中国农业科学 ›› 2018, Vol. 51 ›› Issue (13): 2561-2569.doi: 10.3864/j.issn.0578-1752.2018.13.011

• 园艺 • 上一篇    下一篇

甜瓜叶片光合产物输出能力对弱光的响应

杨柳燕,陈菁菁,陈年来   

  1. 甘肃农业大学园艺学院,兰州 730070
  • 收稿日期:2017-12-14 出版日期:2018-07-01 发布日期:2018-07-01
  • 通讯作者: 陈年来,E-mail:chennl@gsau.edu.cn
  • 作者简介:杨柳燕,E-mail:zyyangliuyan@163.com
  • 基金资助:
    甘肃省农业生物技术研究与应用开发项目(GNSW-2015-17)

Responses of Leaf Assimilate Export To Lowlight Stress in Melon

YANG LiuYan, CHEN JingJing, CHEN NianLai   

  1. College of Horticulture, Gansu Agricultural University, Lanzhou 730070
  • Received:2017-12-14 Online:2018-07-01 Published:2018-07-01

摘要: 【目的】研究甜瓜果实发育期坐果节位叶片光合能力、蔗糖合成能力和水苏糖装载能力对遮光的响应,分析不同耐弱光性甜瓜品种同化物输出能力的差异,为进一步研究甜瓜耐弱光品种果实糖分卸载与积累机理奠定基础。【方法】以耐弱光甜瓜品种‘玉金香’和不耐弱光品种‘钰雪三号’为试材,在日光温室条件下于授粉后进行遮光处理,每5 d取样一次,取坐果节位叶片测定叶绿素含量、气体交换参数、葡萄糖、果糖、蔗糖、肌醇半乳糖苷、棉子糖、水苏糖和淀粉含量,同时测定叶片蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)、中性转化酶(NI)、酸性转化酶(AI)、肌醇半乳糖苷合成酶(GS)和水苏糖合成酶(STS)活性。【结果】遮光处理后,两个甜瓜品种叶片叶绿素a/b、净光合速率(Pn)、葡萄糖、果糖和蔗糖含量均显著降低,淀粉含量升高,‘玉金香’叶绿素a/b降幅(10.0%)大于‘钰雪三号’(5.8%),而Pn、蔗糖含量降幅(分别为30.3%和30.9%)和淀粉含量增幅(3.6%)均显著小于‘钰雪三号’(分别为45.2%、60.6%和20.4%)。遮阴条件下,两个品种叶片蔗糖代谢相关酶SPS、SS、AI和NI活性均显著降低,‘玉金香’SPS和SS酶活降幅(分别为16.5%和30.0%)显著小于‘钰雪三号’(31.6%和40.5%),而AI和NI降幅(分别为23.8%和12.7%)高于‘钰雪三号’。遮光后甜瓜叶片肌醇半乳糖苷含量和GS活性均显著降低,但品种间差异不显著。棉子糖、水苏糖和STS活性均显著降低,‘玉金香’棉子糖含量降幅(65.3%)显著高于‘钰雪三号’(35.0%),而水苏糖和STS活性降幅(分别为79.5%和23.8%)小于‘钰雪三号’。【结论】遮光条件下,耐弱光品种‘玉金香’叶片蔗糖合成能力和水苏糖装载能力下降较少,具有较强的同化物输出能力。

关键词: 甜瓜, 遮阴光理, 气体交换特性, 蔗糖合成, 水苏糖装载, 同化物输出

Abstract: 【Objective】The objective of this study is to evaluate the responses of melon leaf photosynthesis, sucrose synthesis and stachyose loading to low light stress during fruit development stage, and the difference in assimilate export between lowlight tolerance and sensitive cultivars, to support the further analysis of sugar unloading and accumulation in fruits of the lowlight tolerant cultivars. 【Method】 A low light-tolerant cultivar (Yujinxiang) and a low light-sensitive cultivar (Yuxuesanhao) of melon (Cucumis melo L.) were used as materials. The melon plants were cultured in greenhouse and were shaded after pollination. And then the mature leaves from the fruit nodes were collected every five days for measurement. The leaf chlorophyll content, gas exchange parameters, levels of soluble sugars (fructose, glucose, sucrose, galactinol, raffinose, stachyose) and starch, activities of sucrose phosphate synthase (SPS), sucrose synthase (SS), acid invertase (AI), neutral invertase (NI), galactinol synthase (GS) and stachyose synthase (STS) were determined. 【Result】 Under shading condition, leaf chlorophyll a/b, net photosynthetic rate (Pn), and contents of glucose, fructose and sucrose in the leaves of both cultivars decreased, but the starch level increased. The reduction of chlorophyll a/b in Yujinxiang leaves (10.0%) was larger than that in Yuxuesanhao leaves (5.8%), but the reduction of leaf Pn, sucrose content and increment of starch content were less in Yujinxiang (30.3%, 30.9% and 3.6%, respectively) than those of Yuxuesanhao (45.2%, 60.6% and 20.4%). Activities of sucrose metabolism enzymes (SPS, SS, AI and NI) decreased after shading, and the reduction of SPS and SS activities were significantly less in Yujinxiang (16.5% and 30.0%) than in Yuxuesanhao (31.6% and 40.5%), but the reduction of AI and NI activities was larger in Yujinxiang (23.8% and 12.7%) than in Yuxuesanhao (18.3% and 1.8%). Galactinol level and GS activity decreased after shading, but no significant genotypic difference was observed. Contents of raffinose and stachyose as well as the activity of STS all decreased after shading. The reduction of raffinose content was larger, the reduction of stachyose content and STS activity was less in Yujinxiang (65.3%, 79.5% and 23.8%, respectively) than those in Yuxuesanhao (35.0%, 83.3% and 32.4%). 【Conclusion】The reduction of leaf sucrose synthesis and stachyose loading after shading was less in Yujinxiang than in Yuxuesanhao, which indicates that the low light tolerant cultivar has stronger leaf assimilate export capacity than the sensitive cultivar under shading. 

Key words: melon, shading, gas exchange parameters, sucrose synthesis, stachyose loading, assimilates export