为了探讨紫茎泽兰种子需光萌发特性,对光质(不同颜色、红光/远红光)和光强对种子萌发率及幼苗状态进行了研究。研究发现:不同颜色光对发芽率影响显著,其中黄光、橙光和红光等波长在(591—750nm)之间的光更有利于提高种子的萌发率(74.3%-83.3%),而较短波长的光(〈570nm,紫光、蓝光和绿光)促进效果显著降低(62.3%~66.7%)(P〈0.05)。光强对紫茎泽兰种子发芽和幼苗影响较光的颜色更具有规律性。黑暗条件下发芽率22%,随着光照提高,发芽率指数增加(r2=0.96),芽长指数下降(r2=0.99)、根长指数增加(r2=0.98),而鲜重呈现线性增加(r2=0.70)。适量红光(630nm)和远红光(730nm)照射能够打破和引起休眠,红光照射量与发芽率提高量成线性正相关(r2=0.98),而远红光照射率与发芽率降低量呈线性正相关(r2=0.92),说明紫茎泽兰需光萌发是一个光敏色素引起的过程。紫茎泽兰通常在裸地和人为干扰土壤上泛滥,这可能与其种子需光萌发有关。而对其生态学控制可以考虑从光强、特别是光质角度(如人工造林)控制种子萌发来实现。
For understanding the features of light-demanding seed germination of Eupatorium adenophorum, the influences of light qualities (different colors, red/far-infrared light) and light intensity on seedling sprouting of this weed were studied in this paper. Lights of different colors have significantly influence on the parameters of seedling sprouting, i. e. , yellow light, orange light and red light, which have longer wavelength, were more suitable for facilitating seed germination rate (74.3% -83.3% ), while the shorter wavelength lights ( 〈 570 nm, violet, blue and green lights) had significant lower seed germination rates ( 62.3 % - 66.7 % ) (p 〈 0.05 ). Light intensity had markedly more regularity on seed germination and seedling status than the color of the light. Under the condition of darkness, germination rate was 22%. Along with the light enhancement both in transmittance and lux, exponential increases in seed germination ( r2 = 0.96) and root length 〈 r2 = 0. 98 ) were observed, while height of seedlings exponentially decreased ( r2= 0.99) ; a linear increase in fresh mass was simultaneously observed ( r2 = 0.70). Appropriate radiation of red light ( 630 nm) and far-infrared light (730 nm) can break and cause dormancy. The exposure amount of red light linearly related with germination increase with reference to dark control ( r2 = 0.98 ) , while the amount of far-infrared light was linearly correlated with zermination decrease with reference to control ( r2 = 0.92 ). This indicates that light-demanding seed germination of E. adeno'phorum is a phytochromes-induced process. E. adenophorum generally runs rampant in barren and disturbed lands and light sensitive germination should be partially responsible for that. The ecological control of this weed should consider light regulation, in particular the light quality ( such as afforestation decreases red light/ far-infrared ratio) to decrease seed germination.