CRISPR/Cas技术在抗除草剂作物育种中的研究与应用进展

CRISPR/Cas系统是一种简单、低成本、高效、精准的基因编辑技术,该技术能够进行基因的定向改造,加速新品种培育进程,在种质资源创制中的应用潜力较高。概述了CRISPR/Cas系统的技术原理及其在作物抗除草剂育种中的应用,简要指出了目前CRISPR/Cas技术在抗除草剂种质创制及应用过程中存在的问题及发展方向,以期为今后利用CRISPR/Cas技术创制抗除草剂新种质提供理论依据。     

东北地区6所高校校园种子植物属级相似性分析

校园植物能反映校园植物多样性水平。为了研究东北地区高校校园种子植物属组成的相似性,本研究以沈阳农业大学等6所位于东北地区的高校中的校园种子植物为研究对象,并选取北方极为常见的两个科：菊科（Asteraceae）和蔷薇科（Rosaceae）,研究其属组成的差异性与相似性。结果表明,6所高校校园种子植物属间相似性较高。菊科属的组成在各高校间差异性显著,蔷薇科属的组成在各高校相似性高。校园植物种类的多样性与差异性与校园面积、校园所处位置相关。本研究旨在为东北乃至其他地区高校校园生物多样性的进一步研究和其他高校校园植物调查提供基础。     

Hunting and Plant Community Dynamics in Tropical Forests: A Synthesis and Future Directions

This synthesis builds on the preceding articles of this Special Section and has three goals. We first review the nascent literature that addresses indirect effects of hunting for tropical forest plant communities. Next, we highlight the potential indirect effects of hunting for other groups of organisms. Our final goal is to consider what could be done to ameliorate the demographic threats to harvest-sensitive game species caused by unsustainable hunting. Three conclusions are possible at this time concerning the impact of hunting for tropical forest plant communities: (1) Hunting tends to reduce seed movement for animal-dispersed species with very large diaspores; (2) Hunting reduces seed predation by granivorous vertebrates for species with large seeds; and (3) Hunting alters the species composition of the seedling and sapling layers. The cascading effects of hunting are already known to affect bruchid beetles and dung beetles and are likely to affect other, nongame taxa. To ameliorate these problems, several lines of research should be further explored to facilitate the development of game management plans including: (1) alternative use of sources of animal protein; (2) income supplementation for local people from sources other than wild meat; (3) outreach and extension activities for communities; (4) recognition and facilitation of the shifting of attitudes towards hunting; (5) implementation of community-based wildlife management programs in regulated-use areas such as extractive reserves; and (6) landscape-scale conservation planning that maximizes the source-sink dynamics of harvested and unharvested game populations and enforces game regulations in strictly protected areas.     

Doctrine of Signatures: An explanation of medicinal plant discovery or Dissemination of knowledge?

The Doctrine of Signatures (DOS) is found throughout the world. Most scholars dismiss it as a “primitive” or “prescientific” idea. Despite its long history, the doctrine has had little critical review. A careful evaluation of signatures suggests four things. (1) There is no evidence that morphological plant signatures ever led to the discovery of medicinal properties. Considering DOS in this manner is unproductive and largely untestable. (2) Signatures are post hoc attributions rather than a priori clues to the utility of medicinal plants. (3) It is productive to redefine signatures to include organoleptic properties associated with therapeutic value. Plants with strong odors or bitter tastes, for example, commonly are found in pharmacopoeias. (4) DOS should be considered for what it primarily is—a way of disseminating information. DOS fundamentally is a mnemonic and, therefore, is exceedingly valuable in traditional cultures.     

An experimental test of the effects of resources and sex ratio on maternal fitness and phenotypic selection in gynodioecious Fragaria virginiana

Resources, sex ratio, and seed production by hermaphrodites covary among natural populations of many gynodioecious plant species, such that they are functionally "more dioecious" as resources become more limiting. Strong correlations among these three factors confound our understanding of their relative roles in maintaining polymorphic sexual systems. We manipulated resource availability and sex ratio and measured their effects on relative fertility and phenotypic selection through the maternal fitness of females and hermaphrodites of Fragaria virginiana. Two results were particularly surprising. First, hermaphrodites showed little variability in fecundity across resource treatments and showed strong positive and context-dependent selection for fruit set. This suggests that variation in hermaphrodite seed production along resource gradients in nature may result from adaptation rather than plasticity. Second, although females increased their fecundity with higher resources, their fertility was unaffected by sex ratio, which is predicted to mediate pollen limitation of females in natural populations where they are common. Selection on petal size of females was also weak, indicating a minimal effect of pollinator attraction on variation in the fertility of female plants. Hence, we found no mechanistic explanation for the complete absence of high-resource high female populations in nature. Despite strong selection for increased fruit set of hermaphrodites, both the strength of selection and its contribution to the maintenance of gynodioecy are severely reduced under conditions where females have high relative fecundity (i.e., low resources and high-female sex ratios). High relative fertility plus high female frequency means that the evolution of phenotypic traits in hermaphrodites (i.e., response to selection via seed function) should be manifested through females because most hermaphrodites will have female mothers. Fruit set was never under strong selection in females; hence, selection to increase fruit set hermaphrodites will be less effective in maintaining their fruiting ability in natural populations with low resources and high female frequency. In sum, both sex ratio and resource availability influence trait evolution indirectly-through their effects on relative fertility of the sexes and patterns of selection. Sex ratio did not impose strong pollen limitation on females but did directly moderate the outcome of natural selection by biasing the maternal sex of the next generation. This direct effect of sex ratio on the manifestation of natural selection is expected to have far greater impact on the evolution of traits, such as seed-producing ability in hermaphrodites and the maintenance of sexual polymorphisms in nature, compared to indirect effects of sex ratio on relative fertility of the sexes.     

Bioactivity of phytochemicals in some lesser-known plants and their effects and potential applications in livestock and aquaculture production systems

Livestock and aquaculture production is under political and social pressure, especially in the European Union (EU), to decrease pollution and environmental damage arising due to animal agriculture. The EU has banned the use of antibiotics and other chemicals, which have been shown to be effective in promoting growth and reducing environment pollutants because of the risk caused to humans by chemical residues in food and by antibiotic resistance being passed on to human pathogens. As a result of this, scientists have intensified efforts in exploiting plants, plant extracts or natural plant compounds as potential natural alternatives for enhancing the livestock productivity. This paper discusses work on the effects of various phytochemicals and plant secondary metabolites in ruminant and fish species. The focus is on (i) plants such as Ananas comosus (pine apple), Momordica charantia (bitter gourd) and Azadirachta indica (neem) containing anthelmintic compounds and for their use for controlling internal parasites; (ii) plants containing polyphenols and their applications for protecting proteins from degradation in the rumen, increasing efficiency of microbial protein synthesis in rumen and decreasing methane emission; for using as antioxidants, antibacterial and antihelmintic agents; and for changing meat colour and for increasing n-3 fatty acids and conjugated linoleic acid in meat; (iii) saponin-rich plants such as quillaja, yucca and Sapindus saponaria for increasing the efficiency of rumen fermentation, decreasing methane emission and enhancing growth; for producing desired nutritional attributes such as lowering of cholesterol in monogastric animals; for increasing growth of fish (common carp and Nile tilapia) and for changing male to female ratio in tilapia; and for use as molluscicidal agents; (iv) Moringa oleifera leaves as a source of plant growth factor(s), antioxidants, beta-carotene, vitamin C, and various glucosinolates and their degraded products for possible use as antibacterial, antioxidant, anticarcinogenic and antipest agents; (v) Jatropha curcas toxic variety with high levels of various phytochemicals such as trypsin inhibitor, lectin, phytate and phorbol esters in seeds limiting the use of seed meal in fish and livestock diets; and the use of phorbol esters as bio-pesticidal agent; and (vi) lesser-known legumes such as Entada phaseoloides seeds containing high levels of trypsin inhibitor and saponins, Sesbania aculeate seeds rich in non-starch polysaccharides and Mucuna pruriens var. utilis seeds rich in l-3,4-dihydroxyphenylalanine and their potential as fish feed; Cassia fistula seeds as a source of antioxidants; and the use of Canavalia ensiformis, C. gladiata and C. virosa seeds containing high levels of trypsin inhinitor, lectins and canavanine. The paper also presents some challenges and future areas of work in this field.     

PCR primers for polymorphic microsatellite loci in the plant‐ant Azteca ulei cordiae (Formicidae: Dolichoderinae)

Twelve microsatellite loci were isolated from the Peruvian tropical plant‐ant, Azteca ulei cordiae (Hymenoptera: Dolichoderinae). High levels of within‐population variation were observed at most loci, with number of alleles ranging from four to 18, and heterozygosity from 0.118 to 1 per population sample. Cross‐species amplification of these loci was also successfully tested in several other species of the same ant genus Azteca.     

Biodiversity and water quality variations in constructed wetland of Yongding River system

This research was carried on in constructed wetlands of Guan-Ting Reservoir, Beijing, China, from 2004 to 2005. The phytoplankon community was composed of 8 divisions (94 species, including genus and varieties) and the average cell density was 980.93× 10⁴ cells per liter. The dominant divisions were Chlorophyta (36.8%), Bacillariophyta (31.0%) and Cyanophyta (23.4%). The removal rate of phytoplankton density was 72.7%. There was a positive linear correlation between phytoplankon density and total phosphorus. Here, 7 families (13 species) of aquatic vasular plants were found, which constituted emerging and submerging macrophyte communities. In the wetland system, the zooplankton community consisted of Protozoa, Rotifera, Cladocera and Copepoda (70 species). The average density was 4883 individuals per liter. Protozoan and Rotifera were the dominant groups and the removal rate of their density was 81.9%. The correlation between zooplankton and phytoplankton presented a quadratic curve. Also, the zoobenthos community contained Olisochaeta, Uniramia, Crustacea and Mollusca (15 species). The average density was 5670 individuals per m² (62.3% was Uniramia) and the removal rate of their density was 92.4 %. The wetland system reduced COD_Mn, BOD₅, TN, NH_3-N, NO_3-N, TP (total phosphor), PO_4-P and SS in the water of Yong Ding River at 52.9%–99.1%.     

Classification of life cycle form spectrum of artificial community of Pinus svlvestris var. mongolica

The plant life cycle form and its spectrum features of different plants in the artificial community of Pinus svlvestris var. mongolica at the botanical garden of Northeast Forestry University were classified by PCA method. For canopy layer plants, the vegetative growth (V) accounted for 46%, the sexual growth (S) accounted for 35%, and the clonal growth (C) accounted for the rest 19%. For succession layer plants, V accounted for more than 50%, and C accounted for a little higher than S did. For herbaceous layer plants, V accounted for nearly 47%, which was only 4% higher than that of S, and C only accounted for 11%. These findings indicate that the plant life cycle forms of canopy layer plants and herbaceous layer plants were VS transition form with V form as the main form, while the succession layer plants were V form. At the viewpoint of artificial community, the life cycle form can be described as V_0.49S_0.33C_0.18, a typical VS transition form, indicating that most of the species studied in this community are in a healthy status with the V form. Moreover, the relatively high (33%) percentage in the S form indicates that the community also tends to sexual growth for offspring, although it will be steady within a period of time for the vegetative growth of bodies.     

High-frequency shoot multiplication in Artemisia vulgaris L. using thidiazuron

An in vitro propagation system for Artemisia vulgaris L., a traditional medicinal plant, has been developed. The best organogenic response, including adventitious shoot number and elongation, was obtained when hypocotyl segments were cultured onto MS medium supplemented with 4.54 μM TDZ (N-phenyl-N′-(1,2,3-thidiazol-yl) urea). Up to 28 shoots formed per explant for an optimal duration of exposure of 48 days. Regenerated shoots formed roots when subcultured onto a medium containing 8.56 μM IAA (indole-3-acetic acid). Healthy plantlets were transferred to a garden soil:farmyard soil:sand (2:1:1) mixture for acclimatization, which was successful, and subsequent maturity was achieved under greenhouse conditions over a six-month period. The survival rate of the plantlets varied under acclimatization. The regeneration protocol developed in this study provides a basis for germplasm conservation and for further investigation of medicinally active constituents of A. vulgaris. This optimized protocol has been successfully employed for genetic transformation studies in A. vulgaris, which are currently underway in our laboratory.