极端干旱区骆驼刺对水氮条件变化的生长响应

采用盆栽试验，研究了不同水氮处理下骆驼刺（Alhagi sparsifolia）的形态特征、生物量累积和分配特征，并探讨了适合骆驼刺生长的最佳水氮条件。经过2年的水氮处理发现，水分和氮素处理对骆驼刺的株高、冠幅、基茎、地上和地下生物量累积均有显著影响，对生物量分配还存在着明显的交互作用，但在不同生长年份影响也不同。在第1个生长年份，综合评价结果为干旱低氮（田间持水量30%~35%，施氮51 mg N·kg^-1）处理下生长表现最好，主要表现在株高、基茎、根系生物量和根冠比均有明显增加。在第2个生长年份，则为中水中氮处理（田间持水量60%~65%，施氮102 mg N·kg^-1）下综合生长表现最好，主要表现在地上、地下生物量和根冠比均有显著增加。因此，在骆驼刺幼苗生长早期应推荐干旱低氮处理，随株龄增加则为中水中氮处理更合适。

Growth Responses of Alhagi sparsifolia under Different Water and Nitrogen Supply Levels in Extremely Arid Region

The potting experiment was conducted to study the changes of morphological characteristics,biomass accumulation and allocation of 1- and 2-year-old Alhagi sparsifolia under different water and nitrogen (N) treatments, and to further find out the suitable combination of water and N for the plant growth. The results showed that plant height, canopy, base diameter, shoot and root biomass were significantly affected by water and N supply. The combination of water and N had a significant influence on the biomass allocation of different organs for both growth stages, but the effects differed with growth age. For 1-year-old A. sparsifolia, the highest comprehensive evaluation value of plant growth was found under drought (30%~35% field water capacity (FC)) and low N (51 mg N·kg^-1) treatment, under which there were significantly higher plant height, base diameter, root biomass and root:shoot ratio compared to the control treatment (drought and no N). For 2-year-old A. sparsifolia, shoot and root biomass and root:shoot ratio were highest under middle water and N treatment (60%~65% FC and 102 mg N·kg^-1) compared to other treatments. Correspondingly, the highest comprehensive evaluation value of plant growth was found under this treatment. This suggests that drought and low N treatment was suitable for A. sparsifolia seedlings in the first year, but middle water and N treatment became more appropriate in the second year.