ADAPTIVE SIGNIFICANCE OF SAUSSUREA PARVIFLORA'S SEXUAL ORGANS, QINGHAI-TIBETAN PLATEAU, CHINA

doi:10.3773/j.issn.1005-264x.2008.02.015

Abstract

Abstract:

Aims Saussurea parviflora is the dominant species on the Qinghai-Tibetan Plateau. This study addresses the following: 1) correlations between S. parviflora's sexual organs and altitude, 2) correlations among S. parviflora's sexual organs, and 3) reasons for S. parviflora's adaptation to this stressful environment.
Methods During the flowering phase in August-September 2005, we collected 11 populations of S. parviflora from different altitudes. We harvested 20 individuals from each population and randomly selected 10 capitula from each individual. We randomly selected 20 flowerlets from different capitula from the same altitude and fixed them in FAA (18:2:2, alcohol:formaldehyde:glacial acetic acid). We measured the length of sexual organs in 20 fully-opened flowerlets and counted pollen in 10 mature flowerlets with undehisced anthers. At the fruiting stage in October 2005 and 2006, we harvested 10 individuals of each population and randomly selected 200 capitula to count the maturation rate. All experimental data were analyzed with the statistical analysis software SPSS11.5.
Important findings There was a strong positive correlation among filament length, anther length and altitude (p<0.01) and a strong negative correlation between pollen number and altitude (p<0.01). Moreover, there were strong positive correlations among 1) style length, length of style ramification and altitude (p<0.01) and 2) style length, length of style ramification, filament length and anther number (p<0.05), and between maturation rate and altitude (p<0.05). Therefore, variation of intraspecific sexual organs under specific environmental condition made S. parviflora adapted to the Qinghai-Tibetan Plateau. With reduced pollen number and insect diversity, abundance and activity with increased altitude, the style ramification lengthened and maturation rate improved. This enhanced the sensitivity to pollinators, ensuring that the decreased pollen was sufficiently spread by them, resulting in increased success of reproduction and dominance in the stressful environment.

Key words: Saussurea parviflora, sexual organ, altitude variation, Qinghai-Tibetan Plateau

WANG Yi-Feng, GAO Hong-Yan, SHI Hai-Yan, WANG Jian-Hong, DU Guo-Zhen. ADAPTIVE SIGNIFICANCE OF SAUSSUREA PARVIFLORA'S SEXUAL ORGANS, QINGHAI-TIBETAN PLATEAU, CHINA[J]. Chin J Plant Ecol, 2008, 32(2): 379-384.

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Figures/Tables 11

Table 1 The samples of Saussurea parviflora

居群 Population	取样数 Sample number	海拔(m) Altitude	经度 Longitude (N)	纬度 Latitude (E)	地点 Location	日期 Date
1	20	2 100	103°52'	34°27'	清水 Qingshui	2005.9.6
2	20	2 600	103°18'	34°42'	临潭 Lintan	2005.9.13
3	20	2 700	102°49'	34°52'	扎油沟 Zhayougou	2005.9.29
4	20	2 800	103°4'	34°43'	下巴沟 Xiabagou	2005.8.13
5	20	2 850	103°4'	34°43'	下巴沟 Xiabagou	2005.8.13
6	20	2 900	103°0'	34°32'	车巴沟 Chebagou	2005.9.9
7	20	2 980	103°6'	34°51'	沙冒寺 Shamaosi	2005.9.2
8	20	3 100	102°25'	35°12'	夏河 Xiahe	2005.9.26
9	20	3 300	102°19'	35°8'	桑科 Sangke	2005.9.3
10	20	3 420	101°7'	34°15'	欧拉秀玛 Oulaxiuma	2005.9.21
11	20	3 500	101°33'	34°13'	可卿 Keqing	2005.9.19

Fig.1 Linear regression between the altitude (x) and the filament length (y)

Fig.2 Linear regression between the altitude (x) and the anther length (y)

Fig.3 Linear regression between the altitude (x) and the pollen number (y)

Fig.4 Linear regression between the altitude (x) and the style length (y)

Fig.5 Linear regression between the altitude (x) and the length of style ramification (y)

Fig.6 Linear regression between the filament length (x) and the pollen number (y)

Fig.7 Linear regression between the style length (x) and the pollen number (y)

Fig.8 Linear regression between the length of style ramification (x) and the pollen number (y)

Fig.9 Linear regression between the altitude (x) and the ratio of length of style ramification and the pistil length (y)

Fig.10 Linear regression between the altitude (x) and the maturation rate (y)

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