Ratoon rice generated from primed parent plants exhibit enhanced herbivore resistance.

Rice ratooning is practiced in many rice-growing countries for achieving increased rice production with limited labour input. Here, we report that attack by insect herbivores, or treatment with a defense signaling compound in parent plants, can prime anti-herbivore defense responses in subsequent ratoon plants. We compared the defense responses of rice ratoons generated from parent plants that had been either infested by Cnaphalocrocis medinalis (rice leaffolder, LF) caterpillars or treated with methyl jasmonate (MeJA) during vegetative growth, with ratoons generated from control parent plants. Ratoon plants generated from parents receiving prior LF infestation or MeJA treatment exhibited higher jasmonic acid (JA) levels, as well as elevated levels of transcripts of defense-related genes associated with JA signaling. In addition, elevated activities of peroxidase, polyphenol oxidase and trypsin protease inhibitor were observed, as well as enhanced resistance towards subsequent LF infestation. Pre-priming of ratoon defense responses was significantly reduced in plants where expression of OsAOS (allene oxide synthase, involved in JA biosynthesis) or OsCOI1 (CORONATINE INSENSITIVE1, involved in JA perception) was inhibited by RNA interference. Our results indicate that herbivore exposure or MeJA treatment in rice parent plants enhances anti-herbivore resistance in subsequently generated ratoons through priming of JA-mediated defenses.

Determination of arsenic species in Solanum Lyratum Thunb using capillary electrophoresis with inductively coupled plasma mass spectrometry.

A simple and highly efficient interface to couple capillary electrophoresis with inductively coupled plasma mass spectrometry by a microflow polyfluoroalkoxy nebulizer and a quadruple ion deflector was developed in this study. By using this interface, six arsenic species, including arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, and arsenocholine, were baseline-separated and determined in a single run within 11 min under the optimized separation conditions. The instrumental detection limit was in the range of 0.02-0.06 ng/mL for the six arsenic compounds. Repeatability expressed as the relative standard deviation (n = 5) of both migration time and peak area were better than 2.5 and 4.3% for six arsenic compounds. The proposed method, combined with a closed-vessel microwave-assisted extraction procedure, was successfully applied for the determination of arsenic species in the Solanum Lyratum Thunb samples from Anhui province in China with the relative standard deviations (n = 5) ≤4%, method detection limits of 0.2-0.6 ng As/g and a recovery of 98-104%. The experimental results showed that arsenobetaine was the main speciation of arsenic in the Solanum Lyratum Thunb samples from different provinces in China, with a concentration of 0.42-1.30 µg/g.

Stress signaling in response to polycyclic aromatic hydrocarbon exposure in Arabidopsis thaliana involves a nucleoside diphosphate kinase, NDPK-3.

MAIN CONCLUSION: The study is the first to reveal the proteomic response in plants to a single PAH stress, and indicates that NDPK3 is a positive regulator in the Arabidopsis response to phenanthrene stress. Polycyclic aromatic hydrocarbons (PAHs) are highly carcinogenic pollutants that are byproducts of carbon-based fuel combustion, and tend to persist in the environment for long periods of time. PAHs elicit complex, damaging responses in plants, and prior research at the physiological, biochemical, and transcriptional levels has indicated that reactive oxygen species (ROS) and oxidative stress play major roles in the PAH response. However, the proteomic response has remained largely unexplored. This study hypothesized that the proteomic response in Arabidopsis thaliana to phenanthrene, a model PAH, would include a strong oxidative stress signature, and would provide leads to potential signaling molecules involved. To explore that proteomic signature, we performed 2D-PAGE experiments and identified 30 proteins levels that were significantly altered including catalases (CAT), ascorbate peroxidase (APX), peroxiredoxins (POD), glutathione-S-transferase, and glutathione reductase. Also upregulated was nucleoside diphosphate kinase 3 (NDPK-3), a protein known to have metabolic and stress signaling functions. To address whether NDPK-3 functions upstream of the oxidative stress response, we measured levels of stress-responsive enzymes in NDPK-3 overexpressor, loss-of-function knockout, and wild-type plant lines. In the NDPK-3 overexpressor, the enzyme activities of APX, CAT, POD, as well as superoxide dismutase were all increased compared to wild type; in the NDPK-3 knockout line, these enzymes had reduced activity. This pattern occurred in untreated as well as phenanthrene-treated plants. These data support a model in which NDPK-3 is a positive regulator of the Arabidopsis stress response to PAHs.

Transcriptome-wide identification of the genes responding to replanting disease in Rehmannia glutinosa L. roots.

The development of the medicinal plant Rehmannia glutinosa L. are severely declined when are replanted on the soil of the preceding crops being themselves. The biological basis of this so called "replanting disease" is unknown. Here, we have exploited the parallel sequencing capacity of both RNA-seq and DGE technology to ascertain what genes are responsive to the replanting disease in roots of R. glutinosa. RNA-seq analysis generated 99,708 non-redundant consensus sequences from the roots of the first year (R1) and the second year (R2) replanted R. glutinosa plants. From this set, a total of 48,616 transcripts containing a complete or partial encoding region was identified. Based on this resource, two DGE tag libraries were established to capture the transcriptome differences between the R1 and R2 libraries. Finally, a set of 2,817 (1,676 up- and 1,141 down-regulated) differentially transcribed genes was screened, and 114 most strongly differentially transcribed genes were identified by DGE analysis between first year and replanted plants. Furthermore, a more detailed examination of 16 selected candidates was carried out by qRT-PCR. The indication was that replanting could promote Ca(2+) signal transduction and ethylene synthesis, resulting in forming of the replanting disease. We analyzed the biomass indexes of replanted R. glutinosa roots by irrigating Ca(2+) signal blockers. The results suggested that the alleviation of the disease impairment could be the decrease of Ca(2+) signal transduction. This study provided a global survey of the root transcriptome in replanted R. glutinosa roots at the tuberous root expansion stage. As a result, a number of candidate genes underlying the replanting disease have been identified.

Effect of arsenite-oxidizing bacterium B. laterosporus on arsenite toxicity and arsenic translocation in rice seedlings.

Arsenite [As (III)] oxidation can be accelerated by bacterial catalysis, but the effects of the accelerated oxidation on arsenic toxicity and translocation in rice plants are poorly understood. Herein we investigated how an arsenite-oxidizing bacterium, namely Brevibacillus laterosporus, influences As (III) toxicity and translocation in rice plants. Rice seedlings of four cultivars, namely Guangyou Ming 118 (GM), Teyou Hang II (TH), Shanyou 63 (SY) and Minghui 63 (MH), inoculated with or without the bacterium were grown hydroponically with As (III) to investigate its effects on arsenic toxicity and translocation in the plants. Percentages of As (III) oxidation in the solutions with the bacterium (100%) were all significantly higher than those without (30-72%). The addition of the bacterium significantly decreased As (III) concentrations in SY root, GM root and shoot, while increased the As (III) concentrations in the shoot of SY, MH and TH and in the root of MH. Furthermore, the As (III) concentrations in the root and shoot of SY were both the lowest among the treatments with the bacterium. On the other hand, its addition significantly alleviated the As (III) toxicity on four rice cultivars. Among the treatments amended with B. laterosporus, the bacterium showed the best remediation on SY seedlings, with respect to the subdued As (III) toxicity and decreased As (III) concentration in its roots. These results indicated that As (III) oxidation accelerated by B. laterosporus could be an effective method to alleviate As (III) toxicity on rice seedlings.

Research status and prospect of ratoon rice in China under mechanically harvested condition.

The proportion and area of ratoon rice planting in China have been substantially increased, due to continuous improvement of rice breeding methods and consecutive innovation of cultivation technology, which has developed into one of rice planting modes with significant production efficiency. Combining the experience in research and practice, from the perspective of crop physiology and ecology, we reviewed the current situation and prospects of high-yielding formation and physiological mechanisms of ratoon rice. We focused on four key aspects: screening and breeding of ratoon rice cultivars and the classification; suitable stubble height for mechanically harvested ratoon rice, as well as water and fertilizer management; dry matter production and allocation in ratoon rice and the relationship with yield formation; regenerative activity and vigor of ratoon rice roots and their relationship with rhizosphere micro-ecological characteristics. As for the extending of mechanized low-cut stubbles ratoon rice technique, we should properly regulate the rhizosphere system, coordinate rhizosphere nutrient supply, germination of axillary buds, and tillering regeneration, to achieve the target of "four-high-one-low", that is high regeneration coefficient, high number of regeneration panicle, high harvest index, high yield, high quality, low-carbon and safe, aiming to improve the sustainability of ratoon rice industry.

[Molecular cloning and expression analysis of an Aux/IAA gene (RgIAA1) from Rehmannia glutinosa].

To clone and analyze a member of the Auxin/indole-3-acetic acid (Aux/IAA) gene family, RgIAA1, from Rehmannia glutinosa. The transcriptional EST database of R. glutinosa was used to clone the new Aux/IAA gene by cDNA probe of AtIAA14. Bioinformatics was applied to analyze the sequence characteristics of RgIAA1 protein and construct phylogenetiC trees. Quantitative RT-PCR has been applied to detect the transcription level of RgIAA1 in seven tissues as well as in leaves under three stresses. The results showed that, the cDNA sequence of RgIAA1 contains 903 bp was obtained. The open reading frame (ORF) of RgIAA1 was 681 bp encoding 226 amino acids, which has typical structural domains and characteristic sequence of Aux/IAA family proteins. RgIAA1 showed the highest expression level in unfolded leaf, followed by the stem. And the expression of RglAA1 was quickly decreased with leaf growing up. The transcription level increased under continuous cropping conditions while it reduced both in salinity and waterlogging stresses. RgIAA1, an Aux/IAA gene from R. glutinosa has been obtained for the first time, which can lay the foundation for further studies about its molecular function in development and responses to stress.

[Field greenhouse gas emission characteristics and carbon footprint of ratoon rice]. / 再生稻田温室气体排放特征及碳足迹.

It is of great significance to understand the effects of different rice cultivation methods in southeast China on greenhouse gas emission characteristics and carbon footprint of paddy fields during rice cultivation for rice sustainable production. In this study, the popular conventional rice 'Jiafuzhan' and hybrid rice 'Yongyou 2640' were used as materials to establish four rice cultivation patterns suitable for different ecological types in Fujian Province: 1) double-cropping system, early rice and late rice with Jiafuzhan (D-J); 2) early maturing ratooning system, first season rice and ratooning season rice with Jiafuzhan (R-J); 3) middle-maturing ratooning system, first season rice and ratooning season with Yongyou 2640 (R-Y); and 4) single cropping system with Yongyou 2640 (S-Y), which should be synchronized in heading time with the counterpart (the ratooning season rice). Greenhouse gas emissions from paddy soil were measured by the closed static black box observation method and the gas chromatography method, respectively. The total direct and indirect greenhouse gas emissions (carbon footprints) from different rice farming patterns were evaluated by using the life cycle analysis. The results showed that greenhouse gas emissions in different rice cropping systems were lower in the early growth stage, then decreased after reaching the peak at the booting stage, demonstrating a double peak curve in the whole growth stage, in which the first peak was higher in early season or first season than the second peak in the late season or ratooning season in the cropping patterns. Moreover, the total greenhouse gas emissions were significantly different among cropping systems. The global warming potential (GWP) of different cropping patterns was in order of R-Y>D-J>S-Y>R-J, while the annual greenhouse gas emission intensity (GHGI) was D-J>S-Y>R-Y>R-J. GWP and GHGI of the ratooning system decreased by 26.1% and 14.1%, respectively, compared with those of the double-cropping system. The same pattern was observed in the ratooning rice of Yongyou 2640, which were decreased by 74.3% and 56.7%, respectively, compared with the counterpart, Yongyou 2640 in a single-cropping system synchronized heading. Carbon footprint of rice per unit yield ranged from 0.38-1.08 kg CO2-eq.·kg-1 under the different cropping systems, of which the carbon footprint of rice per unit yield was the highest under the double cropping system compared with that under other cropping systems. The reverse was true in the case of carbon footprint of rice per unit yield under the ratooning system with Yongyou 2640. Additionally, the main source of carbon footprint of different rice cropping patterns was CH4, contributing 44.2%-71.5%, suggesting that rice ratooning system could significantly reduce global warming potential and carbon emission intensity of rice in comparison with other cropping patterns. Therefore, it is key to select rice varieties with high yield and low carbon emission and to establish the supporting scientific cultivation techniques for effective reduction of CH4 emission and carbon footprint of paddy fields and promotion of ratooning rice production.

[Changes in physicochemical property and microbial community of Pseudostellaria heterophylla soil at diffe-rent fallow ages]. / 太子参不同休耕年限土壤理化特征和微生物群落变化.

Pseudostellaria heterophylla is authentic traditional Chinese herbal medicine in Fujian Province. P. hete-rophylla suffers from serious consecutive monoculture problems. Fallow can alleviate such problems, but the mecha-nism is still unclear. In this study, high-throughput sequencing was performed to analyze the changes in soil microbial community structure and diversity in the P. heterophylla soil at different fallow ages as well as their relationships with soil physicochemical properties and phenolic acids. The results showed that fungal community diversity decreased but bacterial community diversity increased in fallow soils compared with the control soil of P. heterophy-lla. For bacterial communities, the relative abundance of Acidobacteria increased, while that of Proteobacteria and Actinobacteria decreased in fallow soils. For fungal communities, the relative abundance of dominant phyla had no significant difference between fallow and control soils. Soil acidity and organic matter content showed a trend of weakening and decreasing, respectively, with the increases of fallow years. In addition, with the increases of fallow years, the content of phenolic acids in soil, including benzoic acid and salicylic acid, showed significant decrease, while some other phenolic acids such as p-coumaric acid were accumulated obviously. Taken together, fallow could efficiently ameliorate the structure of soil microbial community and soil properties of P. heterophylla, and thus alleviate the effects of continuous cropping.

Characterization of metaproteomics in crop rhizospheric soil.

Soil rhizospheric metaproteomics is a powerful scientific tool to uncover the interactions between plants and microorganisms in the soil ecosystem. The present study established an extraction method suitable for different soils that could increase the extracted protein content. Close to 1000 separate spots with high reproducibility could be identified in the stained 2-DE gels. Among the spots, 189 spots representing 122 proteins on a 2-DE gel of rice soil samples were successfully identified by MALDI-TOF/TOF-MS. These proteins mainly originated from rice and microorganisms. They were involved in protein, energy, nucleotide, and secondary metabolisms, as well as signal transduction and resistance. Three characteristics of the crop rhizospheric metaproteomics seemed apparent: (1) approximately one-third of the protein spots could not be identified by MALDI-TOF/TOF/MS, (2) the conservative proteins from plants formed a feature distribution of crop rhizospheric metaproteome, and (3) there were very complex interactions between plants and microorganisms existing in a crop rhizospheric soil. Further functional analysis on the identified proteins unveiled various metabolic pathways and signal transductions involved in the soil biotic community. This study provides a paradigm for metaproteomic research on soil biology.

Effects of different technical substitutions on reducing replant disease of Radix pseudostella-riae and the underlying mechanism.

Radix pseudostellariae is a traditional Chinese medicinical herb, with tuberous roots being used as a medicine. Serious continuous monoculture problems were suffered from process of artificial and intensive cultivation. To explore the effective technical methods to overcome the monoculture problems, the effects of different technical substitution patterns on soil environment remediation, photosynthetic physiology and yield performance of R. pseudostellariae were assessed under continuous cropping system with four technical substitution treatments in the phase between two crops after the newly harvested R. pseudostellariae (first crop): fallow (RP-F-RP), fallow treated with microbial fertilizer (RP-F-BF), water flooding (RP-WF), and water flooding treated with specific microbial fertilizer (RP-WF-BF). Results showed that RP-WF-BF pattern was the single one that could effectively restore R. pseudostellariae yield under two-year monoculture and three-year monoculture to more than 90% and 70% of the newly planted respectively. All the other patterns did not significantly improve R. pseudostellariae yield under two-year monoculture. The contents of polysaccharide and total saponin in R. pseudostellariae under RP-WF-BF treatment were significantly increased by 15.3% and 16.5% compared with those of the newly planted, respectively. The abundance of beneficial microorganisms in the rhizosphere soil of R. pseudostellariae significantly increased. A reverse pattern occurred for pathogens under RP-WF-BF pattern. Moreover, soil nitrogen cycling was improved. The expression of AOB, nosZ and nirK was increased by 931%, 124% and 100% compared with those in the RP-F-RP pattern, respectively. Soil acidification under RP-WF-BF pattern was alleviated. The alleviation of soil biological and abiotic stress enhanced the stability of the antioxidant enzyme system, thereby improving the growth and development of R. pseudostellariae at the seedling and the early expand stages. The chlorophyll content, leaf area index and photosynthesis rate of leaves were increased, with the dry matter translocation improved and accumulation of underground dry matter accelerated, which ultimately increased yield and quality under RP-WF-BF pattern. In this study, the separate water flooding treatment (RP-WF) and microbial fertilizer treatment (RP-F-BF) failed to significantly reduce the continuous cropping obstacles of R. pseudostellariae, while the combination of them could produce a multiplication effect of sustainable strengthening on rhizosphere environment. The findings suggested that effective technical substitution could reduce replant disease of R. pseudostellariae.

[Evolution mechanism of ecosystem service value at the township-scale in Anxi County of Fujian Province, China]. / 福建安溪县乡镇土地生态系统服务价值的演变机制.

To clarify the interaction between land-use change and ecosystem service, the traditional ecosystem service valuation model was modified using the adjustment coefficients of biomass factor and socio-economic factor to evaluate ecosystem service value (ESV) of 24 towns in Anxi County from 1999 to 2019, aiming to understand the ecological response to land-use change. The results showed that ESV of 24 towns in Anxi County decreased gradually during the study period, with a decrease of 0.004 to 0.295 million yuan. Forestland and cultivated land made the largest contribution to ESV, followed by grassland and water bodies, whereas the contribution of other land types were negative. ESV could be increased by converting other land types into forestland, but be decreased by converting other land types into orchard land area (mainly tea plantation). The chemical fertilizer-monoculture management pattern of ratooning tea plantation reduced ESV, while the ecological cultivation of tea plantation could effectively improve soil microbial diversity and soil fertility, and finally enhance ESV.

[Effects of exogenous microorganisms on seedling growth and soil microbial community of Casuarina equisetifolia]. / 外源微生物对木麻黄幼苗生长和土壤微生物群落的影响.

With a pot experiment, the Biolog microplate and phospholipid fatty acid (PLFA) technology were used to explore whether the application of bacteria, Bacillus amyloliquefaciens (YB706) and Burkholderia (BK8), could improve the soil nutrient, microbial community and growth of Casuarina equisetifolia. The results showed that the concentrations of soil alkali-hydrolyzed nitrogen and available phosphorus of C. equisetifolia treated with YB706 and BK8 increased significantly compared with the control (CK), but the concentrations of total nitrogen, total phosphorus, total potassium and available potassium changed little, plant height increased by 59.1% and 63.9%, respectively, and the chlorophyll content of plant treated with BK8 increased by 81.9%. The average well color development values showed a pattern of YB706>CK>BK8. The utilization rate of different carbon sources showed the same trend except the amino acids. Both YB706 and BK8 treatments significantly increased the richness and quantity of soil microorganisms. The PLFA of all kinds of microorganisms was BK8>YB706>CK except actinomycetes. The ratio of soil fungi to bacteria was increased compared with CK. The Simpson, Shannon, Brillouin and McIntosh indices of rhizosphere soil microbial community in YB706 and BK8 treatments were significantly increased. Our results suggested that application of YB706 and BK8 could improve the growth rate of C. equisetifolia seedlings, effectively increase the contents of soil available nutrients, increase soil microbial diversity, and improve soil microbial environment.

[Effects of Rehmannia glutinosa consecutive monoculture on the community structure and diversity of phyllosphere bacteria]. / åœ°é»„è¿žä½œå¯¹å¶é™ ç»†èŒç¾¤è½ç»“æž„åŠå¤šæ ·æ€§çš„å½±å“.

Rehmannia glutinosa, a perennial herbaceous species, belongs to the family Scrophularia-ceae. As a staple medicinal material, its tuberous roots are highly valued in traditional Chinese medicine. However, R. glutinosa suffers from serious consecutive monoculture problems in production, which leads to a decline in both productivity and quality. Phyllosphere bacteria, the most abundant component of phyllosphere microorganisms, play crucial roles in plant growth and health. Characterization of phyllosphere bacteria could provide new insights into the mechanisms of consecutive monoculture problems and their control measures. Meanwhile, the varied taxa could be served as an important indicator of consecutive monoculture problems. The barcoded pyrosequencing of 16S rDNA genes combined with a culture-dependent approach was applied to characterize the shifts of bacterial community structure and diversity in the phyllosphere under consecutive monoculture of R. glutinosa. The results showed that consecutive monoculture clearly affected bacterial community structure in the phyllosphere. The phyllosphere bacterial communities of the two-year monocultured (TY) and the diseased plants (DP) were more similar, and different from the one-year monocultured (OY). The evenness, Shannon and Simpson diversity indices were significantly lower in TY and DP than in OY. Species annotation showed that bacterial community in R. glutinosa phyllosphere mainly consisted of Proteobacteria (91.2%), Firmicutes (5.1%) and Actinobacteria (3.7%). There was no significant difference in the number of detected bacterial taxa. However, Proteobacteria was significantly increased while Firmicutes and Actinobacteria were significantly decreased under consecutive monoculture. At the genus level, the relative abundances of genera Exiguobacterium, Bacillus and Arthrobacter, potentially beneficial microorganisms, were significantly higher in OY than that in TY and DP, but it was opposite for the genus Pseudomonas. The results from the culture-dependent approach and pathogenicity test showed that Pseudomonas plecoglossicida D9, widely isolated from the diseased leaves, was highly pathogenic to leaves. In conclusion, R. glutinosa monoculture resulted in distinct phyllosphere bacterial community variation with the accumulation of pathogen loads at the expense of beneficial microorganisms, which could contribute to the occurrence of leaf disease symptoms,and aggravate R. glutinosa replant disease in a monoculture regime.

[Effects of biochar and sheep manure on rhizospheric soil microbial community in continuous ratooning tea orchards]. / æ–½ç”¨ç”Ÿç‰©è´¨ç‚­å’Œç¾Šç²ªå¯¹å®¿æ ¹è¿žä½œèŒ¶å›­æ ¹é™ åœŸå£¤å¾®ç”Ÿç‰©çš„å½±å“.

Long-term continuous ratooning of tea could lead to serious soil acidification, nutritional imbalance, and the deterioration of the rhizosphere micro-ecological environment. Understanding the effects of biochar and sheep manure on the growth of tea plants and the rhizosphere microbial community structure and function would provide theoretical basis to improve the soil micro-ecological environment of continuous ratooning tea orchards. Biolog technology combined with phospholipid fatty acid (PLFA) approaches were employed to quantify the effects of biochar (40 t·hm-2) and sheep manure on the growth of 20 years continuous ratooning tea plants, soil chemical properties, and the soil microbial community structure and function. The results showed that after one year treatment, biochar and sheep manure both improved soil pH and nutrition, and significantly enhanced tea production. Compared with the routine fertilizer application (CK), the biochar and sheep manure treatments significantly increased the carbon metabolic activity (AWCD) and microorganism diversity in the rhizosphere soils, and increased the relative utilization of the carbon sources such as amines, carbohydrates, and polymers. The total PLFA concentrations in the biochar and sheep manure treatments were significantly increased by 20.9% and 47.5% than that in the routine fertilizers application. In addition, sheep manure treatment significantly decreased the saturated/monosaturated fatty acids In conclusion, biochar and sheep manure could alleviate soil acidification, enhance soil nutrition and the growth of tea plants. Both management strategies could increase the soil microbial activity and biomass, enhance the diversity, and improve the microbial community structure, which could be taken as effective measures to regulate the rhizosphere micro-environment of tea plants.

[The differential expression of the genes of the key enzymes involved in phenolic compound metabolism in rice (Oryza sativa L.) under different nitrogen supply].

Differential expression of the key genes controlling phenolic metabolism in allelopathic and non-allelopathic rice accessions was investigated under two nitrogen supply levels (lower and normal) using fluorescence quantitative-polymerase chain reaction (FQ-PCR) (Figs.2, 3). The results indicated that 9 key enzyme genes concerned were mediated by lower nitrogen level (Table 2). All of the nine genes (Table 1, Fig.4), were up-regulated by 1.9-5.4 times of the relative gene expression amounts in allelopathic rice accession, 'PI312777' under the lower nitrogen condition compared with their controls, of which PAL gene showed the highest relative gene expression amount with 5.4 times of the relative gene expressions compared with the control, while in non-allelopathic rice Lemont, seven genes were down-regulated by 29%-72% under lower nitrogen supplies compared with their controls and only two genes, i.e., phenylalanine ammonia-lyase and cinnamoyl-CoA genes were up-regulated, which however were a decrease of 22% and 74% over those in allelopathic rice accession (Table 2). These findings strongly suggest that the increase of allelopathic potential induced by 1/4 nutrient stress was responsible for enhanced phenolic compound synthesis metabolism.

[Effects of fertilizer application on contents of 2-undecanone and soluble carbonhydrate in Houttuynia cordata with different fertilizers].

OBJECTIVE: To investigate the effect of five kinds of fertilizers at three application levels on the content of 2-undecanone and carbohydrate in Houttuynia cordata. METHOD: A single factor randomized block design was used to investigate the content of 2-undecanone and carbohydrate in the plant. RESULT: The results showed that the content of 2-undecanone was the highest both in aerial and underground parts of H. cordata, which was fertilized with complex fertilizers served in conventional way, having the content 18.6 microg g(-1) and 26.0 microg g(-1) respectively. In addition, 2-undecanone contents in aerial parts of H. cordata (14.9 microg g(-1)) fertilized with manure of human were also higher than that with chemical fertilizer, pig and duck manures, but no significant difference were found among the other treatments in aerial or underground parts of the plants, respectively. The results also demonstrated that fertilized with organic fertilizer might be beneficial to enhance the quality of sugar in H. cordata, mainly including the contents of total sugar, solutable sugar, fructose and reduced sugar in the plants, especially with manure of human and pig. CONCLUSION: As the result of this study and the related previous research on yield of H. cordata were considered, the fertilizing ways for increasing quality of H. cordata should take the manure of human as a main fertilizer and mix with the other organic fertilizers, complex fertilizers and chemical ones may be needed to balance the plant nutrient. In the field practice, the amount of organic fertilizer including 108,000 kg hm(-2) human mature, together with some high-efficient complex fertilizer and a small amount of quick-acting chemical fertilizer is recommended.

[The distribution of ATPase in developmental anther of rice].

The distribution of ATPase was studied using lead precipitation technique during anther development in rice. The ATPase reactive precipitates (ppts) were located mostly in the nucleus of microspore mother cells (MMC) and only a few in the cytoplasm (Plate I-1). Anther wall had differentiated into four layers of cells and a few precipitates were located in the cells except the nucleus of tapetal cells where there were many ATPase reactive precipitates (Plate I-2). After meiosis of MMC, tapetal cells formed many endoplasmic reticula in its cytoplasm but still contained a few ppts. In the cells of epidermis, endothelium and middle layer, the ppts increased evidently in plasma membrane and near cytoplasm than before (Plate I-5). There were a large number of ppts located in the pollen wall during pollen development (Plate I-6), suggesting that ATPase is necessary for the construction of pollen wall. The exine of pollen wall of rice was constructed during microspore development and consisted of sporopollenin which came from tapetal cells. The ppts in exine also came from tapetal cell (Plate II-7). The intine of pollen wall was constructed during the stage of 2-cellular pollen and consisted of cellulose material coming from vegetative cell of pollen. The ATPase and ppts in intine came from vegetative cell of pollen (Plate III-7). Vegetative cell contained more ppts than generative cell during the development of 2-cellular pollen (Plate II-4, 5). The amount of ppts between two sperm cells in a pollen grain was also different (Plate IV-3,4). The physiological functions of ATPase located in different cells and different parts in the cells during anther development of rice were analyzed.

[Effects of different amendments on contents of phenolic acids and specific microbes in rhizosphere of Pseudostellaria heterophylla.] / ä¸åŒæ”¹è‰¯æŽªæ–½å¯¹å¤ªå­å‚æ ¹é™ åœŸå£¤é šé ¸å«é‡åŠç‰¹å¼‚èŒç¾¤çš„å½±å“.

Pseudostellaria heterophylla is a perennial herbaceous plant in the family Caryophyllaceae. The tuberous roots of P. heterophylla are highly valued in traditional Chinese medicine and have a high market demand. However, extended monoculture of P. heterophylla results in a significant decline in the biomass and quality, and escalates disease and pest problems. Therefore, it is important to understand the underlying mechanism and biocontrol methods for consecutive monoculture problems. With "Zheshen 2" as an experimental material, the changes in the contents of main nutrients in soil, phenolic acids and specific microbes under monoculture and different amendments were analyzed by using high performance liquid chromatography (HPLC) and qPCR. The results showed that consecutive monoculture of P. heterophylla led to a decrease in yield by 43.5% while the microbial fertilizer treatment and the paddy-upland rotation could relieve the consecutive monoculture problems. Available nitrogen, available phosphorus, available potassium and total potassium were significantly higher in the consecutively monocultured soils than in the newly planted soils. But consecutive monoculture resulted in soil acidification. HPLC analysis showed that conse-cutive monoculture of this plant did not lead to a consistent accumulation of soil phenolic acids. At middle stage of root expansion and at harvest stage, most of phenolic acids were even higher in the newly planted soils than in the consecutively monocultured soils. Furthermore, qPCR analysis showed that the amounts of three specific pathogens identified previously (i.e. Fusarium oxysporum, Talaromyces helicus, Kosakonia sacchari) were significantly higher in the consecutively monocultured soils than in the newly planted soils. However, the microbial fertilizer treatment and the paddy-upland rotation resulted in a significant decline in the population of these specific pathogens and improved the soil environment. In conclusion, the consecutive monoculture problems of P. heterophylla may be due to the rapid proliferation of host-specific pathogens, rather than the deficiency of soil nutrients and the autotoxicity of allelochemicals in root exudates. The results in this study could provide the theoretical basis to explore the underlying mechanism of replanting disease of P. heterophylla and its biocontrol strategies.

[Assesment of genetic diversity of allelopathic rice germplasm based on RAPD and ISSR].

Random Amplified Polymorphic DNA (RAPD) and Inter-simple Sequence Repeat (ISSR) methods were used to detect the genetic diversity of 57 allelopathic rice accessions which were introduced from 10 countries or areas. A total of 12 RAPD primers and seven ISSR primers were indentified with polymorphism among the entries. For RAPD markers, 85 polymorphic bands were produced, percentage of polymorphic bands (PPB) were 69.4%. For ISSR marker, 34 polymorphic bands were generated, PPB were 53.0%. The result from the clustering analysis by UPGMA indicated that those accessions from the same geographical location were clustered into one group. It was also found that some rice accessions with higher allelopathic potential were clustered together, implying that the genes conferring allelopathy in those rice accessions might be isolocus. However, some rice accessions with different allelopathic potential clustered into the same group performed lower level of generic polymorphism which was attributed to oriented selection for other traits in breeding program. The estimates of correlation coefficient of RAPD and ISSR based on the genetic similarity matrices were significantly correlated.