Carbon and nitrogen cycling in a tropical Brazilian soil cropped with sugarcane and irrigated with wastewater

Carbon (C) and nitrogen (N) dynamics in agro-systems can be altered as a consequence of treated sewage effluent (TSE) irrigation. The present study evaluated the effects of TSE irrigation over 16 months on N concentrations in sugarcane (leaves, stalks and juice), total soil carbon (TC), total soil nitrogen (TN), NO₃⁻-N in soil and nitrate (NO₃⁻) and dissolved organic carbon (DOC) in soil solution. The soil was classified as an Oxisol and samplings were carried out during the first productive crop cycle, from February 2005 (before planting) to September 2006 (after sugarcane harvest and 16 months of TSE irrigation). The experiment was arranged in a complete block design with five treatments and four replicates. Irrigated plots received 50% of the recommended mineral N fertilization and 100% (T100), 125% (T125), 150% (T150) and 200% (T200) of crop water demand. No mineral N and irrigation were applied to the control plots. TSE irrigation enhanced sugarcane yield but resulted in total-N inputs (804-1622 kg N ha⁻¹) greater than exported N (463-597 kg N ha⁻¹). Hence, throughout the irrigation period, high NO₃⁻ concentrations (up to 388 mg L⁻¹ at T200) and DOC (up to 142 mg L⁻¹ at T100) were measured in soil solution below the root zone, indicating the potential of groundwater contamination. TSE irrigation did not change soil TC and TN.     

Influence of morphometric parameters on the size of collateral ligaments of the distal interphalangeal joint of equines

The physiological measurements of collateral ligaments of distal interphalangeal joint (CL-DIPJ) differ in the literature. The factors that influence these differences are not well described. The aims of this study are to compare CL-DIPJ sizes in equines with different withers height, as well as to correlate body weight and hoof size to the size of these ligaments. In total, 52 horses were used in the study. They were divided into two groups according to wither height: Group 1 (G1) - 21 animals with up to 147 cm - and group 2 (G2) - 21 animals with greater than 148 cm. CL-DIPJ was ultrasonographically measured in order to find the mean of dorso-palmar (DPD) and latero-medial (LMD) diameters and the cross-sectional area (CSA). Hoof width and length were measured, and the results were used to calculate the hoof surface area. Withers height and body weight were also measured. Groups were statistically compared by Student's t test and Pearson's correlation application to each group. Groups were different in body size, HS and CL-DIPJ size when p < .05, except for the LMD of the medial collateral ligament of left thoracic limb. Withers height and body weight did not show significant correlations to CL-DIPJ size in G1, but they had little influence on the size of CL-DIPJ on G2. No correlation between the hoof size and the CL-DIPJ was noted in any of the two groups. In conclusion, the CL-DIPJ were larger in taller horses and their sizes were correlated to their height and weight, but they were not correlated to hoof size.     

基于RNA-Seq技术的甘蔗参考转录组建立及分析

本研究基于RNA-Seq技术建立了一个由3个甘蔗原始亲本和8个不同来源的甘蔗栽培品种/系构成的甘蔗参考转录组,并进行生物信息学相关分析。研究结果表明:对供试材料+1叶RNA混合样本进行转录组测序,可组装出98 945条Contig,从中找到5 806个SSR位点,其中三核苷酸重复最多、六核苷酸重复最少,CCG/CGG出现的频率最高。进一步处理Contig获得75 656条Unigene,将所有的Unigene与Nr数据库、Swiss-Prot数据库、KEGG数据库和COG数据库进行Blast,有53 951条Unigene得到注释。在Nr和KEGG注释结果基础上,对Unigene进行GO和KEGG功能分类,分别获得44个功能小组和123个Pathway注释。研究结果可为研究甘蔗在不同时空条件下的差异基因表达奠定基础。     

Nitrate accumulation,productivity and photosynthesis of Brassica alboglabra grown under low light with supplemental LED lighting in the tropical greenhouse

Abstract

Vegetables are a large source of nitrate (NO₃^?) in our diet. As NO₂^? is toxic to humans, it is undesirable to consume vegetables with high NO₃^? content. Therefore, this study aimed to investigate the effect of supplementing of red- and blue-LED lighting to B. alboglabra grown in the tropical greenhouse in terms of moderating NO₃^? accumulation, improving photosynthesis, and enhancing productivity. All plants were grown hydroponically in full nutrients under prevailing greenhouse conditions for 20?days (full sunlight). Thereafter, plants were subjected to three different light treatments for 12?days: full sunlight, shade, and shade supplemented with LEDs. The average midday photosynthetic photon flux density (PPFD) during the light treatment periods were 220?μmol m^?2 s^?1 (full sunlight), 55?μmol m^?2 s^?1 (shade), and 220?μmol m^?2 s^?1 (shade supplemented with LEDs). Shoot nitrate (NO₃^?) concentration increased significantly in plants grown in the shade. However, shoot NO₃^? concentration was reduced when plants were supplemented with red- and blue-LED lighting. Photosynthetic CO₂ assimilation, stomatal conductance, and productivity also improved in these plants. Our results suggest that supplemental red- and blue-LED lighting in a tropical greenhouse during periods of cloudy and hazy weather could improve productivity and nutrient quality of Chinese broccoli.     

Citrus black spot intensity and yield losses on sweet orange are affected by Phyllosticta citricarpa inoculum concentration and fruit developmental stage

Citrus black spot (CBS) symptom expression on sweet oranges has been reported to be affected by the fruit developmental stage and inoculum concentration in greenhouse conditions. However, there is little information concerning the period in which the fruit is susceptible in commercial orchards. This study assessed the influence of fruit age and inoculum concentration of Phyllosticta citricarpa on CBS intensity and fruit drop in the field. Two field trials were conducted in commercial ‘Valencia’ orchards in São Paulo state, Brazil. Fruit were inoculated from October (petal fall stage) to July (c.6.5 cm diameter), with 10¹, 10³ and 10⁵ pycnidiospores/ml. CBS symptoms and fruit drop were observed in higher levels for fruit inoculated from October to February than from March to July. In both trials, when fruit were inoculated 10 times from October to July or single-inoculated in November or December, high CBS severities of 11%–22% were observed and the proportion of fruit remaining on the tree was 48%–77%; in contrast, noninoculated fruit had severity below 1.1% and 90% remained on the tree. Inoculations in November or December of green fruit with 1.5–3.0 cm diameter using 10⁵ pycnidiospores/ml were associated with higher CBS intensity and fruit drop and shorter incubation period than inoculations with lower concentrations. This work provides a better understanding of fruit stages and P. citricarpa inoculum concentrations most related to symptom expression and losses under natural conditions and may be helpful for improvement of CBS management in the São Paulo citrus belt.