了分析,并对试验结果进行了实验验证。研究结果表明:在成熟期内,库尔勒香梨果实理化参数变化范围分别为:硬度4.23~7.99 kg/cm2、叶绿素3.17~6.54 mg/100 g、SSC11.54%~15.41%、维生素C 1.9~4.2 mg/1 0 0 g;随着成熟的深入,果实硬度逐渐降低、叶绿素含量逐渐减少、SSC逐渐增加、维生素C含量逐渐增加;各指标均值在0.01水平上显著相关。回归分析过程中选取最优的拟合方式,并建立相应的数学模型,果实硬度和SSC与叶绿素含量和维生素C含量间决定系数均大于0.95,验证试验预测值与测量值误差小于3.2 1%,在库尔勒香梨成熟过程中可应用果实硬度和SSC对叶绿素和维生素C含量进行预测。研究结果能够为库尔勒香梨成熟度评价和分级提供参考。     

香梨幼林园在不同灌溉条件下生长的动态变化相关分析

在香梨3年生幼林园内,进行了常规沟植、渠道内外二侧种植的土壤贮水量和树木新梢生长量、叶片生长状况变化的测定。结果表明,渠外行的土壤贮水量和生长状况均好于沟植和渠内行。揭示了影响树木生长的不同灌溉条件的土壤水分状况和过程。提出了生产中要提倡渠外行栽种香梨,保持沟植香梨,放弃渠内行栽植香梨的生产模式理论依据。     

基于耕地机犁体自由曲面的数控铣削加工

耕地机犁体曲面是空间任意的曲面。设计合理的犁体曲面,应采用CAD/CAM软件进行实体造型,曲面设计成高速梨曲面,既可以降低无效阻力,又能减轻犁的质量,增强曲面的光滑程度。为此,采用数控加工中心对耕地机犁体空间自由曲面进行铣削加工,选择不同的加工方式和合理的参数,对粗加工时间和精加工结果进行对比分析。结果表明:流线式粗加工和环绕等距式精加工组合有更高的加工效率和更好的质量,能使耕地机减少抛扔的能量消耗,提高耕地机零部件的加工效率。