The deleterious effects of salinity stress on leafminers and their freshwater host

Abstract.  1. Salinity is an important cause of abiotic stress in wetland communities yet little is known about its consequences for freshwater plants and their insect herbivores. The goal of this study was to test the effect of salinity on a leafmining insect, Cerodontha iridiphora , and its herbaceous host plant, Iris hexagona .
2. Leafminer performance was evaluated on irises grown in control and saline treatments, and the effects of salinity and herbivory on leaf quality and mortality was measured.
3. Leafminer density and size were significantly lower on irises grown in saline water compared with freshwater.
4. Both salinity and herbivory accelerated leaf senescence and mortality, and their combined effects increased tissue loss by an order of magnitude compared with controls.
5. Leafminers acted as nutrient sinks. The undamaged regions of mined leaves contained 40% less nitrogen than unmined leaves, providing a mechanism for the premature leaf mortality.
6. Salinity was detrimental to the performance and survival of both the iris leafminer and its host plant. We propose that glycophytic host plants and their insect herbivores will suffer more than halophytic communities from environmental salinity because they lack the adaptive mechanisms to tolerate this potent physiological stress.     

马蔺对不同浓度NaHCO3胁迫的生理响应

为探讨不同浓度NaHCO₃胁迫下,马蔺叶片的膜透性、可溶性蛋白及膜脂过氧化物含量的变化规律,以1年生马蔺实生苗为研究对象,通过对细胞膜透性、膜质过氧化产物MDA、SOD、POD和可溶性蛋白等指标进行测定,研究在盆栽控盐条件下,马蔺对NaHCO₃胁迫的适应与响应。结果表明：随着NaHCO₃浓度和胁迫时间的增加,对马蔺叶片可溶性蛋白含量的影响总体是先下降后上升的趋势,在30 d时,0.4%和0.6%盐浓度胁迫下的马蔺的可溶性蛋白含量上升较大,分别比对照高：21.7%,38.6%;在NaHCO₃盐胁迫的10~20 d,马蔺叶片的的膜透性略有降低;在20~30 d时,膜透性迅速上升;NaHCO₃胁迫20 d时,除对照外其他盐浓度胁迫下的马蔺叶片的POD活性都达到了最大值,分别比对照高95%,103%,496%;相同盐浓度胁迫下,随着时间的延长,SOD活性变化趋势是先下降后上升;MDA作为膜脂过氧化作用的主要产物之一,随着盐浓度的增加和盐胁迫时间的延长,在30d时0.6%浓度的马蔺叶片中MDA含量大量积累。综上所述,马蔺有抗盐（NaHCO₃）胁迫的能力,是重要的盐碱地生植物,本研究为马蔺的抗盐碱性研究又提供了一有力证据,同时为今后将马蔺应用于治理盐碱土地增加了理论基础。     

An alternative method for irones quantification in iris rhizomes using headspace solid-phase microextraction

Introduction – The essential oil obtained from iris rhizomes is one of the most precious raw materials for the perfume industry. Its fragrance is due to irones that are gradually formed by oxidative degradation of iridals during rhizome ageing. Objective – The development of an alternative method allowing irone quantification in iris rhizomes using HS‐SPME‐GC. Methodology – The development of the method using HS‐SPME‐GC was achieved using the results obtained from a conventional method, i.e. a solid–liquid extraction (SLE) followed by irone quantification by CG. Results – Among several calibration methods tested, internal calibration gave the best results and was the least sensitive to the matrix effect. The proposed method using HS‐SPME‐GC is as accurate and reproducible as the conventional one using SLE. These two methods were used to monitor and compare irone concentrations in iris rhizomes that had been stored for 6 months to 9 years. Conclusion – Irone quantification in iris rhizome can be achieved using HS‐SPME‐GC. This method can thus be used for the quality control of the iris rhizomes. It offers the advantage of combining extraction and analysis with an automated device and thus allows a large number of rhizome batches to be analysed and compared in a limited amount of time. Copyright © 2010 John Wiley & Sons, Ltd.     

鸢尾属药用植物总DNA提取方法的比较研究

以鸢尾属（Iris L．）药用植物鸢尾Iris tectorum Maxim．叶片为材料,分别采用CTAB法、高盐低pH法、SDS法和试剂盒法四种方法提取植物总DNA,并通过琼脂糖凝胶电泳、紫外分光光度计、ISSR和RAPD四种方法对所提取的DNA样品进行检测。结果表明,用SDS—I法提取的植物总DNA纯度、浓度和完整性都很高,从经济角度考虑优于用试剂盒提取,从提取效果考虑不亚于用CTAB法和高盐低pH法提取,是比较适合鸢尾属植物总DNA提取的方法。     

Antiplasmodial and antifungal activities of iridal,a plant triterpenoid

Iridal, a triterpenoidic compound extracted from Iris germanica L., was previously shown to have an interesting activity on two cultured human tumor cell lines (A2780 and K562). In the present work, this same product was tested in vitro on Plasmodium falciparum chloroquine-resistant and -sensitive strains, in vivo on P. vinckei, and on some Candida albicans and C. parapsilosis strains too. The IC(50) obtained in vitro on human malaria strain ranged from 1.8 to 26.0 microg/ml and the ED(50) in vivo is about 85 mg/kg/day by intraperitoneal route. The minimal inhibitory concentrations were higher than to 50 microg/ml, whatever the strain of yeast tested. This product presents an antiplasmodial activity similar to that obtained with extracts from the plant Azadirachta indica classically taken as reference in malaria phytomedicine. Conversely iridal shows no important antifungal activity. The specific activity of iridal on human malaria parasite and on tumor cell lines is discussed.     

Patterns of genetic and phenotypic variation in Iris haynei and I. atrofusca (Iris sect. Oncocyclus = the royal irises) along an ecogeographical gradient in Israel and the West Bank

Iris haynei and I. atrofusca are two closely related narrow endemics distributed vicariously along an ecogeographical north-south gradient in Israel and the West Bank. To obtain baseline information of the taxonomic status, conservation and population history of these taxa, we investigated patterns of phenotypic variation and the partitioning of genetic variation within and among populations using dominant random amplified polymorphic DNA (RAPD) markers. Multivariate (principal components analysis) and taxonomic distance analyses based on morphometric traits from eight populations revealed no unambiguous separation into two distinct groups. Results of genetic analyses for nine populations differed only slightly when either allele- or marker-based approaches were employed. Mean within-population diversity was high (0.258 for Nei's expected heterozygosity), but there was no significant relationship between genetic diversity and either population size or latitude. Although the range-wide estimate of GST ( approximately 0.20) revealed relatively high differentiation among populations this value was inflated because of a small, but significant, component of molecular variance among regions viz. taxa ( approximately 5%). Limited long-distance dispersal capabilities in conjunction with a linearized habitat distribution are proposed to contribute to the approximate isolation by distance pattern observed. It also appears that extant populations are currently deviating from equilibrium conditions because of primary divergence of a formerly more widespread ancestral population. Given the absence of deep genetic and phenotypic subdivision among northern (I. haynei) vs. central/southern (I. atrofusca) populations, we argue for a revision of their species status. Nonetheless, we recommend conservation attention to these geographically differentiated segments as separate management units, which can be seen as an instructive example of incipient species formation.     

Alkylated benzoquinones from Iris kumaonensis

Six novel alkylated p-Benzoquinones irisoquin (A-F) (1-2, 4-7) together with a known cytotoxic quinone, irisoquin (3) along with three known isoflavones, tectoregenin, iristectorin and irigenin were isolated from the rhizomes of Iris kumaonensis and characterized. The structures of compounds 1-2, 4-7 were confirmed by extensive spectroscopic analysis, IR, MS, HRMS, GC, GC-MS, 1D (1H, 13C, NOE) and 2D (HMQC and HMBC) NMR and comparison with literature data of known compounds.     

Disease development of Pythium root rot in bulbous Iris and Crocus

Iris bulbs and Crocus corms were planted at two planting dates in sandy soil infested with Pythium spp. At monthly intervals during the growing season root rot infection was assessed over 3 consecutive years and disease development curves were predicted for both crops. The disease development was remarkably different for Iris and Crocus and the curve shape was determined by the crop rather than by the Pythium species. Planting date had a significant effect on disease development in both crops. No correlation was found between disease development and soil temperature.     

Stress-induced male sterility and mixed mating in the island plantCedronella canariensis (Lamiaceae)

Reaction norms were determined in two natural populations of the perennial plantIris pumila from contrasting light conditions at two levels of photosynthetically active radiation (105 and 35 µmol m^–2s^–1). Seedlings developed from free-pollinated seed families sampled individually from 19 and 12 randomly selected clonal genotypes in an exposed and a shaded population respectively, were grown in a growth room using a mixed model nested factorial experimental design and scored for a number of phenological and morphological traits. Ambient light conditions significantly affected all of the juvenile traits measured. In both populations, relatively convergent norms of reactions were revealed for leaf appearance dates, as well as for leaf number, suggesting the importance of these traits for functional adjustment to prevailing light conditions. Reaction norms for morphological traits, however, were largely nonparallel, but although often crossing each other, a significant family-by-treatment interaction in the ANCOVAs performed was not detected for any of the traits measured, indicating a small amount of genetic variation for plasticity in these populations. The extent of plastic response to light availability was determined and expressed as an index that estimates the percentage change in a trait value from a high to a low light level. Evolutionary and ecological implications of the observed plastic variations are also discussed.