我国几个不同地域长梗扁桃苗木的抗寒性研究

分别取自河北、固阳、神木、榆林、乌审旗5地生长状况基本相同的长梗扁桃1年生休眠枝条为材料,通过人工冷冻模拟外界环境,对长梗扁桃枝条进行-15℃、-19℃、-23℃、-27℃、-31℃、-35℃、-39℃等7个温度梯度处理.测得这些休眠枝条的相对电导率、SOD、POD活性、游离脯氨酸含量及MDA含量,并对低温处理过的部分枝条进行恢复生长来测定其萌芽率,最后对测定结果进行分析和比较.结果表明:5个地区的长梗扁桃的相对电导率、SOD、POD活性、游离脯氨酸含量及MDA含量均随着处理温度的降低而呈现上升趋势,并且抗寒性强的地区的长梗扁桃SOD、POD活性和游离脯氨酸含量相对较高,MDA含量和电导率较低,恢复生长枝条的萌芽率均比同温度处理下的抗寒性弱的高.抗寒性强弱顺序为:河北(H)＞乌审旗(W)＞固阳(G)＞神木(S)＞榆林(Y),河北和乌审旗的长梗扁桃抗寒性较强,可以对其进行广泛的品种选育和推广.     

桃幼胚下胚轴高频植株离体再生

以桃品种京艳和晚蜜不同发育阶段合子胚下胚轴为外植体进行离体培养,用6-BA、CPPU和TDZ等细胞分裂素诱导下胚轴直接再生不定芽试验。结果表明,花后70d下胚轴为诱导的最佳材料,供试细胞分裂素中,诱导活性为TDZ>CPPU>6-BA,苯脲类细胞分裂素TDZ5mg/L与NAA0.01mg/L配合对下胚轴再生具有极强的诱导作用,京艳诱导再生率高达95.2%,平均不定芽数达每外植体25.3个。京艳的诱导率显著高于晚蜜。IBA 0.5mg/L适于诱导再生幼茎的生根,生根率和移栽成活率分别达到92.6%和65.5%。组织学观察表明不定芽起源于皮层薄壁细胞,属直接再生方式。     

桃、李属红叶树种叶片光合特性

以紫叶桃、紫叶李、美人梅及紫叶矮樱4种红叶树种为试材,油蟠桃和玉皇李2种绿叶树种为对照,测定其色素含量、反射光谱、光合速率日变化及相关荧光参数.结果表明:红叶树种花青苷的含量显著高于绿叶树种,除美人梅外,叶绿素、类胡萝卜素的含量红叶与绿叶树种无显著差异.红叶和绿叶树种净光合速率日变化均为双峰曲线,均存在光合"午休"现象,但红叶树种的净光合速率低于绿叶树种,且光合"午休"持续时间较绿叶树种短.从叶绿素荧光参数日变化来看,红叶树种与绿叶树种PSⅡ最大光化学效率(Fv/Fm)差异不大,红叶树种实际光化学效率(ФPSⅡ)、光化学猝灭系数(qp)低于绿叶树种,非光化学猝灭系数(NPQ)高于绿叶树种,热耗散能力较强.     

3个扁桃品种的光合特性

在盆栽条件下对3个引种扁桃品种3#、4#和7#的光合作用、荧光参数生理生态特点进行研究.结果表明: 1)扁桃叶片的净光合速率(Pn)日变化均呈双峰曲线型,峰值在10:00,次峰值在16:00,10:00-15:00有"午休"现象;在10:00-15:00时4#和7#叶片的Pn显著高于3#,15:00差值最大.2)扁桃不同品种的光合生理生态参数有显著差异: 4# 的光饱和点和补偿点都比3#和7#高,分别为1 206 μmol·m-2s-1和25.82 μmol·m-2 s-1,说明4#品种能适应较高的光照强度;4#和7# 的CO2补偿点和饱和点都比3#高,扁桃在CO2饱和点以下,Pn随CO2浓度的增加呈线性增长,说明增大CO2浓度可大大提高光合生产力.3)叶绿素荧光参数的日变化显示: 4#和7#的Fv/Fm、光化学猝灭系数(qP)均高,且正午过后Fv/Fm恢复较快,不仅能较强地吸收光能,同时还具有较高的PSⅡ活性和光能转化效率,从而将所吸收的光能有效地转化为化学能,提高光合电子传递速率,形成更多的ATP和NADPH,为光合碳同化提供充分的能量和还原能力.     

桃MRLK家族全基因组鉴定及蚜虫侵染后的表达分析

以Malectin(PF11721)、Malectin-like(PF12819)和Pkinase(PF07714)保守域全蛋白序列为种子序列,鉴定桃(Prunus persica)基因组中全部MRLK类受体激酶(Malectin receptor-like kinases)家族成员,并利用转录组测序分析桃绿蚜侵染不同时间MRLK在抗蚜和感蚜品系材料中的表达情况。利用生物信息学手段进行分析,共获得41个MRLK家族成员,这些基因分布在桃的8条染色体上。家族成员氨基酸数量介于391～1 035 aa,分子量44.05～115.09 kD,等电点5.38～9.16。分析系统进化树发现拟南芥、水稻和桃的MRLK家族分为5个亚组,其中桃MRLK家族成员分布在Ⅰ、Ⅱ和Ⅲ亚组上。亚细胞定位预测显示该家族成员全部定位在细胞膜上。顺式作用元件预测结果显示该家族成员启动子包含光、激素以及响应生物与非生物胁迫的作用元件。桃绿蚜侵染结果表明,桃MRLK家族中19个基因在5个桃材料中均未表达,15个基因在抗蚜品系‘P5868’与其他4个材料之间无差异表达。Pp MRLK2、Pp MRLK9、Pp MRLK22...     

基于HSV空间和拟合椭圆的光核桃种核表型自动量化系统构建

针对现有青藏高原光核桃种核表型主要采用手工测量和目视法获得,操作繁琐,且提取参数种类有限的问题,该研究构建了一种基于HSV（Hue,Saturation,Value）空间和拟合椭圆的光核桃种核表型自动量化系统。该系统包括图像自动分割和多重参数提取2个部分,首先,采用HSV阈值法实现光核桃种核图像的精准分割;其次,用拟合椭圆法进行光核桃种核的核尖提取;最后,对光核桃种核形态、颜色、纹理3类表型进行定量描述。结果表明,该系统对光核桃种核的自动分割准确率达到99.7%,且能够实现多种表型的自动、准确量化,为光核桃表型参数研究提供数据基础和技术支持。     

土壤水分对长柄扁桃生长特性及蒸散发的影响

以1年生长柄扁桃幼苗为材料,通过盆栽控水试验的方法,设置土壤含水量分别为田间持水量的50%~75%（轻度干旱胁迫）、75%~100%（对照）和100%~125%（水涝胁迫）,研究不同土壤水分胁迫对长柄扁桃幼苗生长特性及蒸散耗水规律的影响。结果表明,水分胁迫对长柄扁桃幼苗生长及蒸散耗水具有明显影响,长柄扁桃蒸散耗水量随水分胁迫程度的加剧呈下降趋势。轻度水分胁迫有利于长柄扁桃株高、基径、叶面积及新枝数的生长,但叶片衰老较快。水涝胁迫在一定程度上有利于长柄扁桃叶面积及基径的生长并能减缓叶片衰老,但不利于株高及新枝数的增加。综合分析认为,轻度水分胁迫是长柄扁桃幼苗生长的适宜土壤水分含量。     

Next generation sequencing reveals the potential functions of the genes involved in controlling several important commercial traits in peach (Prunus persica (L). Batsch) fruits

Next-generation sequencing techniques provide a new insight into the genetic bases of the most important commercial traits in fruit trees. The genomic deep sequencing results of peach cultivar ‘Xiaobaitao’ and its bud variation type ‘Jinliuzaohong’ are reported here. The numbers of detected Single nucleotide polymorphisms (SNPs) in wild type and in mutant were 591,485 and 593,484, with that of InDel as 113,934 and 115,065, respectively. Interestingly, the numbers of SNPs and InDels that differentiate ‘Jinliuzaohong’ from ‘Xiaobaitao’ were 50,217 and 19,368, respectively. The number of genes with non-synonymous mutation was 887, which involved in 109 pathways. The authors found dozens of genes involved in the important commercial traits of peach fruit which are of variations in Coding sequence (CDS) regions, including 3 NAC family genes, i.e. NAC66, NAC68, and NAC78. The relevant commercial traits of peach fruit include colour coverage, maturity date, fruit size, and sugar content. A phylogenetic tree of homological NAC proteins indicated relationship among the species. Genome sequence data suggested that a series of genes and several genetic pathways were likely involved in the formation of the important traits in peach fruits. The findings provide new evidence for the functions of the candidate genes controlling peach fruit traits which were proposed previously by researchers using QTL analysis.     

不同浓度1-MCP处理对“朝霞”水蜜桃果实的保鲜效应

研究不同浓度(0、0.3、0.6、0.9、1.2、1.5、1.8μL/L)的纸片型1-甲基环丙烯(1-MCP)处理对“朝霞”水蜜桃果实在(25±1)℃贮藏条件下的保鲜效应。结果表明:与未处理的对照组果实相比,不同浓度1-MCP处理的“朝霞”水蜜桃果实均具有较低的果实呼吸强度和细胞膜相对渗透率,较高的果皮色调角h°、果实硬度、果肉可溶性固形物、可滴定酸含量和果实好果率,较低的果实腐烂率、病害指数和失重率,进而保持水蜜桃果实较好的采后贮藏品质。其中,1.2μL/L 1-MCP处理效果最佳。因此认为,浓度为1.2μL/L的纸片型1-MCP处理可作为在(25±1)℃条件下贮藏采后“朝霞”水蜜桃果实的适宜条件。     

COPPER EFFECTS ON PRUNUS PERSICA IN TWO DIFFERENT GRAFTING COMBINATIONS (P. PERSICA × P. AMYGDALUS AND P. CERASIFERA)

Growth, chlorophyll content, biomass dry weight (DW), nutrient uptake and copper (Cu) accumulation were evaluated in BigTop® peach (Prunus persica L. Batsch) grafted onto two different rootstocks [GF677 (P. persica × P. amygdalus) and Mr.S2/5 (P. cerasifera)] when grown in the presence of 0.1, 10 or 100 μM copper sulfate (CuSO₄). Although scion shoot length varied significantly in response to Cu concentration only with Mr.S2/5 rootstock (40%reduction at 100 μM Cu compared with control), Cu concentration in the scion grafted on GF677 was higher (18.2 mg kg^?1) compared to that grafted on Mr.S2/5 (10.5 mg kg^?1). In both graft combinations, the Cu concentrations in leaves were not statistically different although values ranged between 4.7 and 8.1 mg kg^?1. The DW of leaves and stems was not statistically different from control plants in both graft combinations. On the contrary, root DW of Mr.S2/5 increased, about 13% at 10 μM Cu and 43% at 100 μM Cu. In contrast, DW of GF677 roots at higher Cu treatment was significant lower than control. Chlorophyll reduction Cu induced was not found, suggesting that the degradation of these pigments is maintained at low levels. The uptake of sodium (Na), zinc (Zn), and iron (Fe) changed during Cu stress. The different behavior observed between GF677 and Mr.S2/5 regarding Cu accumulation proves that these two rootstocks have a different ability in translocation and accumulation of Cu in presence of this heavy metal. The use of GF677 rootstocks, in substrates particularly rich of Cu, insures a better development of scion growth when compared to Mr.S2/5, but determines a higher Cu concentration in the stem, while Mr.S2/5 seems to be able to stabilize the Cu concentrations in the scion.