萝卜种子萌发的逆温耐性诱导研究

以萝卜种子为试材,研究不同温度预处理对萌发期萝卜种子逆温耐性的影响。结果表明:萝卜种子在低于15℃和高于35℃下萌发,种子活力显著下降,而通过适度的温度胁迫处理,可提高萝卜种子在高温（35℃）下的萌发活力。15℃和25℃分别是预处理的适宜低温和高温,6 h是低温（15℃）预处理的适宜时间。萝卜种子经高温（30℃）预处理12 h后,在随后的低温（10℃）下萌发,也提高其种子活力,说明萝卜种子对高温和低温胁迫具有交叉适应性。     

An ACCUMULATION AND REPLICATION OF CHLOROPLASTS 5 gene mutation confers light green peel in cucumber

The peel color of fruit is an important commercial trait in cucumber,but the underlying molecular basis is largely unknown.A mutant showing light green exocarp was discovered from ethyl methane sulfonate(EMS) mutagenized cucumber line 406 with dark green exocarp.Genetic analysis showed the mutant phenotype is conferred by a single recessive gene,here designated as lgp(light green peel).By re-sequencing of bulked segregants,we identified the candidate gene Csa7Go51430 encoding ACCUMULATION AND REPLICATION OF CHLOROPLASTS 5(ARC5) that plays a vital role in chloroplast division in Arabidopsis.A single nucleotide polymorphism(SNP) causing amino acid alteration in the conserved GTPase domain of Csa7G051430 showed co-segregation with the altered phenotype.Furthermore,the transient RNA interference of this gene resulted in reduced number and enlarged size of chloroplasts,which were also observed in the Igp mutant.This evidence supports that the non-synonymous SNP in Csa7G051430 is the causative mutation for the light green peel.This study provides a new allele for cucumber breeding for light green fruits and additional resource for the study of chloroplast development.     

胭脂萝卜红色素的研制

本文报道了胭脂萝卜红色素的生产工艺,并结合生产方法与相关条件开展讨论。同时报道了胭脂萝卜红色素的三种物理性状,即溶解性、坚牢度、染着性     

Interaction Between Root and Leaf Disease Development in Barley Cultivars after Inoculation with Different Isolates of Bipolaris sorokiniana

The relationship between root and leaf infection in 11 cultivars of barley ( Hordeum vulgare ) by different isolates of Bipolaris sorokiniana was investigated in young plants. Roots of 10-day-old seedlings, grown in filterpaper rolls, and the third leaf of 17-day-old seedlings were inoculated with the different isolates and a Disease Development Index (DDI) was calculated.
The rate of lesion development in leaves was higher than in roots, indicated by generally higher DDI after leaf inoculation than after root inoculation. Significant differences in resistance were found among the barley cultivars. Inoculation with different isolates of B. sorokiniana caused significant differences in DDI for both roots and leaves. In the leaves, but not in the roots, a significant cultivar–isolate interaction was found. No significant correlations, neither in isolate aggressiveness nor in cultivar reaction between root and leaf, were observed.     

Silicon uptake and transport is an active process in Cucumis sativus

Cucumis sativus is a species known to accumulate high levels of silicon (Si) in the tops, though the mechanism for its high Si uptake is little understood. In a series of hydroponic experiments, we examined uptake and xylem loading of Si in C. sativus along with Vicia faba at three levels of Si (0.085, 0.17 and 1.70 mm). Measured Si uptake in C. sativus was more than twice as high as calculated from the rate of transpiration assuming no discrimination between silicic acid and water in uptake. Measured Si uptake in V. faba, however, was significantly lower than the calculated uptake. Concentration of Si in xylem exudates was several-fold higher in C. sativus, but was significantly lower in V. faba compared with the Si concentration in external solutions, regardless of Si levels. Silicon uptake was strongly inhibited by low temperature and 2,4-dinitrophenol, a metabolic inhibitor, in C. sativus but not in V. faba. It can be concluded that Si uptake and transport in C. sativus is active and independent of external Si concentrations, in contrast to the process in V. faba.     

Microsatellite Markers Associated with Spot Blotch Resistance in Spring Wheat

Spot blotch, caused by Cochliobolus sativus, is a serious wheat (Triticum aestivum L.) disease in the warm areas of South Asia. Breeding for resistance in the past 15 years has produced limited progress, and newly developed wheat cultivars suffer considerable yield reductions under spot blotch epidemics in the region. Resistance is often controlled by multiple genes with additive effects. Marker‐assisted selection, in combination with field selection, could accelerate the identification of progeny with multiple genes for resistance early in the breeding process. A study was conducted to determine microsatellite markers associated with resistance in the F₇ progeny from a cross between the spot blotch‐susceptible Sonalika and resistant G162 wheat genotypes. A parental survey using 171 simple sequence repeats (SSR) primer sets and spread over 21 chromosomes of wheat identified 52% polymorphic loci. However, only 15 polymorphic markers showed association with two bulks, one each of progeny with low and with high spot blotch severity. The detailed analysis indicated that progeny lines with low spot blotch severity could be separated from those with high severity using three SSR markers located on three wheat chromosomes. The findings may be useful in developing a marker‐assisted selection strategy for spot blotch resistance in wheat.     

A Method for Purifying Cochliobolus sativus Cultures Contaminated with Bacteria

A simple method was developed for purifying Cochliobolus sativus cultures contaminated with bacteria. In this method the contaminated fungal culture is scraped from the surface of the potato dextrose agar (PDA) growth medium. Small leaf pieces (approximately 0.5 cm) of a highly susceptible genotype of barley were placed on the scraped surface of PDA and incubated for 72 h. Disease symptoms of C. sativus were detected on the leaf pieces. Colonies that developed from these pieces on new PDA medium were free from bacteria.     

CsSPL functions as an adaptor between HD‐ZIP III and CsWUS transcription factors regulating anther and ovule development in Cucumis sativus (cucumber)

Anther and ovule genesis preconditions crop fertilization and fruit production; however, coordinative regulation of anther and ovule development and underlying molecular pathways remain largely elusive. Here, we found that SPOROCYTELESS (SPL)/NOZZLE (NZZ) expression was nearly abolished in a Cucumis sativus (cucumber) mutant with severely defective anther and ovule development. CsSPL was expressed specifically in the developing anthers and ovules. Knock‐down of CsSPL reduced male and female fertility with malformed pollen and suppressed ovule development. Importantly, CsSPL directly interacted with CsWUS (WUSCHEL) in the nucellus and YABBY family genes in integuments, and positively regulated CsWUS expression, meanwhile the HD‐ZIP III gene CsPHB (PHABULOSA), expressed specifically in the nucellus, promoted CsSPL expression by binding to the CsSPL promoter. Thus, CsSPL acts as an adaptor to link CsPHB and CsWUS functioning, underpinning a previously unidentified regulatory pathway orchestrating sex organ development in planta. In addition, auxin accumulation was reduced in the reproductive organs of CsSPL knock‐down plants. Biochemical analyses further showed that CsSPL stimulated the expression of AUXIN RESPONSE FACTOR 3 (CsARF3), and was positively regulated by CsARF13 during reproductive organ development, indicating sequential interactions of CsSPL with auxin signaling components in orchestrating anther and ovule development.