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Vegetation photosynthesis is a critical component of terrestrial carbon cycles, and its peak value (peak photosynthetic rate) dominates plant CO2 uptake. Urbanization has significantly influenced vegetation photosynthesis by changing environmental conditions directly (replacement of vegetated surfaces with impervious surfaces) and indirectly (e.g., atmospheric and climatic conditions). Although some studies have investigated the effects of urbanization on vegetation productivity across the whole study area, how the peak photosynthetic rate responds to urbanization for different vegetation types has received scant scholarly attention. Here, using the urban-rural gradient approach, we explored the effects of urbanization on the peak photosynthetic rate (surrogated by GPPmax and EVImax) of different vegetation types across urbanization intensity (UI) gradients in the Yangtze River Delta Urban Agglomeration (YRDUA). The results showed that (1) the GPPmax and EVImax of the forest, grassland, and wetland decreased with urban intensity. GPPmax and EVImax in rural areas (UI ≦ 1%) were 36.62 and 30.47% higher than those of urban areas (UI > 1%) overall vegetation types. (2) The indirect impacts can offset or exacerbate the direct loss of vegetation photosynthesis caused by urbanization in YRDUA. Especially for forest ecosystems in YRDUA, the negative direct urbanization effect is exacerbated by the indirect reduction in vegetation growth. However, the indirect effects of urbanization on grassland and wetland offset 47.08 and 87.23% loss of GPPmax, and 34.17 and 79.73% loss of EVImax due to the reduction of vegetated surface area, respectively. (3) The indirect impact of urbanization on vegetation photosynthesis was dominated by the elevated daytime land surface temperature (LSTday). Our study highlights the necessity of distinguishing the various effects of urbanization on vegetation photosynthesis, which may help stakeholders formulate more reasonable urban environmental planning.

Eclipta, widespread in tropical, subtropical, and temperate regions, is one of the main malignant broadleaf weeds and thrives in moist and dryland fields. Field rates of acetolactate synthase (ALS) inhibitors have failed to control eclipta in some farmlands in China. One ALS inhibitor–resistant population (R) collected from Jiangsu province in China was confirmed in the greenhouse in our preliminary work. Whole-plant assays revealed that this R population was highly resistant to four sulfonylureas (pyrazosulfuron-ethyl, 134-fold; bensulfuron-methyl, 172-fold; metsulfuron-methyl, 30-fold; and tribenuron-methyl, 195-fold), two triazolopyrimidines (pyroxsulam, 98-fold; penoxsulam, 30-fold), and one pyrimidinylthio-benzoate (bispyribac-sodium, 166-fold) and was moderately resistant to two imidazolinones (imazethapyr, 10-fold; imazapic, 19-fold). ALS enzyme-activity assays showed insensitivity of the ALS from the R population (resistance index values ranged from 12 to 293) to all of the above ALS inhibitors in vitro. Chromatograms from ALS gene sequence analysis detected a homozygous Pro-197-Ser amino acid substitution in the R population. These results confirmed that the Pro-197-Ser substitution results in broad-spectrum cross-resistance to ALS inhibitors in the eclipta R population. To our knowledge, this study is the first to report broad cross-resistance to ALS inhibitors in eclipta and to obtain the full-length ALS gene sequence.Nomenclature: bensulfuron-methyl; bispyribac-sodium; imazapic; imazethapyr; metsulfuron-methyl; penoxsulam; pyrazosulfuron-ethyl; pyroxsulam; tribenuron-methyl; eclipta, Eclipta prostrata (L.) L.

MicroRNAs (miRNAs) have been shown to play important roles in plant development, growth and stress response. Sweet sorghum [Sorghum bicolor (L.) Moench] is an important source of bioenergy due to the high sugar content in its stems. However, it is not clear how the miRNA is involved in sugar accumulation in sorghum stems. In order to identify the miRNAs in the stems and the leaves of sweet sorghum, we extracted RNAs of the stems and leaves of sweet sorghum (Rio) and grain sorghum (BTx623) at the heading and dough stages for high-throughput sequencing. A total of 179279048 reads were obtained from Illumina-based sequencing. Further analysis identified nine known miRNAs and twelve novel miRNAs that showed significantly and specifically differentially expressed in the stems of sweet sorghum. The target genes of the differentially expressed novel miRNAs include the transcription factor, glucosyltransferase, protein kinase, cytochrome P450, transporters etc. GO enrichment analysis showed that the predicted targets of these differentially expressed miRNAs participated in diverse physiological and metabolic processes. We performed RT-qRCR analysis on these miRNAs across eight different libraries to validate the miRNAs. Finally, we screened stem-specifically expressed novel miRNA and a leaf-specifically expressed novel miRNA in sweet sorghum comparing with grain sorghum. Our results provide a basis for further investigation of the potential role of these individual miRNAs in sugar accumulation.

In our country, irrigation mode in the greenhouse is still flood irrigation, which not only wastes water resources in short supply, but also restricts the increase of the crop output and the improvement of its quality in the greeenhouse. The paper used sensor technology to real-time do acquisition of the temperature and humidity of air, the moisture content of soil and the illuminance in the greenhouse. The SCM (Single Chip Micyoco) gived a reasonable control decision by analysing these data to do automatically sprinkling irrigation by control the actuator. The system achieves computer automatic control, sprinkling irrigation by need, time and quantity. It is energy-saving, environmental protection, labor saving, so the system has a certain practicality and potential popularization. Keywords-greenhouse; sprinkling irrigation; water-saving; temperature; humidity