作 者 ：马生军,谭敦炎
期 刊 ：生态学报 2007年 27卷 2期 页码：486~496
关键词：准噶尔荒漠；短命植物；十字花科；物候；开花式样；性表达；交配方式；生态适应；
Keywords:Junggar desert, ephemeral plants, Brassicaceae, phenology, floral display, sex expression, mating pattern, ecological adaptation,
摘 要 ：甘新念珠芥（Neotorularia korolkovii）和宽翅菘蓝（Isatis violascens）是两种广泛分布于新疆准噶尔荒漠的十字花科早春短命植物。对其物候与性表达特征研究结果表明：(1) 二者种子均在3月下旬萌发，5月下旬和6月上旬果实完全成熟，生活周期分别为62d和71d，其中营养生长期约占1/3、生殖生长期约占2/3。(2) 花均为两性，四强雄蕊，单花开放时间较短，长雄蕊的花药开裂早于短雄蕊，但短雄蕊花药中的花粉数较长雄蕊的多。(3) 长、短雄蕊花药中花粉可育率均达90%以上，花粉活力的变化曲线基本相同，柱头可授期分别为9.0h和4.5h，花粉寿命及柱头可授期均短于单花花期，花粉活力最高的时期正是其柱头的最佳授粉期。柱头可授期与花粉活力及寿命在时间上的高度吻合，增加了在不可预测环境中授粉的机会与效率，从而保障生殖成功。(4) 二者的P/O（花粉/胚珠）值分别为108.07±17.17、992.10±272.16，属于自交繁育系统；对其传粉过程、套袋实验及荧光显微观察的结果也证明它们主要以自花传粉的方式来进行交配。(5) 两种植物从物候、花部性表达以及交配式样上均存在与其严酷荒漠环境相适应的特点，是长期适应准噶尔荒漠特殊生态环境的结果，对于保证繁殖成功并扩大种群具有重要的意义。
Abstract:Neotorularia korolkovii and Isatis violascens (Brassicaceae) are early-spring ephemerals common in the Junggar Basin, Xinjiang. Phenology and sex expression of the two species are as follows. (1) Seed germination occurs in late March, fruits are fully mature in late May and early June, and lengths of the life cycles were 62d and 71d, respectively. In both species, vegetative growth accounted for one-third of the length of the life cycle and reproductive growth for two-thirds. (2) Flowers of both species are bisexual and tetradynamous. Difference in anther length of long and short stamen in N. korolkovii was not significant (p>0.05), but filament length between long and short stamen was significant (p<0.01). In I. violascens, differences in length of anther and filament between long and short stamen were significant (p<0.01). (3) Anthesis of individual flowers in the two species lasted 1-2d. The anther of the long stamen dehisced about 20min to 1.0h before the flower opened, while the anther of short stamen dehisced at anthesis. (4) Fertility rates of pollen were >90% in both species, but on a anther basis short stamen had more pollen grains than the long stamen.(5) Survivorship(viability) curves for pollen in long and short stamen were similar, and pollen viability was high at the beginning of anther dehiscence in both species. In N. korolkovii, pollen viability of long and short stamen at the beginning of anther dehiscence was 98% and 97%, respectively. Maximums lengths of pollen longevity for N. korolkovii was about 33.0h, and the optimal pollination phase was 09.0h after the shedding of pollen. However, in I. violascens pollen viability of long and short stamen was 99% and 98%, respectively, and their pollen longevity was about 7.0h. The optimal pollination phase for the species was 03.0h after the shedding of pollen. In N. korolkovii and I. violascens, optimal stigma receptivity was 03.0h and 02.0h after anthesis respectively. The period of anther dehiscence was highly correlated with the period of high pollen viability and with the period of high stigma receptivity. (6) P/O ratios of N. korolkovii and I. violascens were 108.07±17.17 and 992.10±272.16, respectively. There were no pollinators visitations during the flowering phase of either species, and self-pollen of both species was easily transferred by gravity to the stigma, where it germinated readily. Fruit-set in flowers of N. korolkovii and I. violascens without emasculation and with bagging was 80.00% and 79.43%, respectively, and fruit-set in naturally-pollinated plants was 84.26% and 82.51%, respectively. Based on these results, the breeding system of the both species is predominantly selfing. (7) Thus we can conclude that both species have special adaptive strategies in phenology, floral sex expression and mating pattern to the unpredictable Junggar desert environment and that these traits increase fitness of the populations.