声波刺激对菊花愈伤组织膜脂物理状态和膜脂代谢的影响

以蔗糖梯度法纯化的菊花(Dendranthema morifolium (Ramat.) Tzvel.)愈伤组织质膜微囊为材料,研究了声波刺激下质膜膜脂代谢和物理状态的变化.结果表明, 一定强度(100 dB)和频率(1 000 Hz)的声波刺激使质膜磷酸二脂含量和二苯己三烯(DPH)荧光偏振值降低,质膜光散射值、MC540荧光强度和磷酸单脂含量增加.表明一定强度和频率的声波刺激使质膜变疏松,膜的流动性增加,膜表面电荷密度和疏水性降低,膜脂合成代谢增加,分解代谢减弱.由此可见,膜脂物理状态和膜脂代谢对声波刺激极为敏感.     

Experience-induced preference for oviposition repellents derived from a non-host plant by a specialist herbivore

Foraging adults of phytophagous insects are attracted by host‐plant volatiles and supposedly repelled by volatiles from non‐host plants. In behavioural control of pest insects, chemicals derived from non‐host plants applied to crops are expected to repel searching adults and thereby reduce egg laying. How experience by searching adults of non‐host volatiles affects their subsequent searching and oviposition behaviour has been rarely tested. In laboratory experiments, we examined the effect of experience of a non‐host‐plant extract on the oviposition behaviour of the diamondback moth (DBM), Plutella xylostella, a specialist herbivore of cruciferous plants. Naive ovipositing DBM females were repelled by an extract of dried leaves of Chrysanthemum morifolium, a non‐host plant of DBM, but experienced females were not repelled. Instead they were attracted by host plants treated with the non‐host‐plant extract and laid a higher proportion of eggs on treated than on untreated host plants. Such behavioural changes induced by experience could lead to host‐plant range expansion in phytophagous insects and play an important role in determining outcome for pest management of some behavioural manipulation methods.     

Suppressed Leaf Senescence in Chrysanthemum Transformed with a Mutated Ethylene Receptor GenemDG-ERS1(etr1-4)

Previously, Narumi et al. (2005) generated chrysanthemum plants transformed with a mutated ethylene receptor gene (mDG-ERS1(etr1-4<), and showed that thein vitro plantlets of the transformants grown aseptically in a small plastic container had a reduced sensitivity to ethylene resulting in reduced leaf yellowing after exposure to exogenous ethylene. In the present study we evaluated ethylene sensitivity of the transformants using soil-grown mature plants. When the shoots detached from soil-grown plants were treated with exogenous ethylene under continuous light, leaf yellowing (senescence) was delayed in the transformants as compared with the non-transformed plants. Furthermore, when the detached shoots were kept in darkness without ethylene treatment, the transformants showed reduced senescence as compared with those of the non-transformed plants. These results demonstrated that the mutated ethylene receptor genemDG-ERS1(etr1-4) could confer reduced sensitivity to ethylene in the leaves of mature chrysanthemum plants. This gene may be useful to generate transgenicCompositae vegetables with leaves green for a longer time and thus having a longer shelf life.     

Simulation of leaf area development based on dry matter partitioning and specific leaf area for cut chrysanthemum

This work aims to predict time courses of leaf area index (LAI) based on dry matter partitioning into the leaves and on specific leaf area of newly formed leaf biomass (SLA(n)) for year-round cut chrysanthemum crops. In five glasshouse experiments, each consisting of several plant densities and planted throughout the year, periodic destructive measurements were conducted to develop empirical models for partitioning and for SLA(n). Dry matter partitioning into leaves, calculated as incremental leaf dry mass divided by incremental shoot dry mass between two destructive harvests, could be described accurately (R(2 )= 0.93) by a Gompertz function of relative time, R(t). R(t) is 0 at planting date, 1 at the start of short-days, and 2 at final harvest. SLA(n), calculated as the slope of a linear regression between periodic measurements of leaf dry mass (LDM) and LAI, showed a significant linear increase with the inverse of the daily incident photosynthetically active radiation (incident PAR, MJ m(-2 )d(-1)), averaged over the whole growing period, the average glasshouse temperature and plant density (R(2 )= 0.74). The models were validated by two independent experiments and with data from three commercial growers, each with four planting dates. Measured shoot dry mass increase, initial LAI and LDM, plant density, daily temperature and incident PAR were input into the model. Dynamics of LDM and LAI were predicted accurately by the model, although in the last part of the cultivation LAI was often overestimated. The slope of the linear regression of simulated against measured LDM varied between 0.95 and 1.09. For LAI this slope varied between 1.01 and 1.12. The models presented in this study are important for the development of a photosynthesis-driven crop growth model for cut chrysanthemum crops.     

杭白菊的化学成分研究：两个新三萜酯的结构测定

从杭白菊(Dendranthema morifolium (Ramat. )Tzvel.)的乙醚部分分离出13个化合物。运用波谱技术和化学方法证明其中2个为新化合物,命名为棕榈酸16β,22α-二羟基假蒲公英甾醇酯(1)和棕榈酸16β,28-二羟基羽扇醇酯(2)。     

Rates of cell division in the young prefloral shoot apex ofChrysanthemum segetum L.

Summary The rate of cell division was determined by the colchicine induced metaphase-accumulation technique in the young prefloral shoot apex of the quantitative long-day plantChrysanthemum segetum L. growing under conditions favourable to flowering (16-hour photoperiod; 124Em^–2s^–1; 22 °C). Cell cycle duration was evaluated in relation to the location of the cells in the intact apex. The cell cycle durations were 53.5 hours, 47.4 hours, and 97.7 hours in the axial, lateral and subapical central cells respectively. Compared with previous results, these data give evidence of the major role played by the early increase in cell division rate of axial cells in the new pattern of the prefloral shoot apex at its initial stage of development. By comparison with the vegetative shoot apex, the cell cycle duration was preferentially shortened in the axial zone; it was only slightly altered in the lateral zone while it was lengthened in the vacuolating subapical central cells. In the three zones within the prefloral shoot apex, the duration of mitosis was constant (3.2 to 3.3 hours) and the same as in the vegetative shoot apex.     

Wild chrysanthemum extract prevents UVB radiation-induced acute cell death and photoaging

Wild chrysanthemum (Chrysanthemum indicum L.) is traditionally used in folk medicine as an anti-inflammatory agent. It is also used in the southwest plateau region of China to prevent ultraviolet-induced skin damage. However, the role and mechanism by which wild chrysanthemum prevents UV-induced skin damage and photoaging have never been investigated in vitro. In the present study, we found that aqueous extracts from wild chrysanthemum strongly reduced high-dose UVB-induced acute cell death of human immortalized keratinocytic HaCat cells. Wild chrysanthemum extract was also demonstrated to reduce low-dose UVB-induced expression of the photoaging-related matrix metalloproteinases MMP-2 and MMP-9. The ROS level elevated by UVB irradiation was strongly attenuated by wild chrysanthemum extract. Further study revealed that wild chrysanthemum extract reduced UVB-triggered ERK1/2 and p38 MAPK phosphorylation and their protective role, which is partially dependent on inhibiting p38 activation. These results suggest that wild chrysanthemum extract can protect the skin from UVB-induced acute skin damage and photoaging by reducing the intracellular reactive oxygen species (ROS) level and inhibiting p38 MAPK phosphorylation. The present study confirmed the protective role of wild chrysanthemum against UV-induced skin disorders in vitro and indicated the possible mechanism. Further study to identify the active components in wild chrysanthemum extract would be useful for developing new drugs for preventing and treating skin diseases, including skin cancer and photoaging, induced by UV irradiation.     

Induced Resistance to Meloidogyne hapla by other Meloidogyne species on Tomato and Pyrethrum Plants

Advance inoculation of the tomato cv. Celebrity or the pyrethrum clone 223 with host-incompatible Meloidogyne incognita or M. javanica elicited induced resistance to host-compatible M. hapla in pot and field experiments. Induced resistance increased with the length of the time between inoculations and with the population density of the induction inoculum. Optimum interval before challenge inoculation, or population density of inoculum for inducing resistance, was 10 days, or 5,000 infective nematodes per 500-cm³ pot. The induced resistance suppressed population increase of M. hapla by 84% on potted tomato, 72% on potted pyrethrum, and 55% on field-grown pyrethrum seedlings, relative to unprotected treatments. Pyrethrum seedlings inoculated with M. javanica 10 days before infection with M. hapla were not stunted, whereas those that did not receive the advance inoculum were stunted 33% in pots and 36% in field plots. The results indicated that advance infection of plants with incompatible or mildly virulent nematode species induced resistance to normally compatible nematodes and that the induced resistance response may have potential as a biological control method for plant nematodes.     

Flavonoid distribution patterns in Leucanthemum and related species from North Africa

Flavonoid data is reported for 16 species including eight species of Leucanthemum from North Africa, four from Europe and related species in the Chrysanthemum-Leucanthemum complex. Flavonols, especially quercetin, isorhaamnetin, kaempferol, patuletin and spinacetin, are predominant in the North African species. Flavones, which are common in Leucanthemum species in Europe, are of very rare occurrence in the North African species. The relationship of the species based on the distribution of flavonoid glycosides and aglycones from the ray florets is discussed.     

Interactions of daminozide, 2, 2′-dipyridyl,and gibberellins A3, A9 and A20, in stem extension inChrysanthemum morifolium Ramat: an indication that daminozide may not inhibit the responses to GA9 or GA20 by blocking gibberellin hydroxylation

Interactions between the growth retardant daminozide (a substituted succinamic acid) and a subsequent application (1 or 10 g) of either gibberellin A₃, A₉ or A₂₀, on stem extension inChrysanthemum morifolium cv. Bright Golden Anne, indicated that pre-treatment of plants with daminozide largely prevented the response to GA₂₀ as well as to GA₉. The daminozide-GA₃ interaction on total stem length was dependent upon the dose of GA₃ such that, by flowering time, 1 g of GA₃ had virtually eliminated the retardant effect, while 10 g of GA₃ increased stem length to a value similar to that achieved by control shoots receiving 10 g of GA₃. In contrast, prior application of 2, 2-dipyridyl (an inhibitor of hydroxylation in some plant and animal systems) had no significant influence on the time courses of response to any of the GAs. In the absence of daminozide (and 2, 2-dipyridyl) all three GAs were very active in promoting internode extension soon after their application. If 2, 2-dipyridyl can block hydroxylation reactions in chrysanthemum tissues, the results do not support the hypothesis that daminozide restricts GA₉- (or GA₂₀-) induced stem elongation by preventing the hydroxylation of GA₉.