Nondestructive, Stereological Estimation of Canopy Surface Area

Summary .  We describe a stereological procedure to estimate the total leaf surface area of a plant canopy in vivo, and address the problem of how to predict the variance of the corresponding estimator. The procedure involves three nested systematic uniform random sampling stages: (i) selection of plants from a canopy using the  smooth fractionator , (ii) sampling of leaves from the selected plants using the  fractionator , and (iii) area estimation of the sampled leaves using  point counting . We apply this procedure to estimate the total area of a chrysanthemum ( Chrysanthemum morifolium L. ) canopy and evaluate both the time required and the precision of the estimator. Furthermore, we compare the precision of point counting for three different grid intensities with that of several standard leaf area measurement techniques. Results showed that the precision of the plant leaf area estimator based on point counting is high. Using a grid intensity of 1.76 cm²/point we estimated plant and canopy surface areas with accuracies similar to or better than those obtained using image analysis and a commercial leaf area meter. For canopy surface areas of approximately 1 m² (10 plants), the fractionator leaf approach with sampling fraction equal to 1/9 followed by point counting using a 4.3 cm²/point grid produced a coefficient of error of less than 7%. The  smooth fractionator  can be used to ensure that the additional contribution to the estimator variance due to between-plant variability is small.     

Rapid mass propagation of Chrysanthemum cinerariaefolium Vis. by callus culture and ability to synthesise pyrethrins

 Rapid mass propagation of Chrysanthemum cinerariaefolium from young flower heads was developed to compare the ability of callus, in vitro shoots and rooted plants, and original plants to synthesize pyrethrins. The ability to synthesise all six pyrethrin components increased with differentiation. Jasmolin II and cinerin II were the main products present in mother plant shoots, whereas pyrethrin I was the greater component present in callus and in vitro plants. Clonal propagation increased the pyrethrin I content compared to that of plant shoots and young flowers. Total pyrethrin content was the same in in vitro and plant shoots, but lower in these shoots than in young flowers. The pyrethrin I/pyrethrin II ratio, which is directly related to insecticidal activity, varied from 3.4 in in vitro shoots to 0.87 in mother plant shoots and young flowers. Received: 11 July 1998 / Revision received: 10 March 1999 / Accepted: 12 April 1999     

Chemical Composition,Antioxidant and Anti‐melanogenic Activities of Essential Oils from Chrysanthemum boreale Makino at Different Harvesting Stages

In the present study, the chemical compositions and skin whitening‐related antioxidant and anti‐melanogenic effect of essential oils (EOs) extracted from Chrysanthemum borealeMakino (CBM) (CBMEOs) at vegetative, pre‐flowering and full‐flowering are investigated and contrasted among the three stages. The yields and components of the CBMEOs were different at each stage. The CBMEOs increased DPPH and ABTs scavenging activities and attenuated the α‐melanocyte stimulating hormone (α‐MSH)‐induced tyrosinase activity and melanin synthesis in B16BL6 cells. Among CBMEO components, eugenol had the highest DPPH and ABTs scavenging activities and cuminaldehyde was the strongest inhibitor of α‐MSH‐induced tyrosinase activity and melanin synthesis. The CBMEOs in each stage showed the different levels of phosphorylation of extracellular signal‐regulated kinase1/2 and p38 MAPK. These findings demonstrate that the CBMEOs have antioxidative and anti‐melanogenic activities in all the CBM harvesting stages, resulting in skin‐whitening biological activities and that the levels of their component contents and bioactivities differ among the CBM harvesting stages. The CBMEOs may have the potential for use in cosmetics and alternative medicine.     

Inhibition by polyamines of the hammerhead ribozyme from a Chrysanthemum chlorotic mottle viroid

Background

Viroids are the smallest pathogens known to date. They infect plants and cause considerable economic losses. The members of the Avsunviroidae family are known for their capability to form hammerhead ribozymes (HHR) that catalyze self-cleavage during their rolling circle replication.

Methods

In vitro inhibition assays, based on the self-cleavage kinetics of the hammerhead ribozyme from a Chrysanthemum chlorotic mottle viroid (CChMVd-HHR) were performed in the presence of various putative inhibitors.

Results

Aminated compounds appear to be inhibitors of the self-cleavage activity of the CChMVd HHR. Surprisingly the spermine, a known activator of the autocatalytic activity of another hammerhead ribozyme in the presence or absence of divalent cations, is a potent inhibitor of the CChMVd-HHR with K_i of 17 ± 5 μM. Ruthenium hexamine and TMPyP4 are also efficient inhibitors with K_i of 32 ± 5 μM and IC₅₀ of 177 ± 5 nM, respectively.

Conclusions

This study shows that polyamines are inhibitors of the CChMVd-HHR self-cleavage activity, with an efficiency that increases with the number of their amino groups.

General significance

This fundamental investigation is of interest in understanding the catalytic activity of HHR as it is now known that HHR are present in the three domains of life including in the human genome. In addition these results emphasize again the remarkable plasticity and adaptability of ribozymes, a property which might have played a role in the early developments of life and must be also of significance nowadays for the multiple functions played by non-coding RNAs.     

Molecular evidence for multiple polyploidization and lineage recombination in the Chrysanthemum indicum polyploid complex (Asteraceae)

The Chrysanthemum indicum polyploid complex comprises morphologically differentiated diploids, tetraploids and hybrids between C. indicum and C. lavandulifolium. The relationships between species and cytotypes within this complex remain poorly understood. Random amplified polymorphic DNAs (RAPDs), intersimple sequence repeats (ISSRs) and chloroplast SSR markers were used to elucidate the genetic diversity and relationships of the C. indicum polyploid complex. Molecular analysis of three diploid and nine tetraploid populations provided strong evidence for recurrent origins and lineage recombination in the C. indicum polyploid complex. The high similarity in molecular marker profiles and cpDNA haplotypes between the diploids and tetraploids distributed in the Shen-Nong-Jia Mountain area of China suggested an autopolyploid origin of the tetraploids, while the tetraploids from other populations may have originated via allopolyploidization. Lineage recombination was revealed by the extensive sharing of chloroplast haplotypes and genetic markers among the tetraploid populations with different origins. Multiple differentiation and hybridization/polyploidization cycles have led to an evolutionary reticulation in the C. indicum polyploid complex, and resulted in the difficulties in systematic classification.     

甘菊木质素调控转录因子ClSND1-like的克隆与表达分析

为了探索纤维特异表达的NAC类转录因子SND1(secondary wall-associated NAC domain protein1,SND1)在甘菊(Chrysanthemum lavandulifolium)生长发育及非生物胁迫中的作用,该研究从甘菊中克隆了ClSND1-like基因,并对其进行生物信息学、亚细胞定位及表达模式分析。结果发现:(1)ClSND1-like基因的编码区全长1185 bp,共计编码394个氨基酸,是一个不稳定的亲水性蛋白,与除虫菊基因亲缘关系较近。(2)亚细胞定位结果表明,ClSND1-like基因在叶中不表达,在茎的导管壁上特异表达,属于木质素特异表达基因。(3)实时荧光定量PCR结果发现,ClSND1-like基因在茎中表达量最高,在根和叶中表达量极低,且随着茎秆的老化,表达量逐渐升高;在渗透胁迫和盐胁迫中表达量均显著提高。研究推测,ClSND1-like基因与甘菊木质素形成相关,并参与调控植物生长及盐和渗透胁迫。该结果为ClSND1-like基因在甘菊生长和非生物胁迫抗性中的研究奠定了基础,也为菊属植物的生长及抗性研究提供了新思路。     

The Synthesis of (3H)-Gibberellin A9 with High Specific Activity

The synthesis of 2,3-(³H)-gibberellin A₉ (GA₉) with a specific activity of 47 Ci mmole^?1 is described. △^2,3GA₉ methyl ester epoxide was converted to (³H)-GA₉ methyl ester epoxide using carrier-free tritium gas. This product was de-epoxidized then hydrolysed to yield (³H)-GA₉.     

Quantitative short-day photoperiodic response in larval development and its adaptive significance in an adult-overwintering cerambycid beetle, Phytoecia rufiventris

The chrysanthemum longicorn beetle, Phytoecia rufiventris, overwinters in the adult stage and reproduces in spring. Larvae of this beetle develop during summer inside a host stem or root. In the present study, photoperiodic control of larval development and its adaptive significance were examined in this beetle using an artificial diet. Larvae showed a short-day photoperiodic response at 25 °C with a critical day length of around 14 h; larvae reared under short-day conditions pupated, whereas those reared under long-day conditions entered summer diapause with some supernumerary molts and did not pupate. A similar response was found at 30 °C, but with a shorter critical day length. Below the critical day length, a shorter day length corresponded to a shorter larval period. Larvae transferred from long-day conditions to various photoperiods showed a similar quantitative response. Field rearing of larvae starting at various times of year showed that pupation occurs within a relatively short period in early autumn. Field rearing of pupae and adults at various times indicated that only pupation in early autumn results in a high survival rate until winter. Earlier or later pupation led to a low survival rate due to death before overwintering in the adult and pupal stages, respectively. Thus, in P. rufiventris, timing of pupation regulated by the quantitative short-day photoperiodic response is vital for survival. Relatively lower developmental threshold in the pupal stage supports this hypothesis.     

不同R∶FR值对菊花叶片气孔特征和气孔导度的影响

以切花菊品种"神马(Jinba)"为试材,2010年10月至2011年2月间在南京信息工程大学试验温室采用不同Red (660±10) nm: Far-red (730±10) nm值的LED光源短日处理,研究了温室切花菊叶片气孔特征和气孔导度对不同R∶FR值的响应。结果表明:不同R∶FR值短日处理35d菊花叶片的上表皮和下表皮的气孔直径分别以R∶FR值4.5和6.5处理最大,均以R∶FR值2.5处理最小,气孔密度和气孔开度均以R∶FR=2.5处理最高,以R∶FR值6.5处理最低,下表皮的气孔密度、气孔开度明显高于上表皮;不同R∶FR值处理叶片的气孔开张比和气孔指数差异不显著;在相同光强下,菊花叶片气孔导度和光合速率由大到小的R∶FR值顺序依次为2.5、4.5、0.5、6.5。叶片气孔导度与气孔指数、气孔密度、气孔开张比和气孔开度成正相关,与气孔长度和气孔宽度呈负相关;R∶FR值在2.5-6.5范围内,随光质中红光成分增加,叶片气孔密度、气孔指数、气孔开度、气孔开张比和气孔导度显著降低。