Stable isotope variations in particulate organic matter and a planktivorous fish in the Yangtze River

Temporal and spatial changes in delta(13) C and delta 15 N of particulate organic matter (POM) and Hemiculter leucisculus were studied in the Yangtze River of China. Isotopic signatures of POM showed seasonal variations, which was assumed to be associated with allochthonous organic input and autochthonous phytoplankton growth. delta C-13 of H. leucisculus was 1.1 % higher than that of POM, which suggested that the food source of H. leucisculus was mostly from the POM. A mass balance model indicated the trophic position of H. leucisculus in the food web of Yangtze River was estimated to be 2.0 - 2.1, indicating that this fish mainly feeds on planktonic organic matter, which agreed with previous gut content analysis.Temporal and spatial changes in delta(13) C and delta 15 N of particulate organic matter (POM) and Hemiculter leucisculus were studied in the Yangtze River of China. Isotopic signatures of POM showed seasonal variations, which was assumed to be associated with allochthonous organic input and autochthonous phytoplankton growth. delta C-13 of H. leucisculus was 1.1 % higher than that of POM, which suggested that the food source of H. leucisculus was mostly from the POM. A mass balance model indicated the trophic position of H. leucisculus in the food web of Yangtze River was estimated to be 2.0 - 2.1, indicating that this fish mainly feeds on planktonic organic matter, which agreed with previous gut content analysis

Effect of Banana Stalk Organic Fertilizer on the Growth of Chinese Cabbage

In order to solve the problem of waste disposal after banana harvest, we use banana stalk to produce banana stalk organic fertilizer, through a plot experiment. We compare the influence of normal organic fertilizer (Wanlubao) and banana stalk organic fertilizer as base fertilizers on Chinese cabbage growth, and evaluate the economic benefits of banana stalk organic fertilizer. The results show that organic fertilizer has little effect on water content and nutrient content of Chinese cabbage, but has significant effect on plant height and leaf width. Using organic fertilizer can increase the production of Chinese cabbage by 22.50%-43.10%. With 6750 kg/ha normal organic fertilizer, Chinese cabbage gets the highest yield, which reaches 30135 kg/ha, followed by the treatment of 6750 kg/ha stalk organic fertilizer. At farmers’ conventional fertilization level (4500 kg/ha), stalk organic fertilizer can increase the yield by more than 3.50% in comparison with the normal organic fertilizer, and the economic benefit increases by 1800 yuan/ha. As a kind of banana waste cycling product, banana stalk organic fertilizer is of low cost and good effect, and can be used instead of normal organic fertilizer

Molecular Markers and a Quality Trait Evaluation for Assessing the Genetic Diversity of Avocado Landraces from China

Avocado is an economically important crop that is widely cultivated in the tropical and subtropical regions of China. However, there is a lack of sufficient information regarding the racial origins and genetic diversification of native avocado germplasm. On the basis of a race-specific kompetitive allele-specific PCR genotyping analysis, the 56 avocado accessions examined in this study were classified as complex hybrids, namely Guatemalan × Mexican × West Indian hybrids. The genetic relationships among the avocado accessions were assessed based on a quality trait evaluation and molecular characterization. The total flavonoid content was relatively useful for differentiating between native avocado accessions. A cluster analysis as well as principal component and coordinate analyses of quality traits and molecular characteristics differentiated the avocado accessions, but not according to geographical origins. Thus, the artificial flow of avocado germplasm or seed exchanges among farmers within specific regions may have contributed to the similar genetic backgrounds of avocado germplasm from different collections

Interactions of Tomato Chlorosis Virus p27 Protein with Tomato Catalase Are Involved in Viral Infection

Tomato chlorosis virus (ToCV) severely threatens tomato production worldwide. P27 is known to be involved in virion assembly, but its other roles in ToCV infection are unclear. In this study, we found that removal of p27 reduced systemic infection, while ectopic expression of p27 promoted systemic infection of potato virus X in Nicotiana benthamiana. We determined that Solanum lycopersicum catalases (SlCAT) can interact with p27 in vitro and in vivo and that amino acids 73 to 77 of the N-terminus of SlCAT represent the critical region for their interaction. p27 is distributed in the cytoplasm and nucleus, and its coexpression with SlCAT1 or SlCAT2 changes its distribution in the nucleus. Furthermore, we found that silencing of SlCAT1 and SlCAT2 can promote ToCV infection. In conclusion, p27 can promote viral infection by binding directly to inhibit anti-ToCV processes mediated by SlCAT1 or SlCAT2

Cultivation and Management Technologies for New Banana Cultivar ‘Refen 1’(Musa Spp. ABB, Pisang Awak Subgroup)

Banana is one of the most important crops in tropical and subtropical regions of China. Fenjiao (Musa Spp. ABB,Pisang Awak subgroup) has been grown by small scale famers because of its stable market price and better sugar-acid blend. However, the traditional Fenjiao variety is susceptible to banana Fusarium wilt, has a high plant height (over 5.0 m), and farmers lack large-scale planting techniques. Based on the traditional Fenjiao variety, we selected ‘Refen 1’ variety through mutagenesis technology, which has low temperature resistance, suitable to marginal soils and relatively low plant height (3.2-4.0 m).This paper mainly introduces the major techniques of propagation, cultivation, and post-harvest stages of ‘Refen 1’ banana, including the selection of explant materials, treatment, disinfection, initial culture, nursery hardening of in vitro-produced banana plants, and transplant of tissue culture seedlings. The major points of the cultivation technology include banana plantation selection and preparation, planting methods, irrigation and fertilizer management, pruning and retaining, and prevention and control of plant diseases and insect pests

Transcriptome Profiling Provides Insight into the Genes in Carotenoid Biosynthesis during the Mesocarp and Seed Developmental Stages of Avocado (Persea americana)

Avocado (Persea americana Mill.) is an economically important crop because of its high nutritional value. However, the absence of a sequenced avocado reference genome has hindered investigations of secondary metabolism. For next-generation high-throughput transcriptome sequencing, we obtained 365,615,152 and 348,623,402 clean reads as well as 109.13 and 104.10 Gb of sequencing data for avocado mesocarp and seed, respectively, during five developmental stages. High-quality reads were assembled into 100,837 unigenes with an average length of 847.40 bp (N50 = 1725 bp). Additionally, 16,903 differentially expressed genes (DEGs) were detected, 17 of which were related to carotenoid biosynthesis. The expression levels of most of these 17 DEGs were higher in the mesocarp than in the seed during five developmental stages. In this study, the avocado mesocarp and seed transcriptome were also sequenced using single-molecule long-read sequencing to acquired 25.79 and 17.67 Gb clean data, respectively. We identified 233,014 and 238,219 consensus isoforms in avocado mesocarp and seed, respectively. Furthermore, 104 and 59 isoforms were found to correspond to the putative 11 carotenoid biosynthetic-related genes in the avocado mesocarp and seed, respectively. The isoform numbers of 10 out of the putative 11 genes involved in the carotenoid biosynthetic pathway were higher in the mesocarp than those in the seed. Besides, alpha- and beta-carotene contents in the avocado mesocarp and seed during five developmental stages were also measured, and they were higher in the mesocarp than in the seed, which validated the results of transcriptome profiling. Gene expression changes and the associated variations in gene dosage could influence carotenoid biosynthesis. These results will help to further elucidate carotenoid biosynthesis in avocado