硅对低温胁迫后檀香紫檀苗木生长和光合生理的影响

Effects of Silicon on Growth and Photosynthetic Physiology of Red Sandalwood Seedlings after Cold Stress

摘要:

为探究硅（Si）对檀香紫檀（Pterocarpus santalinus）抗寒性的影响，对1年生苗木施Si后经（-3±0.5）℃胁迫24 h恢复栽培90 d的生长、叶片光合参数和4种碳同化关键酶活性进行了研究。结果表明，施Si的檀香紫檀苗木发育健壮，抗寒性提高，显著促进低温胁迫后的生长恢复；施Si显著抑制低温胁迫导致的檀香紫檀苗木叶绿素含量降低和叶绿素a/b减小，促进表观光合电子传递速率（ETR）、实际光量子效率Y（Ⅱ）和PSⅡ调节性能量耗散Y（NPQ），降低PSⅡ非调节性能量耗散Y（NO）和非光化学荧光淬灭（NPQ）；施Si提高受低温胁迫檀香紫檀苗木的光合速率（Pn）、气孔导度（Gs）和水分利用效率（WUE）；施Si的檀香紫檀苗木在低温胁迫后，核酮糖-1，5-二磷酸羧化酶（Rubisco）、果糖-1，6-二磷酸酶（FBP）、果糖-1，6-二磷酸醛缩酶（Ald）、磷酸烯醇式丙酮酸羧化酶（PEPC）活性显著提高。适量施Si有利于保持低温胁迫下苗木光合膜结构的完整性和生理功能的稳定性，是提高檀香紫檀苗木抗寒性、有效应对低温胁迫的营养管理措施。

Abstract:

To explore the effect of Si nutrition on cold resistance of red sandalwood (Pterocarpus santalinus), one-year-old seedlings applied silicon (Si) for 180 d were suffered (-3±0.5)℃ stress for 24 h, and then recovered for 90 d in greenhouse, the growth status, leaf photosynthetic parameters and activities of four key enzymes related carbon assimilation of the seedlings were studied. The results showed that the seedlings applied Si were strong, growth recovery was fast after cold stress, the cold resistance was significantly improved. After applied Si, the decreases of chlorophyll content and Chl a/b of seedlings caused by cold stress were significantly inhibited, the apparent electron transfer rate (ETR), actual photon efficiency Y(Ⅱ) and PSⅡ regulatory energy dissipation Y(NPQ), and reduced the proportion of PSⅡ non-regulated energy dissipation Y(NO) and non-photochemical quenching (NPQ) were all promoted, and the leaf photosynthetic rate (Pn), stomatal conductance (Gs) and water use efficiency (WUE) of red sandalwood seedlings under cold stress increased after applied Si. The activities of four key enzymes related carbon assimilation, such as ribulose-1,5-bisphosphate carboxylase (Rubisco), fructose- 1,6-phosphatase (FBP), fructose-1,6-bisphosphate aldolase (Ald) and phosphoenolpyruvate carboxylase (PEPC), of seedlings applied Si were significantly higher than those of non-applied Si. Therefore, application of the appropriate amount of Si benefits the integrity of photosynthetic membrane structure and stability of physiological functions of seedlings under cold stress, and it is an effective nutrient management measure improving the cold resistance and coping with cold stress of red sandalwood seedlings.