旨为明确播期和接茬方式对夏玉米羧化酶活性及产量的影响，同时为确定夏玉米与小麦的适宜接茬方式和播种期提供研究依据。2008，2009年进行了4个播期的夏玉米田间试验，6月1，6，11日为“三密一稀”种植的麦田中套种，6月16日为15 cm等行距小麦收获后平播，分别用S06-01、S06-06、S06-11、S06-16表示。生育期间测定羧化酶活性。结果表明，随播期推迟，夏玉米基部第1～4叶的RuBPCase 和PEPCase 活性增强，PEPC／RuBPC 比值减小。棒3叶PEPCase活性随生育进程呈单峰变化，播期早的叶片展开虽早，PEPCase活性高峰出现也早，但后期下降幅度也较大，以致不同处理棒3叶生育期间PEPCase活性的平均值差异并不显著。随播期推迟，棒3叶同叶位叶片光合势与叶源量有减小的趋势，玉米成穗数有增加趋势。千粒质量变化与灌浆期温度密切相关而与播期关系不大，最终产量以S06-16处理较高。处理间经济系数也以S06-16最高或较高，说明产量形成不仅与光合物质生产能力有关，还与光合物质有效转运相关。综上可见，夏玉米平播既保证与套种相同或较高的产量，又便于小麦玉米生产的全程机械化，是较适宜的接茬方式。但为避开集中平播后的浇水高峰，在不早于小麦收获前9 d（6月6日以后）套播，可为夏收夏种期间的农事操作提供较为充足的时间。%In order to clarify the effect of sowing date and interplanting pattern on carboxylase activity and grain yield of summer maize and to provide research support for decision-making on interplanting pattern and sowing date,field experiments were conducted in the years 2008 and 2009.The experiment included four treatments of maize sowing dates,June 1,6,11 seeded inter-rows of previous wheat ,and June 16 directly-seeded after wheat har-vest,and the four treatments were expressed in S06-01,S06-06,S06-11and S06-16 respectively.Carboxylase activities were determined during growing period of maize .The main results showed that ,with delaying sowing dates ,the activities of RuBPCase and PEPCase increased ,and the ratio of PEPC/RuBPC decreased for leaves 1-4 of maize .The PEP-Case activities of the three-ear-leaves of maize showed single peak changes with growing process .Early sowing maize leaves fully expanded earlier ,their peak of PEPCase activity also appeared earlier and decreased more sharply dur-ing late periods.As a result,the difference of average PEPCase activities of three-ear-leaves during growing period among the four treatments was insignificant .The photosynthetic potential and leaf source capacity decreased with de-lay of sowing date , however , the bearing ears of maize increased as sowing date delayed .1 000 grains weight was closely related to the temperature during filling period but less related to the sowing date .The grain yield and the harvest index of directly-seeded summer maize can be the same as ,or higher than ,those seeded inter-rows of previ-ous wheat .Directly-seeding summer maize after wheat harvest was convenient for entire mechanization of wheat -maize double cropping , and therefore the most suitable cropping pattern for wheat-maize production .To avoid the concentrated period of irrigation after summer maize directly-seeding,however,seeding summer maize inter-rows of previous wheat not earlier than nine days before wheat harvest ( after June 6) ,may provide longer period for farming operation during wheat harvest and maize sowing .
展开▼
