盐胁迫对酿酒葡萄叶片细胞结构及光合特性的影响

【目的】研究100 mmol•L-1 NaCl胁迫下，葡萄酿酒品种‘赤霞珠’、砧木‘5BB’ 和砧穗组合苗‘赤霞珠/5BB’叶片细胞解剖结构和光合特性，为葡萄品种、砧木及砧穗组合苗耐盐性的筛选提供理论依据和技术方案。【方法】采用盆栽方法，当葡萄苗生长到高度约60 cm时，用100 mmol•L-1 NaCl 处理30 d，随后测定叶片的叶绿素含量、光合作用参数及叶绿素荧光参数等指标，并用显微和透射电镜观察其细胞结构特征。【结果】100 mmol•L-1NaCl胁迫下，葡萄叶片表皮细胞、栅栏组织和海绵组织厚度增加，栅栏组织/海绵组织比降低；叶绿体长宽分别扩大1.3-1.5倍和1.3-2.0倍，类囊体肿胀变大；叶绿素含量降低，特别是叶绿素b（Chl b）下降明显；叶片光系统Ⅱ（PSII）潜在活性（Fv/Fo）、原初光能转换效率（Fv/Fm）和叶片净光合速率（Pn）均显著降低。3种类型苗木对NaCl胁迫的反应不同，100 mmol•L-1 NaCl对砧木‘5BB’叶片细胞和叶绿体的结构、叶绿素含量和光合速率的影响程度最小，其次为砧穗组合苗‘赤霞珠/5BB’，而对品种‘赤霞珠’的影响最大。【结论】100 mmol•L-1 NaCl胁迫下，葡萄叶片厚度增加，叶绿素含量降低，最终导致PSII潜在活性中心受损，光能转化效率和净光合速率明显降低。葡萄砧木‘5BB’有较强的耐盐能力，可一定程度提高酿酒葡萄‘赤霞珠’的耐盐能力。

Effects of Salt Stress on Mesophyll Cell Structures and Photosynthetic Characteristics in Leaves of Wine Grape (Vitis spp.)

【Objective】The changes of cell structures and photosynthetic characteristics in leaves of three grapes, cultivars ‘Cabernet Sauvignon’(Vitis vinifera L.), rootstock ‘5BB’ (Vitis berlandieri × Vitis riparia), and scion/rootstock combinations ‘Cabernet Sauvignon/5BB’, were investigated under salt stress conditions to offer a theoretical basis and technique reference for selecting salt-tolerant genes in grapevine cultivars, rootstocks and scion/rootstock combinations.【Method】In a pot culture experiment, grapevine plants were treated with NaCl at 0 and 100 mmol•L-1 for 30 d. When the height of grapevines was about 60 cm, chlorophyll contents, gas exchange and chlorophyll fluorescence parameters, and cell structure characteristics in leaves were determined by using spectrophotometer, chlorophyll fluorometer, and observed with microscope and transmission electron microscopy.【Results】Compared with the control, the thickness of epidermis cells, palisade tissue and spongy tissue in leaves of grapevine increased, and thickness ratio of the palisade/spongy tissue reduced under salt stress(100 mmol.L-1 NaCl). Thylakoids became swollen, the length and width of chloroplast increased by 130%-150% and 130%-200%, respectively. Meanwhile, chlorophyll (especially Chl b) content, PSII potential activity(Fv/Fo), maximal photochemistry efficiency of PSII (Fv/Fm) and net photosynthetic rate(Pn) dramatically decreased in leaves of grapevines under salt stress(100 mmol•L-1 NaCl). There was a difference in effect on three grapevines by salt stress. Among them, ‘5BB’ showed a lesser negative effect on cell and chloroplast structures, photosynthetic rate, and PSII photochemical reaction. ‘Cabernet Sauvignon’ in the middle and ‘Cabernet Sauvignon/5BB’ was the largest.【Conclusion】The alterations of mesophyll cell structure and chlorophyll content under salt stress(100 mmol•L-1 NaCl) could led to the deduction of photosynthetic electron transfer efficiency and photosynthetic rate. Rootstock ‘5BB’ exhibited higher salt-tolerance characters which may be beneficial to improve the salt-tolerance of ‘Cabernet Sauvignon’ by grafting on the ‘5BB’.