Senescence-related gene expression profiles of rosette leaves of Arabidopsis thaliana: leaf age versus plant age

Abstract: Senescence is a form of programmed cell death (PCD) which leads to the death of whole organs, e.g., leaves or flowers, and eventually to the death of entire plants. Like all forms of PCD, senescence is a highly regulated and energy consuming process. Senescence parameters, like protein content, chlorophyll content, expression of photosynthesis-associated genes or senescence-associated genes (SAGs), reveal that senescence occurs in old leaves derived from young plants (6 week old) as well as in young leaves derived from older plants (8 week old), indicating that it is governed by the actual age of the leaves. In order to analyse the differential gene expression profiles during leaf senescence, hybridizations of high-density genome arrays were performed with: i) individual leaves within the rosette of a 6-week-old plant and ii) leaves of the same position within the rosette but harvested from plants of different ages, ranging from 5 to 8 weeks. Cluster and genetree analyses, according to the expression pattern revealed that genes which are up-regulated with respect to the age of the entire plant, showed completely different expression profiles with respect to the age of the individual leaves within one rosette. This was observed even though the actual difference in leaf age was approximately the same. This indicates that gene expression appears to be governed by different parameters: i) the age of the individual leaf and ii) the age and developmental stage of the entire plant.     

Flavones and anthocyanins from the leaves and flowers of Japanese Ajuga species (Lamiaceae)

Flavones and anthocyanins were isolated from the leaves and flowers of 14 Ajuga taxa (Lamiaceae), which are all native or naturalized in Japan. Of 13 flavones obtained from the leaves, 11 were characterized as apigenin, luteolin, 6-hydroxyluteolin and acacetin glycosides. Ten flavones were isolated from the flowers. Ten anthocyanins were isolated from the flowers. Six of these anthocyanins were identified as acylated delphinidin glycosides and four were shown to be acylated cyanidin glycosides. Japanese Ajuga taxa were chemotaxonomically discussed by their distribution patterns, especially foliar flavonoids.     

Composition of epiphytic bacterial communities differs on petals and leaves

The epiphytic bacterial communities colonising roots and leaves have been described for many plant species. In contrast, microbiologists have rarely considered flowers of naturally growing plants. We identified bacteria isolated from the surface of petals and leaves of two plant species, Saponaria officinalis (Caryophyllaceae) and Lotus corniculatus (Fabaceae). The bacterial diversity was much lower on petals than on leaves of the same plants. Moreover, the bacterial communities differed strongly in composition: while Pseudomonadaceae and Microbacteriaceae were the most abundant families on leaves, Enterobacteriaceae dominated the floral communities. We hypothesise that antibacterial floral volatiles trigger the low diversity on petals, which is supported by agar diffusion assays using substances emitted by flowers and leaves of S. officinalis. These results suggest that bacteria should be included in the interpretation of floral traits, and possible effects of bacteria on pollination are proposed and discussed.     

A forgotten collection: the Libyan ethnobotanical exhibits (1912-14) by A. Trotter at the Museum O. Comes at the University Federico II in Naples, Italy

Background

The Ethnobotanical Collection from the Libyan territories of the botanist Alessandro Trotter is included in the Oratio Comes Botanical Museum at the Faculty of Agraria at the University Federico II in Naples. Trotter explored different territories of Libya, mainly Tripolitania, between 1912-1924, collecting plant specimens and the drugs most frequently sold in the markets. The Libyan herbarium currently includes over 2300 sheets of mounted and accessioned plants. The drugs, mostly acquired by Trotter from Tripolitanian markets, were identified and packed in 87 paper sheets or boxes. Trotter added ethnobotanical information for each species when available.

Methods

A database of the herbarium species and the drugs has been carried out, after a taxonomic update. Nomenclature has been revised according to the African flowering plants database and the World Checklist of selected plant families, and a comparison with currently available ethnopharmacological data from North African has been attempted.

Results

In this study, ethnopharmacological data related to about 80 species of flowering plants and to 4 lichens are presented. The plants are mainly from Mediterranean or Sub-Saharan habitats and belong to 37 different families; Lamiaceae was the most cited family, with 10 accessions. Generally, the aerial parts of the plants are the most frequently used (28 species), followed by leaves (15 species), flowers and seeds (9 species), fruits (7 species) and hypogean organs (roots, rhizomes, tubers: 5 species). Plants were generally processed in very simple ways: infusion or decoction of the plants were prepared and orally administered or used for topical applications. A wide range of conditions was treated, ranging from mental disorders to skin affections. All the organs of human body are considered, but the pathologies of gastro-intestinal tract, respiratory system and those related to traumatic accidents were the most frequently mentioned. The comparison with the recent ethnopharmacological research in Maghreb and its neighboring countries reveals a high correspondence; almost all the plants cited by Trotter are still used in the folk medicine of at least one of the North African countries, and the therapeutic uses of each plant appear consistent over time.

Conclusions

The information collected by Trotter is an important contribution to tracing plant utilization in Libyan folk medicine over the last century.     

Antifungal activity of essential oils from leaves and flowers of Inula viscosa (Asteraceae) by Apulian region

Some essential oils from several plants (Artemisia verlotorum, Lavandula augustifolia, Ocimum gratissimum) have proved to have acaricidal, antifungal and antibacterial activity. Inula viscosa Ait. (Asteraceae), a plant growing spontaneously in the Mediterranean area, is currently used by popular medicine for its therapeutic effects. Flavonoids, azulenes, sesquiterpenes, and essential oils have been isolated and identified from its leaves. This paper reports the results of the composition and antifungal activity in vitro against dermatophytes and Candida spp. of the four essential oils obtained by steam distillation of the leaves, flowers, whole plant and whole plants without flower extracts of I. viscosa. All the extracts proved to have a significant antifungal activity against dermatophytes even at low concentrations (0.01 mg/ml). The leaf extracts exhibited the greatest antifungal efficacy. The high concentration of the sesquiterpene (carboxyeudesmadiene), occurring in the leaf extracts, may explain its greater antifungal activity.     

Blue light controls solar tracking by flowers of an alpine plant

In at least 18 plant families, leaves or flowers can maintain a specific orientation with respect to diurnal movements of the sun. Previous work on heliotropic leaves has demonstrated that blue light (400–500nm) provides the cue for their tracking response. Floral heliotropism occurs in several families of arctic and alpine plants, but the spectral sensitivity of the response has not been studied previously. Moreover, no studies on the spectral sensitivity of any heliotropism have been conducted on wild plants growing in their natural habitat. Working under field conditions, we used coloured acrylic filters to determine whether heliotropism by flowers of the snow buttercup (Ranunculus adoneus) is responsive to broad-band blue or red light. Flowers were able to orient towards the sun under boxes made entirely of blue-transmitting filters and in red-transmitting boxes having a single blue side that faced the sun. In these treatments, solar tracking ability was not significantly different from that observed in adjacent control flowers. In contrast, the precision of solar orientation was significantly reduced in red-transmitting boxes and red boxes with a single blue side oriented away from the sun. In the early morning, flowers covered by red-transmitting boxes failed to orient in the direction of sunrise, suggesting that this floral response, unlike that seen in some heliotropic leaves, lacks a residual‘memory’ for previous solar movements.     

Determinants of seed production in Geranium maculatum

Summary We experimentally examined factors limiting seed production in two populations of the perennial woodland herb Geranium maculatum in central Illinois, USA. To test the pollinator-limitation hypothesis, we compared the seed production of plants whose flowers were supplementarily pollinated with outcross pollen to that of control plants receiving natural pollination only. To test if fruit production by early flowers suppresses fruit and seed formation by late flowers, a third group of plants was prevented from producing seed from the first 50% of the flowers to open (stigmas were excised at flower opening). Finally, to test if seed maturation and flower initiation are correlated with photosynthetic capacity, we performed a defoliation experiment in which either the stem leaves within the inflorescence, the stem leaves below the inflorescence, or the rosette leaves were removed during late flowering. Plants that reccived supplemental pollination produced 1.5–1.6 times more seeds than control plants. We found no difference between hand-pollinated plants and controls in mortality, flowering frequency or number of flowers produced in the year following the experiment. In both control and hand-pollinated plants, the fruit set and total seed production of early flowers were more than twice as high as those of late flowers. In one of the two populations, plants whose early flowers were prevented from setting seed produced significantly more seeds from their late flowers than did control plants. Seed predation was low and did not differ between early and late flowers. Leaf removal did not affect seed number or size in the year of defoliation, nor did it reduce survival or flower production in the subsequent year. This suggests that the plants were able to compensate for a partial defoliation by using stored resources or by increasing photosynthetic rates in the remaining leaves. Taken together, the results demonstrate that both pollinator activity and resource levels influence patterns of seed production in G. maculatum. While seed production was pollinatorlimited in both populations, a seasonal decline in resource availability was apparently responsible for the low seed production by late flowers.     

Optimization and use of a spectrophotometric method for determining polysaccharides in <Emphasis Type="Italic">Echinacea purpurea</Emphasis>

Echinacea purpurea is one of the most widely used immunostimulant plants. Its main active compounds are polysaccharides, glycoproteins, caffeic acid derivatives, alkamides, and melanins. The article describes an optimized extraction procedure that enables spectrophotometric quantification of polysaccharides from Echinacea purpurea. The extraction procedure can be widely applied as it demonstrated to be useful for determining polysaccharide content in flowers and leaves, in summer and autumn plants, in plants with green and red stem, and in plants from two different plantations. A significantly higher content of polysaccharides in flowers in comparison to leaves, as well as in plants with green stems in comparison to plants with red stems was determined. Statistical differences were absent in plants collected in different seasons and growing at different plantations.     

广东省翁源青云山药用植物资源研究

根据实地调查,广东省青云山自然保护区内共记录到野生植物168科605属1266种(含种下分类单位),其中药用植物140科385属586种;所含种类15种及以上的科包括菊科、茜草科、禾本科、唇形科、兰科、蝶形花科等8科。按功效分,活血散瘀类107种、清热解毒类90种、治咳嗽清肺类60种、治疗肠炎类58种、治外伤出血类56种、治毒蛇咬伤类56种、消肿止痛类30种;按药用部位分,全株类304种、根与根茎类185种、叶类131种、茎木类49种、皮类47种、果类42种、花类14种和其他类20种。生活型、生境与海拔相关性分析表明,不同生活型和不同生境与其分布的海拔均差异显著。     

Morphological characterization of extrafloral nectaries and associated ants in tropical vegetation of Los Tuxtlas,Mexico

Extrafloral nectaries (EFNs) are glands that produce sugary exudates and can be located in any vegetative or reproductive structure of the plant. The EFNs occur in different locations on the leaves, stems, inflorescences and flowers (but are not directly involved with pollination). Occurrence of EFNs on plants of coastal vegetation, tropical rain forest and cloud forest in southern Mexico was studied within Los Tuxtlas Biosphere Reserve, Veracruz. We focused on determining the identity and species richness of plants with EFNs, and describing EFNs morphologies. We found 50 species of plants with EFNs (16 families, 31 genera), which corresponds to approximately 5% of the flora reported for the field site (943 species). Trees were the life form with the greatest representation of EFNs while shrubs and epiphytes had the least representation. EFN-bearing plants were particularly well represented in the families Fabaceae, Euphorbiaceae, Convolvulaceae, Bignoniaceae, Malpighiaceae, Passifloraceae, Costaceae, Tiliaceae, while eight other families had only one species. We found six different types of EFNs according to their morphological structure. Dissimilarity analyses between plants and ant species showed that the forest in the Los Tuxtlas region has a rich array of ant species associated with EFNs, with a low niche overlap of ant species. This diversification in ant use of EFNs is of particular interest from an ecological and evolutionary perspective (potential mutualisms with adaptative value), but this deserves still further studies in detail. The present study shall provide basic information for future research in these fields of plant–animal interactions in neotropical vegetation.     

Diet and feeding behavior of Rhinopithecus brelichi at Yangaoping, Guizhou

Expectations of increases in human population growth and accelerated habitat loss, along with the realization that efforts to provide protection for ecosystems that sustain primates have met with limited success, make it critical that conservation plans are grounded firmly in scientific observation. Studies of the diet breadth and feeding behavior of endangered species, therefore, are critical for understanding ecological adaptations and developing a conservation strategy. The diet and feeding ecology of gray snub-nosed monkeys (Rhinopithecus brelichi) were studied in the Fanjingshan National Nature Reserve, Guizhou, China. The monkeys were found to consume 107 different species of trees, shrubs, and ground plants from 58 genera and 28 families. Food items included young leaves, mature leaves, flowers, fruits/seeds, buds, and insects. Among these food items, there were at least 13 evergreen species of tree and liana, 3 species of grasses, and at least 2 kinds of invertebrates collected from decayed wood. Diet varied markedly throughout different seasons. Overall, diet composition (based on feeding records) was 15.3% buds, 25.5% young leaves, 21.8% mature leaves, 9.4% flowers, 21.6% fruits/seeds, and 6.3% other items. The monkeys feed mainly on young leaves and flowers in spring, unripe fruits/seeds and young leaves in summer, ripe fruits/seeds in autumn, and mature leaves and buds in winter. We propose that when inhabiting forests of lower elevation and greater vegetation complexity, R. brelichi is characterized by expanded diet breadth and includes a greater diversity of food types and plant species in its diet. One food type that appears critical to the diet of this species, especially during the winter, are the buds of Magnolia sprengeri. To protect this resource we advocate working with local communities to limit the collection of M. sprengeri, which is used in traditional Chinese medicine and has high economic value for people in the reserve.     

冻伤蓝变对广义虾脊兰属植物中4种吲哚基衍生物含量的影响

以6种广义虾脊兰属植物和2种树兰亚科植物为材料,利用液相色谱 串联三重四极杆质谱仪(LCMS QQQ)测定了冻伤处理前后花和叶片中靛苷、靛红、靛蓝和靛玉红4种吲哚基衍生物的含量,分析广义虾脊兰属植物吲哚基衍生物的生成及种属间含量的差异。结果显示：(1)4种吲哚基衍生物在所测定的6种广义虾脊兰属植物中均被检出,但在2种树兰亚科植物五唇兰和足茎毛兰中均未被发现。(2)在所测定的6种广义虾脊兰属植物花和叶片中,冻伤处理后的靛蓝、靛玉红和靛红含量均显著上升,而靛苷含量显著下降,同时花中的吲哚基衍生物含量均高于叶片。(3)6种广义虾脊兰属植物花和叶中吲哚基衍生物总含量以黄兰花最高,三褶虾脊兰叶最低。研究表明,冻伤处理引起靛苷向靛蓝的大量转化是导致冻伤后广义虾脊兰属植物组织中呈现出蓝色的主要原因,推测吲哚基衍生物可能也是一类与植物防御相关的化合物,在植物抵御逆境中扮演着重要的角色。     

Factors affecting aphid acquisition and transmission of soybean mosaic virus

Myzus persicae transmitted soybean mosaic virus (SMV) most efficiently following 30 or 60 s acquisition probes on infected plants. There were no differences in susceptibility to SMV infection of soybean plants 1 to 12 wk old, but symptoms were more severe in plants inoculated when young than when old. Soybeans inoculated between developmental stages R3 and R6 only showed yellowish-brown blotching on one or more leaves. There were no observable differences in the time of appearance or type of symptoms shown by soybean seedlings inoculated either by sap or by aphids; infected plants became acquisition hosts for aphids 5–6 days after inoculation. There was no change in the efficiency with which M. persicae transmitted SMV from source plants up to 18 wk after inoculation. M. persicae transmitted SMV from leaves of field-grown soybeans when plants were inoculated at developmental stages V6, R2, and R3 and tested as sources 57–74 days after inoculation but not from plants inoculated at R5 and tested as sources 14 to 32 days after inoculation. M. persicae acquired SMV from soybean buds, flowers, green bean pods, and unifoliolate, trifoliolate, and senescent leaves. Middle-aged and deformed leaves were better sources of the virus than buds, unfolding and old symptomless leaves. The results are being incorporated into a computer model of SMV epidemiology.     

The chemical composition of Astragalus. variations within the plants over a 6-year period

COWGILL, U. M. & LANDENBERG, B. D., 1991. The chemical composition of Astragalus : variations within the plants over a 6-year period. No systematic chemical examination has been carried out on seleniferous plants coexisting with non-seleniferous ones. This paper is confined to elemental variation within the plants (12 species of seleniferous Astragalus, 15 species of non-seleniferous Astragalus and seven species of other plants) gathered from 23 sites over a 6-year period in Colorado, Utah and New Mexico, U.S.A. Analytical procedures include X-ray fluorescence and atomic absorption spectrometry. Only 19 elements, of 49 detected, showed significant differences in their quantities in different plant parts. Mn S, Ca, Sr and Mg concentrated in leaves; Al, Si, Ti, Cu, As, F, CI and Br accumulated in stems and K, Rb, Cs, Zn, P and Se were found in quantity in the reproductive parts. A comparison of seleniferous with non-seleniferous species revealed that Mg, S, Mn (leaves), Se, P, K, Zn (flowers/seeds) Cu, F and CI (stems) were more concentrated in seleniferous species ( P < 0.0001) whereas Ca (leaves), Rb (flowers/seeds), As, Al, Si and Br (stems) were present in greater amounts in non-seleniferous ones ( P < 0.0001). An hypothesis is proposed to explain the high amounts of Mg encountered in leaves of these arid region plants; according to the hypothesis some portion of the accumulated Mg functions in arid plants as a humidity stabilizer. Another hypothesis concerns the relationship observed between Se and As. It has been shown that non-seleniferous astragali contained significantly more As than coexisting seleniferous astragali. It is proposed that As may function to time seed production in such a way that non-accumulators have passed the full bloom stage by the time coexisting accumulators were in full bloom and volatilizing quantities of seleniferous compounds.     

Medicinal plants resources of Western Himalayan Palas Valley,Indus Kohistan,Pakistan: Their uses and degrees of risk of extinction

Present study was intended with the aim to document the pre-existence traditional knowledge and ethnomedicinal uses of plant species in the Palas valley. Data were collected during 2015–2016 to explore plants resource, their utilization and documentation of the indigenous knowledge. The current study reported a total of 65 medicinal plant species of 57 genera belonging to 40 families. Among 65 species, the leading parts were leaves (15) followed by fruits (12), stem (6) and berries (1), medicinally significant while, 13 plant species are medicinally important for rhizome, 4 for root, 4 for seed, 4 for bark and 1 each for resin. Similarly, thirteen species were used as a whole while twelve species as partial for medicinal purpose. Further, it is concluded that every part of plants such as bulb, rhizome, roots, barks, leaves, flowers, fruit and seed were used for various ailments. Moreover, among 65 plants species, 09 species are threatened and placed into Endangered (EN) and Least Concern (LC) categories of IUCN. The recorded data are very useful and reflects the significance of the Palas valley as medicinal plants resource area.     

Right-left symmetry of flowers

The flowers of certain plants define a right or left handedness by the sense in which the petals are twisted. Some species and even entire families have flowers of only one particular handedness. There are also plants which produce right-handed as well as left-handed flowers in the same bloom. In the plants of themalvaceae family which belongs to this category, the probability of occurrence of flowers having a given handedness (right or left) undergoes time variations. The possible implications of the right-left symmetry problem of flowers is discussed.     

Protein synthesis in mitochondria purified from roots, leaves and flowers of sugar beet

Highly purified, intact and functional mitochondria were isolated from roots and leaves of a number of fertile and male-sterile lines of sugar beet ( Beta vulgaris L.). Intact and functional mitochondria were successfully isolated from the flowers of fertile plants, but not from the flowers of male-sterile plants. Several alternative methods for the homogenization of male-sterile flowers were tried. Their failure suggests that the mitochondria from male-sterile flowers are more sensitive to mechanical damage than mitochondria from fertile, or other organs of male-sterile, plants.
In organello protein synthesis was optimized with respect to the total concentration of amino acids, the concentration of [³⁵S]-methionine, pH and respiratory substrate. Inhibitor experiments showed that the mitochondrial preparations contained mitochondrial translational activity only. With the exception of one band, no processing or proteolytic breakdown in either root or leaf mitochondrial protein synthesis products could be detected in pulse-chase experiments. Submitochondrial fractionation experiments showed the presence of two soluble polypeptides, whereas all other polypeptides were membrane bound.
The polypeptide patterns of root, leaf and flower mitochondria were very similar with the exception of 4 polypeptides involved in glycine oxidation. These 4 polypeptides were present in large amounts in leaf mitochondria and just detectable in flower mitochondria. The patterns of polypeptides syntesized in mitochondria isolated from roots, leaves and flowers also showed a number of organ-specific differences. Six qualitative and 6 quantitative differences were found between mitochondria isolated from these three organs. No unique polypeptides were found to be synthesized either by flower mitochondria or by mitochondria from roots and leaves of male-sterile plants compared to their male-fertile counterparts.