保水剂（SAP）是一种应用较为广泛的化学节水材料，能够促进土壤水分增加，改善土壤结构，但 是在频繁干湿交替的环境中，保水剂的长效性及其有效性的影响因素尚不明确。本研究中，土壤中混施不 同用量的保水剂（0%，0.1%，0.2%和0.3%），研究在连续三次失水-复水条件下（T1、T2和T3），保 水剂对土壤结构和水分物理性质的影响效应。结果表明，当土壤处于轻度干旱（T2）和充分灌溉（T3）时， 用量为0.2%和0.3%的保水剂可以提高土壤的供水能力；但在重度干旱（T1）条件下，保水剂反而会降低 土壤的供水能力；且这种变化趋势与保水剂用量呈负相关。保水剂与土壤中的Si-O-Si键、-OH，以及不同 的结晶二氧化硅等矿物胶体之间的物理吸附和化学作用是直接导致干湿交替条件下保水剂持水性能降低的 重要因素之一。与对照相比，保水剂处理组的土壤液相比显著增加了8.8%~202.7%，T1和T2处理尤为明 显，引起土壤气相比显著降低。经历反复的干湿交替过程，尤其当保水剂用量较大时，保水剂处理组会显 著增加>0.25 mm的土壤团聚体和水稳性大团聚体（R_0.25）的含量，减低<0.053 mm的土壤团聚体含量。 保水剂处理组平均重量直径（MWD）和几何平均直径（GMD）的增加，以及分形维数（D）和不稳定团粒 指数（E_LT）数值的下降，说明保水剂可以大幅改善土壤结构的稳定性。综合分析认为，土壤团聚体的分 布和结构稳定性，以及土壤供水能力的改善与保水剂用量、土壤水分状况，以及保水剂和土壤颗粒之间的 相互作用密切相关。

Using scanning electron microscopy, we investigated the distribution of the trichoid, basiconic, and coeloconic sensilla on the antennae of the diamondback moth (DBM; Plutella xylostella). The trichoid sensilla were the most abundant sensory organ, and the male moth antennae host significantly more trichoid sensilla than female moth antennae. Conversely, basiconic and coeloconic sensilla were found more frequently on female than on male antennae. We performed experiments with various degrees of antennal ablation and demonstrated that DBM antennae played a key role in the control of mating and oviposition. We found that neither oviposition preference nor mating behaviors changed significantly when less than 1/4 of both antennae were removed. However, there was a significant behavioral change when the antennae were ablated by more than half. As the length of the antenna was shortened, the successful mating rate decreased and mating peak was delayed. An otherwise consistent host preference for oviposition was eliminated when both antennae were completely removed. Furthermore, we found that the number of trichoid sensilla was positively correlated with mating rate and oviposition preference. However, the numbers of basiconic and coeloconic sensilla were not correlated with mating rate and mating peak, but highly correlated with oviposition preference. Taken together, our results indicate that antennal sensory information plays a critical role in the mating and oviposition behaviors of this economically important pest.