不同处理对果梅种子萌发的影响

以优选果梅‘黔荔1号’种子为材料,研究赤霉素、低温层积和破壳处理对果梅种子萌发的影响.结果表明:以浓度为50 mg/L的赤霉素溶液浸泡处理,种子发芽率最高,为32％;以150 mg/L赤霉素浸泡果梅种子的适宜时间为30 h;在层积时间内,以层积60 d的果梅种子发芽率最高,可达33％;破壳处理可明显提高果梅种子发芽率,可达47％.     

应用电导率法及Logistic方程测定金光杏梅抗寒性研究

以金光杏梅叶片为试材,分别测定其在5、0、-5、-15、-20℃处理24 h后电解质外渗率,并计算其半致死温度.结果表明:低温处理下,金光杏梅叶片电解质外渗率呈“S”型曲线增长,其半致死温度为-12.09℃.     

Genetic diversity and phylogenetic relationships of Prunus microcarpa C.A. Mey. subsp. tortusa analyzed by simple sequence repeats (SSRs)

Prunus microcarpa C.A. Mey. subsp. tortusa is a deciduous shrub well adapted to severe winter and dry-hot summer conditions. As the first step to explore the genetic and horticultural potential of P. microcarpa C.A. Mey. subsp. tortusa, we used SSRs to elucidate the genetic variation within its populations dispersed in upper Mesopotamia. We also investigated its phylogenetic relationship with economically important Prunus species; almond, apricot, sweet cherry, peach and plums. Using 47 amplifying SSR primer pairs, 63 P. microcarpa C.A. Mey. subsp. tortusa genotypes sampled from five locations and 15 cultivars belonging to other Prunus species were assayed. The cross-species transportability of SSRs was 96% indicating a high degree of homology between P. microcarpa C.A. Mey. subsp. tortusa and the other Prunus species. The genetic distance between P. microcarpa C.A. Mey. subsp. tortusa genotypes belonging to a particular geographic site was lower than that between genotypes of different geographic origins. Cluster analysis differentiated P. microcarpa C.A. Mey. subsp. tortusa genotypes according to their geographic sites and separated them from the other Prunus species. P. microcarpa C.A. Mey. subsp. tortusa and sweet cherry, the subgenus Cerasus, were located in the same major cluster, the other Prunus species, belonging to the subgenera Amygdalus and Prunus, were located in another one. The analysis of molecular variance (AMOVA) revealed that genetic variation among individuals within populations (59.10%) was much higher than among Prunus groups (29.28%) and among P. microcarpa C.A. Mey. subsp. tortusa populations of different geographic sites (11.61%). The results indicate a substantial genetic diversity in P. microcarpa C.A. Mey. subsp. tortusa and the need of exploring a wider area to increase the chance of finding a particular genotype.     

Nitric oxide in combination with indole-3-butyric acid improves root growth in ‘Ferdor Julior’ hardwood cuttings (Prunus insistitia (L.) × Prunus domestica (L.))

The production of plants for high density fruit orchards requires a highly efficient clonal propagation method. ‘Ferdor Julior’ rootstock is well adapted to different soil conditions, but its natural rooting potential is very limited. Propagation treatments, such as bottom heat and indole-3-butyric acid (IBA) applications have previously been used to improve rooting. The aim of this work is to evaluate the effects of either IBA, or sodium nitroprusside (SNP; a nitric oxide (NO) donor), or a combination of both on the rooting of hardwood cuttings of ‘Ferdor Julior’. As metabolism markers, ascorbic acid (AA) and glutathione (GSH) were measured in adventitious roots. ‘Ferdor Julior’ hardwood cuttings were treated as follows: untreated, 0.3 mM IBA, 1 mM SNP, 1 mM SNP previously exposed to light (as a negative control), and 1 mM SNP + 0.3 mM IBA. After 4 months, the combined use of SNP and IBA had increased root growth and lateral rooting, but resulted in less shoot growth, whilst AA and GSH concentrations were also reduced. IBA and SNP individual treatments showed intermediate results, compared to untreated cuttings. According to the results obtained, there may be an additive effect of auxin and NO signaling pathways. In conclusion, this new and promising technique for ‘Ferdor Julior’ propagation could improve lateral root development and promote early lateral root growth.     

Almond Oil Quality as Related to the Type of Pollen Source in Iranian Self Incompatible Cultivars

ABSTRACT

The effects of different pollen sources including five cultivated almond cultivars (Genco, Tuono, 15–5, Filip Ceo, and Supernova) on quantity and quality of chemical composition of two Iranian self-incompatible cultivars (Shahrood 12 and Shahrood 21) as well as self-pollination of these cultivars were investigated. Results showed a variation in oil content and fatty acid composition between two studied cultivars. The oil content was not affected by pollination treatments but the fatty acid composition of almond oil significantly was influenced by type of the pollen source. The most common unsaturated fatty acids found in the kernels of all treatments were oleic acid (68.72–88.26%) and linoleic acid (10.57–22.36%). The type of pollen source with modified oleic/linoleic acid ratio affected the oil quality. The highest oleic/linoleic acid ratio was obtained in Shahrood 12 (8.35%) and Sharood 21 (4.78%) cultivars, which pollinated with Filip Ceo and Supernova pollens, respectively.     

Leaf development,net assimilation and leaf nitrogen concentrations of five Prunus rootstocks in response to root temperature

Rootstocks differentially influence tree physiology and these differences may be due to varying responses to root zone temperature (RZT). To determine if this is the case, the physiology, leaf development and nitrogen relationships of five different Prunus rootstocks with chill requirements between 100 and 1100 h were examined during and after growth at RZTs of 5, 12 and 19 °C for 6 weeks. RZT correlated positively with leaf numbers, expansion rates and final leaf area, and significant differences existed among the rootstocks in the magnitude of these parameters at different RZTs. In particular, leaf expansion and area were less affected at low RZT in the low chill varieties. Net assimilation (A_n), leaf nitrogen (N%) and photosynthetic nitrogen use efficiency (A_n/N) also correlated positively with RZT: again, there were differences in the magnitude of these parameters among the rootstocks. No associations amongst A_n, N% or A_n/N could be found for the rootstocks; hence, they all differed in their physiological responses to RZT. Low RZT alone was sufficient to reduce A_n and decreased both leaf area and photosynthetic activity. Leaf expansion was related to N%, as the varieties with the lowest N% also had the lowest expansion rates. Infrared thermography of the cv. Golden Queen showed a negative correlation between RZT and leaf temperature with leaves of plants at the lowest RZT being 2 °C warmer than ambient whilst those at the highest RZT were 2 °C cooler than ambient. These differences were due to transpiration, as transpiration for the variety used decreased with reducing RZT. Transpiration from the other rootstock varieties was lowest at the 5 °C RZT but, depending on variety, at 12 °C was either higher, lower or the same as that from plants whose roots were at 19 °C. Together, the results of this study explain some of the rootstock-induced changes in tree growth and suggest the need to incorporate seasonal changes in RZT into development models for peaches.     

Evaluation of apricot resistance to Plum pox virus (Sharka) in controlled greenhouse and natural field conditions

In this study we compare the evaluation of Plum pox virus (Sharka) resistance of 29 apricot genotypes in controlled greenhouse conditions by grafting onto infected ‘GF305’ peach seedlings growing in pots, and in natural conditions by grafting onto infected 5-year-old apricot trees growing in the orchard. Apricot genotypes evaluated were initially classified into three groups: susceptible to PPV (presence of PPV symptoms and ELISA positive in greenhouse and field assays), resistant (absence of PPV symptoms and ELISA negative in both assays) and undetermined (evaluated differently in both assays). Results showed a similar behavior against Plum pox virus in both assays in 20 out of the 29 apricot genotypes studied (69%). However, in the other nine genotypes results were different (31%). Evaluation in field was more accurate, detecting a higher number of susceptible genotypes, probably due to the higher inoculation pressure in the old trees in comparison with the GF305 rootstocks in pots. However, greenhouse evaluation let to work in controlled isolated conditions with a higher number of genotypes. This situation is greatly required in areas where Sharka is not widely spread. Greenhouse evaluation could be then the first screening method to evaluate Plum pox virus resistance of apricot genotypes, and could be complemented with the evaluation onto infected trees in natural conditions in insect-proof quarantine shelter.     

Thinning time during stage I and fruit spacing influences fruit size of ‘Contender’ peach

Early peach thinning during stage I was done at 0, 10, 20, 30, and 40 days after full bloom (DAFB). At each thinning time, trees were hand-thinned to achieve different crop loads by spacing flowers or fruits 10, 15, or 25 cm along the shoot on whole tree canopies. In 2001 and 2002, fruit weight decreased quadratically with increasing time to hand-thin and increased linearly with increasing spacing. In both years, fruit diameter decreased linearly with increasing time to thin and increased linearly with increased fruit spacing. In both years, number of fruits harvested and yield per tree decreased linearly with increased spacing. Hand-thinning at 0 or 10 DAFB resulted in fewer fruit and lower yield; therefore, thinning at 20 DAFB was better. The effect of time of thinning on soluble solids was not consistent. In both years spacing (i.e., crop load) did not affect soluble solids.     

Spatial spread of an alien tree species in a heterogeneous forest landscape: a spatially realistic simulation model

The effect of environmental heterogeneity on spatial spread of invasive species has received little attention in the literature. Altering landscape heterogeneity may be a suitable strategy to control invaders in man-made landscapes. We use a population-based, spatially realistic matrix model to explore mechanisms underlying the observed invasion patterns of an alien tree species, Prunus serotina Ehrh., in a heterogeneous managed forest. By altering several parameters in the simulation, we test for various hypotheses regarding the role of several mechanisms on invasion dynamics, including spatial heterogeneity, seed dispersers, site of first introduction, large-scale natural disturbances, and forest management. We observe that landscape heterogeneity makes the invasion highly directional resulting from two mechanisms: (1) irregular jumps, which occur rarely via long-distance dispersers and create new founder populations in distant suitable areas, and (2) regular, continuous diffusion toward adjacent cells via short- and mid-distance vectors. At the landscape scale, spatial heterogeneity increases the invasion speed but decreases the final invasion extent. Hence, natural disturbances (such as severe storms) appear to facilitate invasion spread, while forest management can have contrasting effects such as decreasing invasibility at the stand scale by increasing the proportion of light interception at the canopy level. The site of initial introduction influences the invasion process but without altering the final outcome. Our model represents the real landscape and incorporates the range of dispersal modes, making it a powerful tool to explore the interactions between environmental heterogeneity and invasion dynamics, as well as for managing plant invaders. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

李种质资源ISSR鉴定及亲缘关系分析

为了更好的利用目前收集得到的李资源,对重庆地方李品系和国内外引进的李品种共40份资源进行了ISSR分析。从100条引物中筛选出13条多态性引物,共扩增得到134条带,多态性条带109条,多态性百分率为81.3%,其中9条特征性谱带可用于品种鉴定和系谱分析的参考性标记。此外,13条引物可将40份材料完全区分开来,图谱分析表明不存在同物异名现象。UPGMA聚类分析将供试品种分成2组,进一步可细分为4个亚组;主坐标分析将其分成6类,其中奉节李、脆红李和万盛鸡血李分别单独成类。2种分析方法所得的结果均与按原产地划分的结果不完全相符,奉节李、脆红李和万盛鸡血李与其余品种(品系)的亲缘关系较远。来自江苏的早黄李与日本和美国李品种间的亲缘关系相对较近,初步推测国外中国李可能来源于我国华东地区。