穗分化期旱涝急转对双季超级杂交稻物质积累和产量形成的影响

采用桶栽方式,以超级杂交早稻品种(淦鑫203)、超级杂交晚稻品种(五丰优T025)为材料,于穗分化初期设置不旱不涝(对照CK)、轻旱不涝(T11)、重旱不涝(T2)、不旱轻涝(T3)、不旱重涝(T4)、重旱轻涝(T5)、重旱重涝(T6)、轻旱轻涝(T7)和轻旱重涝(T8)处理,分析各处理产量及其构成因素、干物质积累与分配和净光合速率等指标。结果表明:(1)"旱"、"涝"及"旱涝急转"使超级杂交早、晚稻单株产量不同程度下降,早稻T1、T2、T3、T4、T5、T6、T7和T8单株产量分别比CK降低8.89%、21.42%、8.33%、12.04%、19.65%、31.23%、15.39%和17.29%,晚稻分别降低6.21%、15.06%、7.77%、11.53%、17.40%、20.85%、13.46%和11.70%,早、晚稻以T2和T6处理产量下降较多,尤其T6处理产量降幅最大,表明单纯前期轻旱(T1)和后期轻涝(T3)对产量的影响相对较小,而单纯前期重旱(T2)和后期重涝(T4)对产量的影响相对较大,T2比T4对产量的影响更大,且重旱重涝处理下水稻单株产量存在一定程度的叠加减产效应。产量构成上,早、晚稻产量下降的主要原因是较大幅度降低了单株有效穗数、每穗总粒数、结实率和二次枝梗数,各处理对产量构成的影响规律与单株产量大致相同。(2)早、晚稻"旱"、"涝"及"旱涝急转"等处理结束初期与CK比较,其茎、叶干物质量均不同程度下降,其中早、晚稻成熟期T6处理穗干物质量分别比CK下降33.40%、19.88%,表现为穗型变小。(3)"旱"、"涝"及"旱涝急转"使早、晚稻叶片叶绿素含量(SPAD值)降低,其中早、晚稻均以T6处理的SPAD值降幅最大,且与CK一直呈显著性差异。(4)至抽穗期,早、晚稻叶片净光合速率均以T6处理最低,分别比CK下降37.57%、10.17%。研究结果说明,生长前期重旱后期急转重涝对早、晚稻成熟期穗部干物质量及总干物质量的影响最大,重旱重涝急转表现为叠加损伤效应。

Effects of Drought-floods Abrupt Alternation During Panicle Differentiation Stage on Matter Accumulation and Yield Formation in Double-season Super Hybrid Rice

In this study, pot experiments were performed and super hybrid early rice(Ganxin 203) and late rice(Wufengyou T025) were selected as the material. During panicle differentiation initiation stage no drought in earlier stage and no floods in later stage(control, CK), mild drought in earlier stage and no floods in later stage(T1), severe drought in earlier stage and no floods in later stage(T2), no drought in earlier stage and mild floods in later stage(T3), no drought in earlier stage and severe floods in later stage(T4), severe drought in earlier stage and mild floods in later stage abrupt alternation(T5), severe drought in earlier stage and severe floods in later stage abrupt alternation(T6), mild drought in earlier stage and mild floods in later stage abrupt alternation(T7), mild drought in earlier stage and severe floods in later stage abrupt alternation(T8) were set. While the indices of the yield and its components, dry matter accumulation and distribution and net photosynthetic rate(Pn) were investigated. The results showed that, (1) the yield per plant in super hybrid early and late rice was decreased in different degrees under "drought", "flood" and "drought-floods abrupt alternation". Compared with CK, the early rice T1, T2, T3, T4, T5, T6, T7 and T8 yield per plant were decreased by 8.89%, 21.42%, 8.33%, 12.04%, 19.65%, 31.23%, 15.39% and 17.29%, respectively. The late rice were decreased by 6.21%, 15.06%, 7.77%, 11.53%, 17.40%, 20.85%, 13.46% and 11.70%, respectively. The yield of T2 and T6 treatments in early and late rice was decreased more, especially the yield of T6 treatment was largest decline, it was shown that only mild drought or mild floods on yield were less affected, but only severe drought or severe floods on yield were relatively large affected, and severe drought was greater affected than severe floods on yield. As for rice plants treated with severe drought in earlier stage and severe floods in later stage abrupt alternation, a certain degree of superimposition and reduction effect was existed. In the yield components, the main reasons for the yield decreased by effective panicles per plant, number of grains per panicle, seed setting rate and secondary branch number. The effects of yield and yield components were roughly the same among treatments. (2) Compare with CK, stem and leaf dry mass were decreased in different degrees in early and late rice under "drought", "flood" and "drought-floods abrupt alternation". Among the early and late rice at mature stage, the panicle dry mass of T6 treatment decreased by 33.40% and 19.88%, respectively, compared with CK, and the panicle shape becomes smaller. (3) The leaf chlorophyll content(SPAD value) in early and late rice was decreased under "drought", "flood" and "drought-floods abrupt alternation". SPAD value of T6 treatment in early and late rice were decreased remarkably, and with CK has a significant difference. (4) Leaf Pn of T6 treatment in early and late rice was the lowest, decreased by 37.57% and 10.17%, respectively, compared with CK. The results of the study were illustrated that severe drought in earlier stage and severe floods in later stage abrupt alternation had the maximum influence on panicle dry mass and total dry mass at mature stage in early and late rice, and severe drought in earlier stage and severe floods in later stage abrupt alternation showed a superposition damage effect.