哈密瓜削皮机之仿形机构的研究

本文介绍了一种适用于哈密瓜机械削皮机的仿形机构,并就其结构形式和主要结构尺寸进行了初步的设计。该仿形机构的特点是结构简单、仿形灵活,且仿形力可进行准确的变换。     

Fruiting position during development of ‘Nules Clementine’ mandarin affects the concentration of K,Mg and Ca in the flavedo

Adequate K, Mg and Ca supply is important to develop well-structured and functional cell walls and membranes in fruit, and insufficient levels or imbalances of these minerals are known to be involved in various postharvest disorders. Microclimatic variation exists in the ‘Nules Clementine’ mandarin tree canopy and results in lower photosynthetically active radiation (PAR) levels and temperature as well as a higher humidity inside the tree canopy. The aim of this experiment was to determine the impact of this variation in microclimate on accumulation patterns of K, Ca and Mg in the flavedo of the fruit rind during stages II and III of fruit development. Fruit mass, dimensions, rind colour development and mineral composition of the flavedo were measured to describe the condition of fruit borne on the outside and inside of the tree's canopy. The data revealed that canopy position influenced mineral nutrient accumulation patterns in the flavedo. Outside fruit flavedo accumulated significantly higher concentrations of Ca and Mg in all three seasons (2005–2007). In contrast, inside fruit flavedo (shaded fruit) accumulated significantly higher levels of K compared with outside fruit flavedo. The accumulation of K and Ca differed from that of kiwifruit and apple in that Ca concentration increased and K decreased towards maturity. These results suggest that xylem, as in citrus leaves, is the main vasculature supply conduit to the citrus fruit flavedo for mineral nutrients. The reduction of transpiration potential by lower temperatures and higher humidity inside the canopy could be responsible for the reduced accumulation of Ca and Mg. The high K concentration of inside fruit flavedo is suggested to be a stress response, due to the low light levels, to maintain osmotic potential in the shaded rind tissue, and this imbalance could possibly lead to a reduction in rind condition, which manifests through rind breakdown symptom development.     

种植密度对3个紧凑型玉米品种抗倒伏性和产量的影响

以郑单958、先玉335、浚单20为材料,研究不同密度下3个紧凑型玉米品种抗倒伏性和产量的影响。结果表明,随着密度增加,3个玉米品种的倒伏率逐渐升高,平均倒伏率浚单20先玉335郑单958。随着密度增加,玉米株高、穗位高、穗高系数均逐渐升高,玉米倒伏率与穗位高呈极显著正相关,与株高和穗高系数相关性不显著。玉米茎秆穿刺强度随着节位的上升呈下降趋势,随着密度增加,茎秆穿刺强度逐渐降低,不同密度下每一节的穿刺强度均为先玉335郑单958浚单20,不同节间的穿刺强度表现为第二节第三节第四节第五节第六节。随着密度增加,玉米穗行数、穗粒数和百粒重均呈降低趋势,行粒数在不同品种间表现不同,郑单958和先玉335均呈下降趋势,浚单20则先升后降。随着密度增加,郑单958、先玉335的产量表现为先升高后降低的趋势,在7.5万株/hm2时达最高值,分别为13 141.5、14 324.2 kg/hm~2,浚单20呈下降趋势。因此,与郑单958和浚单20相比,先玉335在冀西北地区种植抗倒伏且获得高产。     

网纹甜瓜网纹形成发育研究进展

优美的网纹是网纹甜瓜一个重要品质特征。本文综述了网纹甜瓜网纹形成发育过程中的果实表皮细胞特征,网纹发育相关过氧化物酶活性和相关植物激素对网纹形成的影响,并概括了影响网纹发育的相关外源因素,指出了今后的研究方向。     

种植密度对玉米茎秆和穗部性状的影响

以郑单958、金海5号为试验材料,研究在中密度(52 500株/hm²)、高密度(75 000株/hm²)条件下对茎秆和穗部性状的影响。结果表明：高密度条件下,两个品种株高和穗位高受影响均不显著,除第1节间茎秆长度显著增加外,其他节间受密度影响不显著,而基部(第3节间)茎的粗度显著减少;中密度条件下,金海5号各节间茎秆穿刺强度均显著大于郑单958。高密度条件下,金海5号各节间茎秆穿刺强度显著减弱,而郑单958除第3节间穿刺强度显著减弱外,其他节间没有明显变化。高密度条件下,穗长、行粒数和百粒重都显著降低。两个品种在高密度下的产量均显著高于中密度。     

Veränderungen im Thrombozytengehalt milzektomierter Mäuse nach Injektion von Embryo derived-Platelet activating Faktor

Inhalt Maus- und Kaninchenembryokulturmedium verursachte bei milzektomierten Mäusen eine signifikante Verminderung des Thrombozytengehaltes. Das selbe Ergebnis wurde nach Injektion (i.p.) von einer geringen Dosis PAF-acether erreicht. Ein und mehrere Rinderembryonen produzierten in vitro Embryo-derived platelet activating Factor (EDPAF), der in milzektomierten Mäusen eine Thrombozytopenie bewirkte. Dieser Effekt trat nach Injektion von Kulturmedium, in dem unbefruchtete Eizellen inkubiert wurden, nicht auf.
Der Nachweis des EDPAF im Rinderembryokulturmedium mittels eines Bioassay kann angewendet werden:
(1) als eine quantitative und nicht invasive Methode für die Bestimmung der Vitalität von in vitro kultivierten Embryonen
(2) für eine qualitative Kontrolle des Embryokulturverfahrens.
Contents: Alterations of platelet count in splenectomized mice after injection (i.p.) of embryo derived platelet activating factor
The application of mouse and rabbit embryo culture media caused a significant reduction in the platelet count of splenectomized mice. The same result was observed after i.p. injection of small dose of PAF-acether. One or several bovine embryos were able to produce an embryo derived platelet activating factor (EDPAF) in vitro which caused thrombocytopenie in splenectomized mice. This effect did not occur after injection of culture medium in which unfertilized ova were incubated. The detection of EDPAF in bovine embryo culture medium by a bioassay can be used:
(1) as a quantative and noninvasive method to assess the viability of embryos after in vitro culture
(2) as a method for quality control of embryo culture procedures.     

Morphokinese der Nebennierenrinde beim Rind nach ein-oder mehrfacher Glukokortikoidapplikation zur Geburtseinleitung

Morphometrisch untersucht wurden die Nebennieren von 27 Kühen mit und ohne medikamentelle Geburtseinleitung bzw. nicht tragender Kontrolltiere (Gruppe I (n = 7): 10 mg Triamcirwlon −6,5 d ante partum und 10 mg Flumethason −30 h ante partum; Gruppe II (n = 6): 1 ml NaCl (Placebo) −6,5 d ante partum und 10 mg Flumethason −30h ante partum; Gruppe III (n = 4): tragend, keine Vorbehandlung; Gruppe IV (n = 10): nicht tragende Kontrolltiere). Eine Geburtsinduktion mit Glukokortikoiden führt zu einer signifikanten Verkleinerung der Kerngröβen sowie einer Zunahme der Zellkernzahl pro definierter Flächeneinheit in der Zona fasciculata und einer signifikanten Verschmälerung von Zona fasciculate/Zona reticularis. Diese Befunde werden als medikamentell induzierte regressive adrenokortikale Transformation interpretiert.
Contents: Morphokinesis of the adrenal cortex in cattle after induced parturition by single or repeated glucocorticoid application
Adrenal glands of 27 cows with or without induced parturition and non-pregnant controls were investigated morphometrically (Group I (n = 7): 10 mg Triamcinolone - 6,5 d ante partum and 10 mg Flumethasone −30 h ante partum; group II (n = 6): 1 ml NaCl (placebo) - 6,5 d ante partum and 10 mg Flumethasone −30 h ante partum; group III (n = 4): pregnant, nopretreatment; group N(n= 10): non-pregnant controls). Pretreatment with glucocorticoids results in a significant reduction of nuclear sizes and an increase in number of nuclei per area unit defined in the zona fasciculata, combined with a significant decrease of the width of zona fasciculate/zona reticularis. These findings are interpreted as indicator for a medicamentally induced regressive adrenocortical transformation.     

遮荫对玉米茎秆形态特征、穿刺强度及抗倒伏能力的影响

大田条件下,研究遮荫处理对玉米不同类型品种的茎秆形态特征及抗倒力学强度的影响。结果表明:稀植大穗品种JK519对弱光胁迫反应较为敏感,遮荫处理后玉米株高和穗位高均显著下降,叶面积指数降低。基部节间缩短、直径变小,单位节间长干质量减少。茎秆穿刺强度在30%和60%遮荫条件下分别下降36.4%和66.0%,田间倒伏率严重。而紧凑耐密品种CS1在遮荫30%胁迫下穗位高、LAI下降不明显;节间缩短,但直径和单位节间长干质量变化不大;穿刺强度仅下降5.9%,田间倒伏较轻;在遮荫60%胁迫下,穿刺强度明显下降,倒伏加重。同时各个品种均随遮荫程度的增加,最终玉米产量、收获穗数、单穗粒数和千粒重明显降低。因此,30%遮荫处理(弱光胁迫)可推荐作为玉米高产抗倒品种茎秆力学强度鉴定和筛选条件之一。     

Canopy position affects rind biochemical profile of ‘Nules Clementine’ mandarin fruit during postharvest storage

This study was conducted to investigate the effects of preharvest canopy position and bagging treatments on rind physiological and biochemical properties of ‘Nules Clementine’ mandarin (Citrus reticulata Blanco) fruit. Before storage, the respiration rate of unbagged outside fruit was significantly higher (21.6 mL CO₂ kg⁻¹ h⁻¹) than of bagged inside fruit (16.3 mL CO₂ kg⁻¹ h⁻¹). Unbagged fruit outside the canopy had 1.4-fold higher carbohydrates, and 1.1-fold higher dry matter (DM) content than bagged inside fruit. Bagged fruit inside the canopy had higher (24%) weight loss than outside sun-exposed fruit (14%). This corresponded with a higher rind breakdown (RBD) index for bagged inside fruit, compared to sun-exposed fruit which did not develop the disorder. During postharvest storage, rind fructose levels of bagged fruit inside the canopy increased from 62.4 mg/g DM at harvest to 81.3 mg/g DM after 8 weeks, while those of unbagged outside fruit increased from 97.9 to 108.4 mg/g DM. Concomitant with the increase in fructose, sucrose in rind tissue of bagged inside fruit decreased from 42.6 to 27.7 mg/g DM and from 49.3 to 33.4 mg/g DM for unbagged outside fruit. Rind glucose of unbagged inside fruit decreased from 90.6 to 76.2 mg/g DM. Ascorbic acid concentrations remained almost constant during storage, with levels between 3.3 and 6.7 mg/g DM for inside bagged and unbagged outside fruit, respectively. Hesperidin was the major flavanone detected, with concentrations between 35 and 45 mg/g DM followed by narirutin (1.1–2.8 mg/g DM). At harvest, rind of fruit harvested from outside the canopy had lower hesperidin concentration (38.1 mg/g DM) compared to shaded fruit (44.2 mg/g DM). Overall, the results suggest that variations in microclimatic conditions inside the tree canopy during the growing season affect the biochemical profile of the fruit rind, which in turn influences fruit response to postharvest stresses associated with senescence and susceptibility to RBD.