‘徐香’与‘海沃德’猕猴桃冷藏期间组织结构与生理变化差异

以猕猴桃‘徐香’（较不耐贮藏）和‘海沃德’（耐贮藏）果实为试材,研究其在0 ℃贮藏期间生理及组织结构的变化差异,从而探究其与耐贮性的关系。结果表明：贮藏期间两品种果肉硬度均不断下将,‘海沃德’果肉硬度降至10 N的时间为150 d,而‘徐香’仅为95 d;‘徐香’的呼吸高峰和乙烯释放高峰的出现分别较‘海沃德’早20 d和10 d,且峰值分别高出16%和250%。贮藏期间‘徐香’果实的质量减少率也显著高于‘海沃德’。在整个贮藏期间,‘海沃德’果实的淀粉、原果胶、纤维素含量均高于‘徐香’,而淀粉酶（AM）、果胶代谢相关酶（多聚半乳糖醛酸酶PG、果胶甲酯酶PE、β–半乳糖苷酶β-Gal）和纤维素酶（Cx）的活性高峰值均低于‘徐香’。‘海沃德’的表皮毛极显著细短于‘徐香’;且角质层厚度及表皮细胞层数都大于‘徐香’;贮藏期间果肉细胞的形变程度‘海沃德’小于‘徐香’;‘海沃德’的细胞壁厚于‘徐香’,且贮藏期间中胶层分裂缓慢,线粒体较完整。总之,耐贮性好的猕猴桃品种角质层和表皮细胞厚,质量减少率较低,呼吸速率和乙烯释放速率慢,细胞壁酶活性低。     

Evaluation of the wild Actinidia germplasm for resistance to Pseudomonas syringae pv. actinidiae

Bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) is a catastrophic disease that threatens the global kiwifruit industry. As yet, no cure has been developed. Planting resistant cultivars is considered as one of the most effective ways to control Psa. However, most existing cultivars lack Psa-resistance genes. Wild Actinidia resources contain rich genetic diversity and may have powerful disease-resistance genes under long-term natural selection, but lack of knowledge about the resistance to Psa for most Actinidia species results in some excellent wild resistant genotypes being underutilized. In this study, the response to Psa of 104 wild genotypes of 30 Actinidia species (including 37 taxa) was tested with an in vitro bioassay, and a considerable number of individuals from different species with tolerance or high resistance to Psa were identified. The results showed high consistency between years. This is the first large-scale evaluation of diverse Actinidia species with resistance to Psa through an in vitro bioassay. The resistant genotypes of A. chinensis identified could be used in future kiwifruit improvement programmes. The findings should help provide an understanding of the resistance to Psa.     

猕猴桃褪绿环斑相关病毒在陕西省的分布、分子变异及其2个分离物的基因组序列

为明确我国陕西省猕猴桃主产区的徐香、海沃德、华优和秦美4个猕猴桃品种上的猕猴桃褪绿环斑相关病毒(Actinidia chlorotic ringspot-associated virus,AcCRaV)的分布情况,对采集自该省4个地区的493份样品进行AcCRaV检测,基于cp基因序列对获得的AcCRaV分离物进行分子变异分析,并采用高通量测序技术对其中2份样品进行转录组测序。结果显示:AcCRaV在陕西省猕猴桃上分布广泛,且检出率较高,其中周至县秦美猕猴桃上AcCRaV的检出率最高,为45.0%,在杨凌区秦美猕猴桃上AcCRaV的检出率最低,为10.0%。测定的23个AcCRaV分离物cp基因序列全长均为945 nt。系统发育树显示AcCRaV分离物共分成2个组,存在较大的分子变异。AcCRaV的cp基因分子变异与猕猴桃品种有一定关系,而与地理位置相关性不明显。获得了2个AcCRaV分离物ZZ1和ZZ2的基因组序列,RNA1长度分别为7 049 nt和7 274 nt,RNA2长度均为2 266 nt,RNA3长度分别为1 691 nt和1 696 nt,RNA4长度分别为1 736 nt和1 683 nt,RNA5长度分别为1 460 nt和1 497 nt。分离物ZZ1和ZZ2的基因组序列与GenBank中唯一报道的我国湖北省AcCRaV分离物HN-6基因组序列比对中,分离物ZZ2与HN-6的RNA4同源率最高,为96.0%,分离物ZZ2与HN-6的RNA1同源率最低,为87.8%。表明AcCRaV在我国陕西省猕猴桃主产区分布较广泛,且其分子变异与猕猴桃品种有一定关系。     

红阳猕猴桃引种试验示范

为了优化贵州猕猴桃品种结构,提高猕猴桃果品质量,使猕猴桃产业能更好地发展。2000年在贵州省水城县引种试验示范,2003年开始初花初果,2005年进入盛果期。4个试验点在中等肥水条件下,平均产量2006年1 382.3 kg/667m2、2007年1 555 kg/667m2。可溶性固形物含量高达19%,口感好,品质佳,丰产稳产。从试验结果看,红阳猕猴桃早实、丰产、优质,适宜在贵州类似地区推广。     

不同灌水量对滴灌猕猴桃光合、产量与水分利用效率的影响

【目的】揭示不同灌水量对滴灌猕猴桃生长、产量及水分利用效率的调控效应。【方法】以7 a生"金艳"猕猴桃为试材,在果实膨大期(Ⅲ期)、果实成熟期(Ⅳ期)各设置1个对照(CK)和4个灌水处理,即高水(HW)、中水(MW-1)、偏低水(MW-2)和低水处理(LW),灌水量分别为CK的55%、65%、75%和85%。【结果】猕猴桃叶片光合特性因生育期和灌水量的不同而呈现明显差异,其光合速率(Pn)、蒸腾速率(Tr)和气孔导度(gs)均随灌水量的减小而减小,但Ⅲ-HW、Ⅳ-HW处理的Pn与CK差异不显著(P>0.05),Ⅲ-HW和Ⅳ-MW-2处理的瞬时水分利用效率较CK分别显著提高了2.70%、5.41%(P<0.05);各处理猕猴桃产量较CK仅下降0.09%～6.24%,产量水分利用效率(WUEy)则提高了2.82%～23.16%,其中Ⅲ-HW、Ⅳ-MW-1处理产量仅下降了0.09%、2.45%,而WUEy提高了2.82%、10.73%。【结论】滴灌猕猴桃果实膨大期高水处理、果实成熟期中水处理保持产量无明显下降,有效提高WUEy,并节水2.50%、11.62%(分别节水156、726 m3/hm~2),具有较好的节水稳产效果。     

猕猴桃果实腐烂病的发病规律及药剂筛选试验

采用套袋方法研究了猕猴桃果实腐烂病病菌拟茎点霉(Phomopsis sp.)的侵染规律,采用菌丝生长速率法测定了甲基硫菌灵可湿性粉剂等8种杀菌剂的毒力,结果表明,该菌在谢花后的3周左右开始侵染幼果,6周左右侵染达到高峰;己唑醇微乳剂、咪酰胺锰盐可湿性粉剂对猕猴桃果实腐烂病菌菌丝具有较高的抑制活性,其EC50 分别为0.068、0.105 μg/mL,其次是苯醚甲环唑水分散剂、甲基硫菌灵可湿性粉剂和烯唑醇可湿性粉剂,其EC50 分别为0.224、0.307和0.426 μg/mL,代森锰锌可湿性粉剂、百菌清可湿性粉剂、三唑酮乳油抑制活性较低,其EC50分别为7.862、36.65和99.04μg/ml.     

贵州西部‘红阳’猕猴桃溃疡病与温湿气象条件的联系

为了研究温湿气候变化对‘红阳’猕猴桃溃疡病发生的影响,以‘红阳’猕猴桃为试材,基于2013—2018年贵州猕猴桃主要种植区的水城县猴场、米箩、勺米、六枝特区郎岱、盘州市普古共5个试验区3—4月溃疡病监测资料以及同期温度、湿度、持续降雨日数资料,运用数理统计方法,分析溃疡病发生和流行与温度、湿度、持续降雨日数的联系。结果表明：‘红阳’猕猴桃溃疡病始发的气象条件为持续4天及以上有降水天气（日降水量≥0.1 mm）出现,且日平均温度≤15.0℃、日平均相对湿度≥80%,同时溃疡病始发之后继续维持1天及以上的低温阴雨高湿天气;溃疡病流行的气象条件为持续4天及以上有降水天气（日降水量≥0.1 mm）出现,且日平均温度≤18.0℃、日平均相对湿度≥80%,同时溃疡病流行之后继续维持1天及以上的低温阴雨高湿天气。贵州西部‘红阳’猕猴桃溃疡病的发生、流行对温湿变化有较好的响应。     

Pre-harvest spraying of oxalic acid improves postharvest quality associated with increase in ascorbic acid and regulation of ethanol fermentation in kiwifruit cv. Bruno during storage

The kiwifruit trees (Actinidia deliciosa cv. Bruno) were sprayed with 5 mmol L^–1 oxalic acid (OA) or water (as control) at 130, 137 or 144 d after full-blossom, and then the fruit were harvested at commercial maturity and stored at room temperature (20±1)°C for 13 d. The effect of pre-harvest spraying of OA on postharvest quality of kiwifruit was evaluated during storage. The OA spraying slowed the increase in soluble solids content (SSC) and decrease in titratable acid (TA), as well as increased contents of ascorbic acid (AsA) and total-AsA accompanied with higher AsA/DHA ratio in kiwifruit during storage. Moreover, the OA spraying significantly reduced the contents of acetaldehyde and ethanol in kiwifruit, along with significant decrease in activities of enzymes involved in ethanol fermentation metabolism during the later period of storage, which was beneficial to control off-flavor associated with over accumulation of ethanol during postharvest. It was suggested that pre-harvest spraying of OA might maintain the postharvest quality of kiwifruit in relation to delay in fruit ripening, AsA maintenance and regulation of ethanol fermentation.     

基于栽培管理措施的猕猴桃细菌性溃疡病防治技术

对陕西猕猴桃种植区的栽培管理技术措施与猕猴桃枝干溃疡病发病关系的研究发现,栽培管理措施及水平直接影响溃疡病的发生程度,管理精细的果园发病较轻.为有效控制病害,冬季修剪应在落叶后至元月中旬之间进行;冬灌不能晚于11月底,春灌不早于4月;合理施肥,控制春季萌芽的早晚、伤流的多少和树木生长势,降低病害发生程度.