西瓜短侧枝突变体slb光合特性研究

Photosynthetic characteristics of short lateral branching mutant slb of watermelon

【目的】探究西瓜短侧枝突变体slb的光合特性,为西瓜短侧枝突变体的利用奠定基础。【方法】以西瓜短侧枝突变体slb和正常长侧枝品系GWAS-38为材料,测定坐果期第10~15节功能叶的光合色素(叶绿素a、叶绿素b、总叶绿素和类胡萝卜素)含量、光合参数(净光合速率(P_(n))、气孔导度(G_(s))、胞间CO_(2)浓度(C_(i))、蒸腾速率(T_(r)))、荧光动力学参数(初始荧光(F_(0))、最大荧光(F_(m))、最大光化学效率(F_(v)/F_(m))、实际光化学效率(F_(v)′/F_(m)′)、实际光化学量子效率(Φ_(PSⅡ))、光化学淬灭系数(qP)和电子传递效率(ETR))以及气孔的密度、长度和开度。【结果】与正常长侧枝GWAS-38相比,西瓜短侧枝突变体slb功能叶的叶绿素a、叶绿素b和总叶绿素含量以及叶绿素a/叶绿素b、类胡萝卜素/总叶绿素均无显著变化,但类胡萝卜素含量显著降低了9.52%。短侧枝突变体slb功能叶的P_(n)、G_(s)、C_(i)和T r分别较正常长侧枝GWAS-38极显著降低了46.0%,75.0%,18.8%和47.0%。与正常长侧枝GWAS-38相比,短侧枝突变体slb功能叶的F_(0)极显著升高了17.9%,而F_(m)、F_(v)/F_(m)、F_(v)′/F_(m)′、Φ_(PSⅡ)、qP和ETR均无显著差异;气孔密度极显著增加了140.2%,而气孔长度和开度分别极显著下降了32.1%,40.4%。【结论】气孔限制是导致西瓜短侧枝突变体slb光合作用下降的主要因素。

【Objective】This study investigated the photosynthetic properties of short lateral branching mutant slb of watermelon to provide basis for its application.【Method】Using short lateral branching mutant slb and normal long lateral branching line GWAS-38 as materials,the photosynthetic pigment contents(chlorophyll a(Chl a),chlorophyll b(Chl b),total chlorophyll(Chl)and carotenoids(Caro)),photosynthetic parameters(net photosynthetic rate(P_(n)),stomatal conductance(G_(s)),intercellular CO_(2) concentration(C_(i))and transpiration rate(T_(r))),fluorescence kinetic parameters(minimal fluorescence(F_(0)),maximal fluorescence(F_(m)),maximal quantum yield(F_(v)/F_(m)),actual photochemical efficiency(F_(v)′/F_(m)′),actual photochemical quantum efficiency(Φ_(PSII)),photochemical quenching coefficient(qP)and electron transfer efficiency(ETR)),as well as stomatal density,length and aperture of functional leaves at 10-15 nodes were determined during fruit setting stage.【Result】Compared with GWAS-38,there was no significant difference in chlorophyll a(Chl a),chlorophyll b(Chl b),total chlorophyll(Chl),chlorophyll a/chlorophyll b(Chl a/Chl b)and carotenoid/total chlorophyll content(caro/Chl)of functional leaves of the short lateral branching mutant slb,but the carotenoid content decreased significantly by 9.52%.The P_(n),G_(s),C_(i) and T r of functional leaves of mutant slb were significantly decreased by 46.0%,75.0%,18.8%and 47.0%in comparison to GWAS-38.Compared with GWAS-38,F_(0) of mutant slb functional leaves was very significantly increased by 17.9%,while F_(m),F_(v)/F_(m),F_(v)′/F_(m)′,Φ_(PSⅡ),qP and ETR showed no significant differences.The stomatal density was increased by 140.2%,while the stomatal length and aperture were decreased by 32.1%and 40.4%,respectively.【Conclusion】Stomatal limitation was the main factor resulting in the decrease of photosynthesis of the short lateral branching mutant slb.