CAJ | 학술논문

维持较高的光合作用对于作物适应干旱逆境意义重大,光合电子传递和气孔行为是作物光合机构的重要组成部分,而玉米上有关它们之间的组合响应干旱胁迫研究报道较少。本文将2个主推玉米品种陕单609和郑单958生长在自然光和4个干旱胁迫下的干旱棚内,对其叶片的光系统II (PSII)的电子传递功能和气孔导度进行了研究。结果显示,中度和重度干旱胁迫下2个品种叶片净光合速率(Pn)和气孔导度(Gs)显著下降,而伴随着胞间CO2浓度(Ci)上升,显示光合速率下降是非气孔因素所致。JIP-test分析发现干旱胁迫下2个品种叶绿素荧光诱导动力曲线(OJIP)中出现了K-band,说明光系统II (PSII)放氧复合体(OEC)受到抑制和PSII供体侧与受体侧电子传递不平衡；同时干旱胁迫下反映从PSII供体侧到PSI末端受体电子流的荧光参数显著改变,损伤了光系统II和I之间光合电子传递链,限制CO2同化。品种间光合特性对干旱胁迫的响应存在差异,重度干旱对郑单958叶片光合机构的影响比对品种陕单609大。以上结果表明,中度和重度干旱下玉米品种叶片Pn下降归属于光化学活性的衰退；陕单609光合机构的耐旱性强于郑单958。
유지교고적광합작용대우작물괄응간한역경의의중대,광합전자전체화기공행위시작물광합궤구적중요조성부분,이옥미상유관타문지간적조합향응간한협박연구보도교소。본문장2개주추옥미품충협단609화정단958생장재자연광화4개간한협박하적간한붕내,대기협편적광계통II (PSII)적전자전체공능화기공도도진행료연구。결과현시,중도화중도간한협박하2개품충협편정광합속솔(Pn)화기공도도(Gs)현저하강,이반수착포간CO2농도(Ci)상승,현시광합속솔하강시비기공인소소치。JIP-test분석발현간한협박하2개품충협록소형광유도동력곡선(OJIP)중출현료K-band,설명광계통II (PSII)방양복합체(OEC)수도억제화PSII공체측여수체측전자전체불평형；동시간한협박하반영종PSII공체측도PSI말단수체전자류적형광삼수현저개변,손상료광계통II화I지간광합전자전체련,한제CO2동화。품충간광합특성대간한협박적향응존재차이,중도간한대정단958협편광합궤구적영향비대품충협단609대。이상결과표명,중도화중도간한하옥미품충협편Pn하강귀속우광화학활성적쇠퇴；협단609광합궤구적내한성강우정단958。
Maintaining active photosynthesis is very important for crops to adapt drought stress. The electron transport chain and stomatal conductance are important in photosynthesis. Limited data are available on their combined responses to drought stress in maize. In this paper, the effects of drought stress on photosynthetic characteristics in maize hybrids Shaandan 609 and Zhengdan 958 at seedling stage were investigated. The results showed that the CO2 assimilation (Pn), stomatal conductance (Gs) and inter-cellular CO2 concentration (Ci) decreased during drought stress, showing the decreased photosynthesis due to stomatal factor. During moderate and severe drought stress, down-regulation in net CO2 fixation (Pn) was primarily mediated through non-stomatal limitation. The OJIP transients and other associated biophysical parameters elucidated the events of photoacclima-tory changes in photosystem II (PSII) with progressive increase of drought stress, and the K-bands appeared in the stage of ex-treme drought severity indicating the imbalance between the electrons at the acceptor and donor sides of PSII, which suggested the oxygen-evolving complex (OEC) and electron transport were inhibited. In conclusion, the moderate and severedrought stress mainly damages the electron transfer from the plastoquinone (PQ) pool to the PSI terminal acceptors; this, along with constraints to both stomatal and non-stomatal components of photosynthesis, limits carbon assimilation. There are differences in cultivars with the response of PSII activity to drought stress.