不同氮素水平辣椒幼苗对低温响应的差异

Differential response of pepper seedlings in different N concentrations to low temperatures

为研究低温对不同氮素水平辣椒幼苗生长的影响,在2228℃条件下分别用0.00g·L-1,2.00g·L-1和3.00g·L-13个浓度尿素水溶液培养的3个品种辣椒4叶1心期幼苗在人工气候箱内进行低温处理。结果显示:3个辣椒品种幼苗对相同低温的响应存在差异,其受低温危害由轻到重依次为中椒四号、市祥206和红龙。3个氮素水平下培养的3个品种辣椒幼苗进行连续3d11.0/5.0℃(Ⅲ)低温处理后,均危害严重,各项生理指标与对照差异显著,不能恢复正常生长,危害的程度因品种和氮素水平高低存在差异,氮素水平愈低受害愈重。连续3d15.0/9.0℃(Ⅰ)或13/7℃(Ⅱ)对辣椒幼苗处理后,受危害的程度仍因品种和氮素水平高低存在明显差异,但各项生理指标与对照差异显著减小,均能恢复生长,且氮素水平愈高,与对照的差异愈小。氮素水平影响辣椒幼苗对低温的响应,浓度较高时(3.00g·L-1)辣椒幼苗抵御低温的能力较强,较高的氮素水平虽能减轻低温对辣椒幼苗的影响程度,却不能完全抵消低温的危害。

Response of pepper （ Capsicum annum） seedlings growing at different N concentrations to varying low temperature was investigated. The seedlings of three pepper varieties grown in pot-culture at three N concentrations including 0. 00,2. 00,and 3. 00g·L^-1urea at 22. 0 28. 0℃ were transferred to climate chambers （12h light/12 h dark with light intensity of 350 μ mol.m^-.2s^-1） respectively. These seedlings were grown with 3 low temperature grades in chambers until the 4 leaves with one bud stage. Subsequently,there were significant difference in damage responded low temperature among three pepper varieties seedlings,which were grown at a same low temperature grade. Honglong showed the highest damage degree,followed by Shiqiang 206,and Zhongjiao No. 4. In particular,the pepper seedlings at varying N levels were injured severely after 3 days at low temperature stress of 11. 0 /5. 0℃. Significant differences in all of physiological index tested were observed between treatment and control seedlings. It appeared from the results that damage degree of the seedlings under low temperature stress varied with varieties and N concentrations. The lower N concentration was,the more severely injured. However,after 3 days at low temperature stress of 15. 0 /9. 0℃ （Ⅰ） or 13 /7℃ （Ⅱ）the pepper seedlings injured differently depending on varieties and N concentrations as well,differences with CK of all tested physiological index were reduced significantly,and could recover at 22. 0 28. 0℃ for the following 6 days,the higher N concentration,the better recovered. It could be concluded that N concentrations impacted the responses of pepper seedlings to low temperature. The higher concentration （3. 00g·L^-1 urea） should enhanced pepper seedlings anti-low-temperature ability. Though the higher N concentration could mitigate the low temperature injuries on pepper seedlings,it couldn＇t entirely offset the low temperature effects.