对干旱胁迫0～15 d露地菊（Chrysanthemum morifolium Ramat.）品种‘纽9717’（‘Niu 9717’）野生型和3个转ClNAC9基因株系（ClNAC9-5、ClNAC9-6和ClNAC9-13株系）叶片的叶绿素含量、光合参数和叶绿素荧光参数进行了比较和分析。结果表明：干旱胁迫0～15 d，野生型和3个转ClNAC9基因株系叶片中叶绿素含量总体上呈先升高后降低的变化趋势。与干旱胁迫0 d相比较，除初始荧光（F_o）和非光化学淬灭系数（qN）外，干旱胁迫15 d时3个转ClNAC9基因株系叶片的叶绿素含量、净光合速率（Pn）、气孔导度（Gs）、蒸腾速率（Tr）、水分利用效率（WUE）、最大荧光（F_m）、可变荧光（F_v）、PSⅡ最大光化学效率（F_v／F_m）、PSⅡ潜在光化学活性（F_v／F_o）和光化学淬灭系数（qP）的降幅均小于野生型。总体上看，干旱胁迫15 d，3个转ClNAC9基因株系叶片的叶绿素含量、Pn、Gs、Tr、WUE、F_m、F_v、F_v／F_m、F_v／F_o、qP和qN值显著高于野生型，而F_o值显著低于野生型。研究结果显示：将ClNAC9基因转入露地菊品种‘纽9717’可以增强该品种对干旱胁迫的耐受性，其中，ClNAC9-5和ClNAC9-6株系对干旱胁迫的耐受性较强，ClNAC9-13株系对干旱胁迫的耐受性较弱，但均强于野生型。

Chlorophyll content， photosynthetic parameters， and chlorophyll fluorescence parameters of leaves of wild type and three transgenic lines with ClNAC9 gene （line ClNAC9-5， ClNAC9-6， and ClNAC9-13） of cultivar ‘Niu 9717’ of groundgrow chrysanthemum （Chrysanthemum morifolium Ramat.） under drought stress for 0-15 d were compared and analyzed. The results show that under drought stress for 0-15 d， chlorophyll content in leaves of wild type and three transgenic lines with ClNAC9 gene shows a tendency to first increase and then decrease in general. Compared with drought stress for 0 d, except initial fluorescence （F_o） and nonphotochemical quenching coefficient （qN）， the decreasing ranges of chlorophyll content, net photosynthetic rate （Pn）， stomatal conductance （Gs）， transpiration rate （Tr）， water use efficiency （WUE）， the maximum fluorescence （F_m）， variable fluorescence （F_v）， the maximum photochemical efficiency of PSⅡ （F_v／F_m）， potential photochemical activity of PSⅡ （F_v／F_o）， and photochemical quenching coefficient （qP） of leaves of three transgenic lines with ClNAC9 gene under drought stress for 15 d are all smaller than those of leaves of wild type. In general， under drought stress for 15 d， chlorophyll content, Pn， Gs， Tr， WUE， F_m， F_v， F_v／F_m， F_v／F_o， qP， and qN values of leaves of three transgenic lines with ClNAC9 gene are significantly higher than those of leaves of wild type， while their Fo value is significantly lower than that of leaves of wild type. It is suggested that introduction of ClNAC9 gene into cultivar ‘Niu 9717’ of ground-grow chrysanthemum can enhance tolerance of this cultivar to drought stress， in which， drought stress tolerance of line ClNAC9-5 and ClNAC9-6 is relatively strong， while that of line ClNAC9-13 is relatively weak， but all of them are stronger than that of wild type.