施硅对夜间增温条件下水稻叶片生理特性的影响

通过大田试验,研究施硅对夜间增温条件下水稻分蘖期、拔节期、灌浆期、成熟期叶片净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)及胞间CO_2浓度(C_i)的影响。夜间增温设常温对照(CK)和夜间增温(NW)2个水平;施硅量设Si0(不施硅)和Si1(钢渣硅肥,200kg SiO_2·hm~(-2))2个水平。结果表明:(1)夜间增温可使水稻冠层和5cm土层温度升高,水稻冠层和5cm土层全生育期夜间平均温度分别提高1.21℃和0.41℃;(2)夜间增温处理可使生育期内水稻叶片P_n、T_r、G_s比对照分别下降11.0%、9.0%和20.2%,C_i比对照增加1.2%;施加钢渣硅肥处理可使叶片P_n、G_s比对照分别增加16.1%和25.8%,T_r、C_i比对照分别降低11.0%和2.0%;夜间增温条件下施硅比不施硅水稻叶片P_n、G_s分别增加22.0%和33.6%,T_r、C_i分别降低7.7%和2.3%。研究认为夜间增温降低了水稻叶片P_n、T_r、G_s,增加了C_i。施硅通过显著提高水稻叶片P_n、G_s,降低T_r、C_i,缓解了夜间增温引起的抑制效应。(3)夜间增温和施硅两种处理对水稻叶片叶绿素含量(SPAD值)影响不显著。夜间增温使叶片SPAD值平均下降3.0%;施硅使叶片SPAD值增加4.7%;夜间增温下施硅比不施硅叶片SPAD值增加5.7%。

Effect of Silicate Application on Rice Physiological Properties under Nighttime Warming

Field experiment with rice was conducted to investigate the effects of silicate (Si) application on variations of net photosynthetic rate (Pn),transpiration rate (Tr),stomatal conductivity (Gs) and intercellular CO2 concentration (Ci) at the tillering stage,jointing stage,filling stage,maturity stage under nighttime warming.The experiment was designed with two nighttime warming levels,i.e.nighttime warming (NW) and control (CK,ambient temperature),and two Si application levels,i.e.control (Si0) and Sil (slag fertilizer,200kg SiO2·ha-1).The results showed that,(1) nighttime warming increased the temperature of rice canopy and of 5cm depth soil by 1.21 ℃ and 0.41 ℃ at night (19:00-6:00) during entire rice growth season.(2) Nighttime warming decreased Pn,Tr,Gs by 11.0％,9.0％ and 20.2％,but increased Ci by 1.2％.Silicate application increased Pn and Gs by 16.1％ and 25.8％,but decreased Tr andCi by 11.0％ and 2.0％;silicate application increased Pn and Gs by 22.0％ and 33.6％,but decreased Tr and Ci by 7.7％ and 2.3％ under nighttime warming.It is suggested that nighttime warming decreased Pn,Tr and Gs,but increased Ci,in contrast,silicate application increased Pn and Gs,but decreased Tr and Ci.Namely,silicate application mitigated obviously the depressive effects of nighttime warming on photosynthetic properties.(3) The effect of nighttime warming or silicate application on chlorophyll content (SPAD value) was not obvious.Nighttime warming decreased SPAD value by 3.0％,but silicate application increased SPAD value by 4.7％.Compared with Si0,silicate application increased SPAD value by 5.7％ under nighttime warming.