根区滴灌对干旱山地苹果树生长发育和结实的影响

根区滴灌是将雨水促渗管与传统滴灌相结合而组装集成的一项节水灌溉新技术。为了探讨根区滴灌在山地果园的应用效果,为山地果园的栽培管理提供依据,本文以陕北米脂县6 a生山地红富士苹果树为研究对象,以世界公认的最佳苹果优生区洛川县的降雨量和土壤贮水量为灌水依据,分析了不同灌溉方式对苹果树萌芽、坐果、枝叶生长、果实发育和水分利用效率的影响,以及山地果园土壤水分达到优生区标准后与优生区苹果树生长结果的差异。结果表明,采用根区滴灌能有效提高苹果树的萌芽率和坐果率,萌芽率比传统滴灌提高了2.14%~2.76%,坐果率比传统滴灌提高了0.80%~1.42%;能有效促进苹果树新稍和叶片的生长,新稍长度比传统滴灌提高了1.44%~4.94%,百叶鲜质量比传统滴灌提高了2.13%~4.16%;能显著促进苹果树果实的生长,单果重比传统滴灌增大了7.05~14.99 g,优果率比传统滴灌提高了9.4%~14.7%;能显著提高水分利用效率,灌水量比传统滴灌节约了8.09%,水分利用效率比传统滴灌提高了10.62%~15.30%。可见,根区滴灌技术在陕北黄土丘陵区山地苹果生产中具有广阔的应用效果,但是,单纯依靠人为限量补水,山地苹果还不能达到优生区的生产水平。     

甲壳素对连作平邑甜茶生长、光合及抗氧化酶的影响

以苹果连作土盆栽的平邑甜茶幼苗为试材,探讨了0、0.5、1.0和2.5 g·kg-1不同施入量的甲壳素对其光合速率、活性氧含量及抗氧化酶活性的影响。结果表明,1.0 g·kg-1的甲壳素处理能显著促进幼苗株高、地径,干样质量和根冠比的增加,根冠比为对照的1.51倍;明显提高了幼苗叶片光合色素含量、净光合速率和蒸腾速率,其中光合速率为对照的1.30倍;同时提高了幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性,分别为对照的1.10倍、1.85倍、1.77倍和1.43倍;减少了叶片丙二醛(MDA)、过氧化氢(H2O2)和超氧阴离子的积累,分别为对照的73%、62%和34%,降低了脯氨酸(Pro)和可溶性糖含量。当甲壳素施用量为2.5 g·kg-1时则显著抑制平邑甜茶幼苗生长,降低幼苗叶片光合速率和抗氧化酶活性,并使超氧阴离子和脯氨酸含量明显上升。因此,适宜用量的甲壳素能减轻苹果的连作障碍。     

不同药剂对苹果树腐烂病伤口愈合效果研究

为探讨苹果腐烂病的有效防治方法,研究比较了春季休眠期和萌芽期用纯泥、多菌灵药泥、拂蓝克、人工树皮二代和愈合剂5种药剂处理对苹果树伤口愈合面积和形成愈伤组织鲜干重的影响。结果表明:休眠期形成的伤口愈合情况好于萌芽期形成的伤口;使用多菌灵药泥包裹处理伤口愈合面积、愈合比例最大,分别为7.05cm2和99.76%。愈伤组织鲜干重也最大,伤口愈合效果最好。建议春季在休眠期使用多菌灵药泥对苹果腐烂病进行伤口处理。     

MdMYB73的分子克隆及其在苹果愈伤组织和拟南芥幼苗中的盐抗性功能鉴定

从‘嘎拉’苹果中克隆了一个MYB转录因子基因(序列号:MDP0000894463)。该基因包含长为729 bp完整的开放阅读框,编码243个氨基酸,预测其蛋白质分子量为26.34 kD,等电点为9.29。系统进化树分析表明,这一MYB转录因子与拟南芥AtMYB73同源序列相似性最高,因此将其命名为MdMYB73。功能域分析表明,MdMYB73蛋白含有保守的R2R3-typeMYB绑定域。荧光定量PCR分析表明,MdMYB73在苹果的各个组织均有表达,在叶片和花中表达相对较高;MdMYB73的表达明显受盐胁迫的诱导。将异位表达MdMYB73的拟南芥幼苗进行抗盐鉴定,结果表明MdMYB73负调控拟南芥盐胁迫抗性;同时,AtSOS1,AtSOS3和AtNHX1抗盐相关基因的表达水平显著降低,表明MdMYB73可能负调控SOS反应,影响拟南芥抵抗高盐胁迫过程。将MdMYB73基因遗传转化苹果愈伤组织,抗盐表型分析表明,MdMYB73过量表达也明显降低了转基因愈伤组织对盐胁迫的抗性。     

白三叶返园对苹果园土壤微生物群落的影响

为了解苹果(Malus pumila)园中覆盖和埋置白三叶(Trifolium repens)对土壤微生物群落的影响,采用尼龙袋法将新鲜的白三叶覆盖和埋置到苹果园中,分别在白三叶降解1、3、6个月时,利用Biolog微平板法检测土壤微生物群落的功能多样性。结果表明,覆盖和埋置白三叶均可使苹果园土壤微生物代谢活性显著提高(P0.05),微生物的多样性除6个月外显著增加、丰富度显著增加,均匀度显著降低(P0.05),群落结构发生变化,且覆草处理大于埋草,同时,白三叶降解时间的长短也影响土壤微生物群落。土壤微生物群落主成分分析结果显示,不同返园方式间主要对羧酸类碳源的利用有差异,而导致不同降解时间土壤微生物群落代谢差异的主要是糖类。说明在苹果园覆盖和埋置白三叶可改变土壤微生物群落,而覆盖白三叶对微生物群落结构的改善情况显著优于埋置白三叶。     

基于高斯自适应拟合的苹果目标分割方法研究

苹果目标的准确识别是苹果机械化采摘需要解决的关键问题之一。为此,基于YUV颜色空间模型,提出了一种结合色差分量与高斯自适应拟合算法的苹果目标分割方法。该方法采用首先将苹果目标由RGB颜色空间转换至YUV颜色空间,并利用色差分量V建立果实与背景分割的高斯分布拟合模型,根据拟合结果自动获取分割阈值,以实现自然场景下苹果目标的准确分割。为了验证文中算法的有效性,利用多幅图像进行了试验并与Otsu自适应阈值分割算法进行了比较。试验结果表明,采用文中算法得到的苹果果实的平均检出率达87.08%,识别率领先Otsu算法9.91%。因此,对于着色度较为均匀的苹果目标,采用高斯自适应拟合方法可以有效提高其识别率。     

Effects of apple pomace proportion levels on the fermentation quality of total mixed ration silage and its digestibility,preference and ruminal fermentation in beef cows

Four Japanese black beef cows were used in a 4 × 4 Latin square to evaluate the fermentation quality, digestibility, ruminal fermentation and preference of total mixed ration (TMR) silages prepared with differing proportions of apple pomace (AP). Experimental treatments were the control (no AP added, CAP), 5% (low, LAP), 10% (medium, MAP) and 20% (high, HAP) of TMR dry matter (DM) as AP. All TMR silages were well preserved. Ethanol was produced in silages containing AP and the amount increased with the proportion of AP (P < 0.05). Nutrient digestibility with LAP, MAP and HAP treatment was lower than that with CAP treatment (P < 0.05). The ruminal molar proportion of acetic acid increased (P < 0.05), but the ruminal ammonia‐N concentration decreased (P < 0.05) as the proportion of AP increased. The preference of the animals was highest for HAP, followed by MAP, CAP and LAP. This study demonstrates that decrease in nutrient digestibility might be related to the ethanol produced naturally from AP. Therefore, the proportion of AP in TMR silages should be less than 5% of dietary DM.     

Effects of apple pomace‐mixed silage on growth performance and meat quality in finishing pigs

We measured the growth performance and meat quality of 10 crossbred (Yorkshire × Duroc × Landrace) neutered male pigs to evaluate the effects of apple pomace‐mixed silage (APMS). The pigs were divided into two groups and were respectively fed the control feed and the AMPS ad libitum during the experiment. No difference was found in the finished body weight, average daily gain, carcass weight, back fat thickness or dressing ratio between the control and the AMPS treatments, but average dairy feed intake (dry matter) was significantly lower and feed efficiency was significantly higher using the APMS treatment (P < 0.05). With regard to meat quality, the APMS increased the moisture content but decreased the water holding capacity (P < 0.05) compared with the control treatment. Furthermore, the APMS affected the fatty acid composition of the back fat by increasing linoleic acid (C18:2n6), linolenic acid (C18:3) and arachidic acid (C20:0) levels, while decreasing palmitic acid (C16:0), palmitoleic acid (C16:1) and heptadecenoic acid (C17:1) levels, compared with the control treatment. These results indicate that feeding fermented apple pomace to finishing pigs increases the feed efficiency and affects the meat quality and fatty acid composition of back fat.     

The influence of polyphenol rich apple pomace or red-wine pomace diet on the gut morphology in weaning piglets

Alternative food ingredients, e.g. secondary plant compounds, are discussed to have beneficial effects and improve gut health. In this study, the effect of three different diets - normal piglets starter without additives, with apple pomace or with red-wine pomace - on the intestinal morphology was investigated from 3 days prior to weaning to 4 weeks post-weaning. At five time points, six piglets from each treatment group were slaughtered; at first time point only six animals from control group were slaughtered. Villus height, crypt depth and breadth of villi and crypts were determined in the jejunum, ileum and colon in 78 piglets. Additionally, the area of the Peyer's patches in the ileum was measured. In jejunum (p < 0.01) and ileum (p < 0.001) the villus length in the control group decreased after weaning but increased over the entire feeding experiment (p < 0.001). In the two-pomace groups, no decrease was measured after weaning. In jejunum, an increase in villi breadth occurred, 73% in the control group and approximately 10% in both treatment groups. A 35% increase was found in the ileum in all groups. Peyer's patches area increased approximately 21% in the control group over 26 days of treatment, whereas in other groups no significant differences were found. Different polyphenol rich pomaces have diverse effects in the gastrointestinal tract. Red-wine pomace has an inhibitory effect on the jejunum villi growth, whereas apple and red-wine pomace have stimulating effect on crypt size in piglet colon. Apple and red-wine pomace can reduce the GALT activation via the Peyer's patches in the ileum. In conclusion, the flavanoids rich feeding regimen showed positive effects on villi morphology, GALT activation and can improve pig health.     

苹果轮纹病菌对吡唑醚菌酯的敏感性及Cytb基因序列分析

为了明确苹果轮纹病菌Botryosphaeria dothidea对吡唑醚菌酯的敏感性和吡唑醚菌酯的靶标基因序列, 采用菌丝生长速率法测定了水杨肟酸对B. dothidea 菌丝生长的作用, 探讨了添加或不添加水杨肟酸的情况下病原菌对吡唑醚菌酯敏感性的变化; 并测定了不同产区的80株B. dothidea 对吡唑醚菌酯的敏感性以及440株B. dothidea 对吡唑醚菌酯的抗性; 然后, 扩增并分析了具有不同敏感性的菌株的细胞色素b基因 (Cytb) 序列?结果表明:不同浓度水杨肟酸对菌丝生长的抑制作用不同?添加40 μg/mL水杨肟酸不影响吡唑醚菌酯的EC50?菌株的敏感性频率符合近似正态分布, 各产区菌株对吡唑醚菌酯的敏感性没有显著差异, 吡唑醚菌酯平均EC50为(2.95±2.11) μg/mL, 没有检测到抗性菌株?靶标基因序列分析表明, Cytb基因在F129?G137和G143位密码子上没有产生点突变, 首次发现在143位密码子后有内含子插入?