盐胁迫下施氮对海滨锦葵营养生长期生长的影响

海滨锦葵Kosteletzkya virginica是耐海水浇灌的经济盐生植物。为优化海滨锦葵在沿海滩涂的栽培，探讨了盐胁迫下施氮对海滨锦葵营养期生物量特征及其关联的影响。实验设为50，150，250mmol·L-1氯化钠及50．150．250mm01·L-1氯化钠＋15mm01·L-1硝酸铵等6个处理。试验采用3-4叶期的海滨锦葵小苗，5个重复·处理-1。研究结果表明：处理35d后，施氮显著增加了植株的高度，当处理为50mmol·L-1氯化钠＋15mmol·L-1硝酸铵时．植株高度为26．1cm．是不施氮处理的1．4倍。施氮对主根长度没有明显影响。低盐下（50mmol·L-1氯化钠）施氮明显增加主根直径．是不施氮的1．4倍。施氮显著（P〈O．05）增加了叶质量比，高盐（250mmol·L-1氯化钠）处理下施氮的叶质量比为0．25g·g-1，是不施氮处理的1．8倍。施氮降低了根比重和根冠比，对茎比重没有显著影响。施氮促进了叶的生长．但抑制了须根的生长。施氮提高了根生物量与叶生物量之间的相关性（R2=O．703，P〈O．01），从而有利于协调植株对资源的有效利用和分配。图1表3参10

Growth of salt stressed Kosteletzkya virginica with addition of nitrogen

Kostelezkya virginica, an important economic plant with strong saline tolerance, was tested to bet- ter understand the effects of nitrogen additions on biomass characteristics and their relationship to K. virginica seedlings undergoing salt stress. Using completely random design, seedlings with 3-4 leaves were exposed for 35 d to treatments of 50, 150, and 250 mmol＇L-1 NaC1 and treatments of 50, 150, and 250 mmol·L-1 NaC1 ＋ 15 mmol·L-1 NH4NO3 with 5 replications. Results showed that N addition significantly increased stem heights （P〈0.05）, but did not affect axial root length. For 50 mmol·L-1 NaC1 ＋ 15 mmol·L-1 NH4NO3, the average stem height was 26.1 cm, but without N it was 18.9 cm; and with N the average axial root diameter was 9.2 mm, but without N it was 6.8 ram. Additionally, leaf-weight ratios increased significantly （P〈0.05） with N addition. Using 250 mmol.L-1 NaC1 ＋ 15 mmol＇L-1 NH~O3, leaf-weight ratios were 0.25 g·g-l, but without N they were 0.14 g·g-l. Root-weight ratios and root-to-shoot ratios significantly decreased （P〈0.05） with N addi tions. Also, N inhibited fine root growth; whereas it promoted leaf growth. Finally, N significantly strength ened （P〈0.05） the relationship between root mass and leaf mass. This could be helpful for utilization and allocation of N in K. virginica seedlings. [Ch, 1 fig. 3 tab. 10 ref.]