Abstract Optimum irrigation scheduling is important for ensuring high yield and water productivity in substrate-cultivated vegetables and is determined based on information such as substrate water content, meteorological parameters, and crop growth. The aim of this study was to determine a precise irrigation schedule for coconut coir culture in a solar greenhouse by comparing the irrigation, evapotranspiration (ET), substrate water content (VWC), as well as the crop growth indices and yield of cucumber, and irrigation water productivity (IWP) under three irrigation schedules: the soil moisture sensor-based method (T-VWC), the accumulated radiation combined with soil moisture sensor-based method (Rn-VWC), and the crop evapotranspiration estimated method using the hourly PM-ETo equation with an improved calculation of Kc (T-ETc). The results showed that the daily irrigation and evapotranspiration amount were the highest under T-VWC treatment, while the lowest under T-ETc treatment. In different meteorological environments, the change in irrigation amount was more consistent with the ET,and the VWC was relatively stable in T-ETc treatment compared with that under T-VWC or Rn-VWC treatments. The plant height, leaves number, leaf area, and stem diameter of T-VWC and Rn-VWC treatments were higher than those of the T-ETc treatments, but there was no significant difference in cucumber yield. Compared with the T-VWC treatment, total irrigation amount under Rn-VWC and T-ETc treatments significantly decreased by 25.75% and 34.04%, respectively ( $$\hbox {P}<0.05$$ P < 0.05 ). The highest IWP values of 25.07 kg m $$^{-3}$$ - 3 was achieved from T-ETc treatment with significantly increasing by 44.33% compared to the T-VWC treatment (17.37 kg m $$^{-3}$$ - 3 ). In summary, the T-ETc treatment allowed more reasonable irrigation management and was appropriate for growing cucumber in coconut coir culture.

Large-scale greenhouse can be expected to serve as the future direction in the horticulture industry. However,the multi-span greenhouses can consume a large amount of energy for heating in winter in northern China, resulting in low profitability and sustainability. In this study, a multi-span greenhouse was designed with large roofs and external insulation, in order to reduce the heat loss of the greenhouse roof. The external insulation system was innovatively applied to the multi-span greenhouse. The greenhouse design was expected to improve thermal insulation performance and reduce heating energy consumption. A field test was carried out in Shouguang, Shandong Province, China. Taking the Venlo-type multi-span greenhouse in the same area as a reference, a systematic investigation was made on the light and thermal environment, thermal insulation performance of the multi-span greenhouse with external insulation. The experimental data were analyzed from continuous 40 winter days. The results show that: 1) The average solar radiation was 152 W/m~2 above the crop canopy inside the tested greenhouse during the day（10: 00-16: 00）, and the total light transmittance was 40%, which was 7 percentage points higher than that of Venlo type multi-span greenhouse. The best daylighting was found in the middle of the greenhouse span, due to the influence of the gutter. The solar radiation intensity at the east and west of the greenhouse span and under the gutter was reduced by 17%, 29%, and 46%,respectively, compared with the middle. 2) There was the folded in turn for the external thermal blankets covering the east and west greenhouse roofs after the sun rose. Specifically, the indoor air temperature rose at 1.9 ℃/h from 09:30 to 12:00, which was 0.3 ℃/h slower than that of the Venlo-type one. However, the sudden drop in the air temperature of the multi-span greenhouse with the external insulation was reduced by 0.3℃ within 10 min after folding insulation devices. The tested greenhouse was heated by the internal air circulation, with the air coming out from the ground and then returning to the equipment room through the inner side windows. During the heating period（20:00-07:00）, the average temperature difference of indoor air in the horizontal direction did not exceed 1.2 ℃, without exceeding 1.0 ℃in the vertical direction. The uniform distribution was observed in the horizontal temperature of the multi-span greenhouse with the external insulation. The vertical temperature difference was smaller than that of the Venlo-type one.3) The average air temperature at nighttime inside the multi-span greenhouse with external insulation ranged from 13.1to 16.1 ℃, and the average temperature difference between indoor and outdoor air was 12.8-21.0℃. The average heat flux of the glass roof that was covered with the external thermal blanket was 50.0-97.7 W/m~2, while the single-layer glass roof was 217.6-367.9 W/m~2. The greenhouse covering with the external thermal blanket was reduced by 75% in the heat loss of the glass greenhouse roof. At the same time, the average heat flux was 141.1-232.2 W/m~2 in the Venlo-type one with double-layer indoor thermal screens in use. The roof heat loss of the multi-span greenhouse with the external insulation was reduced by 36%, indicating a better insulation performance. The mean heat energy input of the multi-span greenhouse with external insulation was measured to be 74.5 W/m~2 during the heating period, maintaining an average temperature difference between indoor and outdoor air of 17.4 ℃. Thus, the energy consumption of heating the multi-span greenhouse with the external insulation was low. Finally, the fitted influence of indoor and outdoor air temperature differences on the heat fluxes of greenhouse roofs was presented, and the tested greenhouse showed better goodness of fitting. This finding can provide a new type of greenhouse structure for the low-carbon and energy-saving production of multi-span greenhouses. A data basis can also be offered for the optimal design and engineering application of the multi-span greenhouse with external insulation.

[目的]以对照和内生菌根菌内球囊霉处理的草莓重茬土为培养基质,种植草莓90 d后,分离和鉴定草莓根际土壤真菌.[方法]采用土壤液梯度稀释涂板法分离真菌纯培养,提取真菌DNA,利用真菌ITS序列的同源性,进行分子鉴定.[结果]重茬土中分离出4种有益真菌,12种致病菌种.内球囊霉处理的重茬土中分离得到15种有益真菌,9种致病菌种.[结论]菌根真菌处理后可以显著提高有益真菌的种类,减少致病菌的种类.

Chestnuts are important ecological forest tree species. They can form mycorrhizal connections with a variety of ectotrophic mycorrhizal fungi. Mycorrhizal hyphae can expand the absorbing area to facilitate the intake of nutrients, thereby promoting plant growth and development. In this study, a chestnut-fungus symbiosis system was established in vitro, and typical mycorrhizal structures (root tips bifurcated and apical enlargement) were found after three-month inoculation. Phosphorus content and H+ efflux rate of chestnut roots increased significantly after being inoculated with Scleroderma citrinum compared to the non-inoculated control. The increased H+ efflux rate provides indirect evidence for the role of ectomycorrhizae in increased phosphate uptake. Finally, phylogenetic tree was clustered by MEGA5.0 based on amino acid sequences of five phosphate transporters of Castanea mollissima and known phosphate transporters of other plants. The results showed that CmPT4 was in a Glade with known mycorrhizal phosphate transporters, and thus this gene was preliminarily a predicted mycorrhizal phosphate transporter. Further real-time quantitative PCR showed that five phosphate transporter genes (CmPT1, CmPT2, CmPT3, CmPT4, and CmPT5) were upregulated under phosphorus deficiency treatment, and only CmPT4 was induced in the mycorrhizal roots of chestnut. Therefore, It can be concluded CmPT4 is a mycorrhizal phosphate transporter gene in Castanea mollissima. This study provides a foundation for further analysis of chestnut mycorrhizal formation and phosphate uptake improvement by phosphate transporters. (C) 2016 Elsevier B.V. All rights reserved.

根据9-顺式-环氧类胡萝卜素加双氧酶(NCED)基因序列信息设计引物,通过RT-PCR在燕山红栗(Castanea mollissima cv.‘Yanshanhongli’)中克隆得到了基因NCED1.利用MEGA5.0软件将其氨基酸序列与其他植物的NCED1氨基酸序列进行聚类分析,同时采用实时荧光定量PCR的方法,对燕山红栗坚果不同发育时期的进行基因表达量分析.结果表明:NCED1在燕山红栗坚果发育过程中均有表达,且在坚果发育后期相对表达量达到峰值,推测ABA对燕山红栗坚果的成熟具有调节作用.

To investigate the effects of iron deficiency stress on photosynthetic characteristics and iron contents of organelles in strawberry(Fragaria × ananassa Duch.) seedlings,four strawberry cultivars(Hongyan,Zhangji,Tianchali,Tongzi No.1) were cultured in solution with or without Fe(II)-EDTA(×10-4 mol/L).After 0,4,8,12 and 16 days of treatment,chlorophyll content(SPAD),photosynthetic rate(Pn),chloroplast iron content,and root mitochondrial iron content of strawberry seedlings were determined.The results show that the iron deficiency stress significantly reduces the chlorophyll content,photosynthetic rate,and chloroplast iron content,leaf iron content,root iron content and biomass of strawberry seedlings,and the differences between different cultivars are significant(P0.05).The iron deficiency treatment has little effect on the root mitochondrial iron content.The result of correlation analysis show that there are significantly correlations between the chloroplast iron content and the leaf iron content,photosynthetic rate and biomass of strawberry(r=0.93**,r=0.87** and r=0.72**),and the root mitochondrial iron content is correlative significantly with the root iron content,photosynthetic rate and biomass of strawberry(r=0.83**,r=0.72** and r=0.52*).Under the condition of this experiment,the effect of iron deficiency stress on the strawberry cultivar of Hongyan is larger than those of the other three cultivars.