海拔高度对暗紫贝母叶特征的影响

Effects of altitude on leaf traits of Fritillaria unibracteata

关键词:  暗紫贝母, 叶寿命, 气孔密度, 气孔长度, 比叶面积, 高山生态

Key words:  Fritillaria unibracteata, leaf lifespan, stomatal density, stomatal length, specific leaf area, alpine ecology

摘要:

为探索海拔高度对暗紫贝母(Fritillaria unibracteata)叶特征的影响,该研究在岷江上游的卡卡山北坡设置低、中、高三个海拔部位,并在高、低部位之间进行植株的移栽试验,并测定每个部位植株的叶寿命、气孔密度和长度、单叶面积及比叶面积等叶特征。结果表明:(1)叶寿命从低海拔部位的121.3 d,到高海拔部位的108.5 d,缩减了大约13 d。(2)从低海拔到高海拔,气孔密度逐渐升高,低海拔部位只有48.5 number·mm^-2,高海拔部位与之相比增加了42.8%。(3)而气孔长度则随海拔升高而降低,从低海拔部位的82.4 μm 到高海拔的71.3 μm,降低了13.5%。(4)从低海拔到高海拔,单叶面积和比叶面积都逐渐增加,其中单叶面积由低海拔部位的1.61×10^-4 m²到高海拔部位的2.20×10^-4 m²,增加了36.6%; 比叶面积则由低海拔部位的7.7×10^-4 m²·kg^-1到高海拔部位的12.5×10^-4 m²·kg^-1,增加了62.3%。(5)另外,同一海拔部位的对照植株和移栽植株之间叶特征并无显著差异; 植株在移栽后总是表现出移栽后所在部位对照植株的特点,而没有表现出移栽前所在部位对照植株的特点。综上结果表明,海拔高度对暗紫贝母叶特征影响显著,暗紫贝母的叶特征在海拔梯度上具有较大的可塑性。

Abstract:

As an important traditional Chinese medicinal plant, Fritillaria unibracteata is mainly distributed in alpine areas with an elevation above 3 000 m. Unsustainable harvesting of this species has greatly destroyed its natural habitats and made it more valuable. Among all factors affecting its growth, altitude is the most obvious one. To explore the effects of altitude on leaf traits of F. unibracteata, three altitudinal sites(low site, medium site and high site)were set up on the north-facing slope of Kaka Mountain in the upper reaches of Min River, and plant transplant experiments were carried out between low site and high site, which was 108.5 d. Then leaf traits including leaf lifespan, stomatal density and length, single leaf area and specific leaf area in each site were measured. In these experiments, some meaningful results were produced. The results were as follows:(1)From low site to high site, leaf lifespan shortened, and there were significant differences among sites. Leaf lifespan at low site was 121.3 d, about 13 d was shortened more than that at high site, which was 108.5 d. Along with altitude rise, stomatal density increased.(2)Compared with low site with only 48.5 stomas per square milimeter, stomatal density in high site increased by 42.8%.(3)Contrary to stomatal density, stomatal length decreased along with the increase of altitude. Compared with low site with 82.4 μm, stomatal length at high site with 71.3 μm reduced by 13.5%.(4)As to single leaf area and specific leaf area, they both showed a rising trend from low site to high site. At low site with 1.61×10^-4 m², single leaf area at high site reached 2.20×10^-4 m², 36.6% more than that at low site; similarly, specific leaf area at high site was 12.5×10^-4 m²·kg^-1, 62.3% higher than that at low site with 7.7×10^-4 m²·kg^-1. At the same altitudinal site, the control plants and transplants did not differ significantly.(5)For those transplanted plants, they always performed in accordance with control plants at the same altitudinal site after transplant experiment, but did not show characters of control plants at different altitudinal sites before transplant experiment. It can be concluded that altitude exerts an evident influence on leaf traits of F. unibracteata, and that leaf traits of F. unibracteata is of great plasticity when environment conditions change.