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[学术文献 ] 日光温室主动蓄放热系统优化 进入全文
农业工程学报
为了提高日光温室主动蓄放热系统运行的稳定性和可靠性,该研究在第六代主动蓄放热系统的基础上,对主动蓄放热系统的循环管路、供水方式和集放热板进行优化改进,并对系统的加温效果和性能进行探究。研究结果表明,在3种不同的太阳辐射强度天气条件下,试验区的平均气温比对照区分别高2.7、2.2和1.9℃;单位面积集热量分别为4.6、3.7和2.6 MJ/m~2,单位面积放热量分别为4.1、3.4和3.1 MJ/m~2;平均集热功率分别为183.1、146.5和105.0 W/m~2,平均放热功率分别为163.2、134.0和121.1W/m~2;平均集热效率分别为56.5%、68.2%和73.8%;平均性能系数分别为3.8、3.1和2.8;与电加热相比,平均节能率分别为73.5%、67.1%和63.0%。在主动蓄放热系统加温期间,在不同太阳辐射强度天气条件下,试验区南北温差较大,植株群体内部南北最大平均气温分别相差2.8、2.6和2.4℃。研究结果可为主动蓄放热系统的推广应用提供理论基础和数据支撑。
[学术文献 ] Tomato transcriptional repressor MYB70 directly regulates ethylene-dependent fruit ripening 进入全文
The Plant Journal
Ethylene is a key plant hormone controlling the ripening of climacteric fruits, and a few transcription factors acting as important regulators of fruit ripening have been identified in tomato (Solanum lycopersicum), a model for climacteric fruits. However, the vast majority of them are transcriptional activators, and the associated transcriptional regulatory mechanisms of most regulators are unclear. Here, we report on a tomato transcriptional repressor (termed SlMYB70) that negatively regulates fruit ripening by directly modulating ethylene biosynthesis. As an EAR motif‐containing MYB transcription factor‐encoding gene, SlMYB70 displayed a ripening‐associated expression pattern and was responsive to ethylene. RNA interference (RNAi)‐mediated repression of SlMYB70 accelerated fruit ripening, but overexpression of SlMYB70 delayed fruit ripening. Ethylene production was noticeably increased and decreased in SlMYB70‐RNAi and SlMYB70‐overexpressing lines, respectively, compared to wild‐type tomatoes. SlMYB70 was proven to be a transcriptional repressor, dependent on the EAR repression motif, and to repress the transcription of two ethylene biosynthesis genes in fruit ripening, namely, SlACS2 and SlACO3. The promoters of SlACS2 and SlACO3 are directly bound by SlMYB70, which was verified by using a combination of yeast one‐hybrid, chromatin immunoprecipitation‐qPCR, and electrophoretic mobility shift assays. These results suggest that SlMYB70 negatively regulates fruit ripening via direct transcriptional repression of ethylene biosynthesis genes, which provides insights into the ethylene‐mediated key regulatory hierarchy in climacteric fruit ripening and also highlights different types of transcriptional regulation of fruit ripening.
[学术文献 ] SlTLFP8 reduces water loss to improve water‐use efficiency by modulating cell size and stomatal density via endoreduplication 进入全文
Plant, Cell & Environment
Improving plant water‐use efficiency (WUE) is important to plant survival and crop yield in the context of water limitation. In this study, SlTLFP8 (Tubby‐like F‐box protein 8) was identified as an osmotic‐induced gene in tomato. Transgenic tomato with up‐regulated expression of SlTLFP8 showed enhanced water‐deficient resistance, while knockout mutants generated by CRISPR/Cas9 were more sensitive to water deficit. SlTLFP8 overexpression significantly enhanced WUE by suppressing transpiration under both water‐sufficient and water‐deficient conditions. Further study showed that overexpressing SlTLFP8 significantly increased leaf epidermal cell size and thereby decreased stomatal density 10%–20%, conversely SlTLFP8 knockout resulted in decreased cell size and thereby increased stomatal density 20%–50%. SlTLFP8 overexpression and knockout modulated ploidy levels in leaf cells. Changes in expression of cell cycle related genes also indicated that SlTLFP8 affected cell size and stomatal density through endocycle transition. Despite changes in stomata density and transpiration, altering the expression of SlTLFP8 did not change photosynthesis. Additionally, biomass was not altered and there was little difference in fruit yield for transgenic and wild type lines under water‐sufficient and water‐deficient conditions. Our results demonstrate the effect of SlTLFP8 on endoreduplication and the potential of SlTLFP8 for improvement of WUE.
[学术文献 ] 瓜类作物离体雌核诱导单倍体研究进展 进入全文
园艺学报
单倍体和双单倍体对于作物改良和遗传分析具有重要意义。在瓜类作物的研究中，通过诱导离体雌核发育是获得单倍体和双单倍体的有效途径。综述了瓜类作物未受精子房和胚珠离体培养的研究概况及影响因素，总结了再生植株鉴定、单倍体加倍和应用方面的进展，分析了目前研究存在的问题以及未来的研究方向，最后对瓜类作物单倍体研究的发展前景做简要地展望，以期为后续瓜类作物离体雌核发育诱导单倍体的研究提供参考。
[学术文献 ] 基于温室环境和作物生长的番茄基质栽培灌溉模型 进入全文
农业工程学报
为解决涵盖土壤蒸发和作物冠层蒸腾的土培作物蒸散模型不能直接应用于稻壳炭基质栽培番茄灌溉的问题，该研究首先通过修改Penman-Monteith模型的原始表达式来去除土壤蒸发部分，并引入TOMGRO模型来模拟番茄冠层生长，给出了阻抗参数的修正计算，得到了新的番茄基质栽培蒸腾模型。考虑到蒸腾模型中净辐射项削弱了室外太阳辐射对冠层及以下部整株植株的耗水影响，进而将新的蒸腾模型与太阳辐射线性比例供水模型结合建立蒸腾－辐射综合灌溉模型。结果表明，蒸腾－辐射综合灌溉模型对上海崇明A8温室番茄灌溉量的模拟结果与实际结果之间的相关系数高于0.95，平均相对误差小于20%。这说明蒸腾－辐射综合灌溉模型能够较好地估算温室稻壳炭基质栽培番茄的灌溉需水量，对深入研究温室灌溉实施具有参考价值。
[学术文献 ] 番茄果实颜色形成的分子机制及调控研究进展 进入全文
园艺学报
番茄果实颜色主要包括绿色、黄色、红色、粉色和紫色等，这些颜色的形成是叶绿素、类胡萝卜素、番茄红素、黄酮类化合物等多种次生代谢物质积累综合呈现的结果。针对近年来关于控制番茄果实颜色形成的相关基因、生物合成途径及其调控机制的研究进展进行了综述，旨在为今后通过生物 技术手段进行番茄果色农艺性状改良提供参考。
