| From April to October in 2004, amicro-plot epxeriment was conducted in the semiarid area of Laizhou to study the effects of irrigation with mariculture wasterwater blended with slightly saline ground water on growth and yields of Helianthus tuberosus L. The results showed that the irrigation with fresh water could remarkably hasten the stem growth, but the stem height of other treatments were restrained due to water or salt stress. The stem width of 1∶3 and 1∶4 treatments was the largest, being 3.0 cm and 2.97 cm respectively; that of CK1, CK2 and 1∶2 treatment was 2.90, 2.83 and 2.73 cm, respectively; and that of 1∶1 treatment was the smallest, being 2.63 cm. The abovegrouned biomass of CK1 reached the highest value of 2.92 kg/plant; that of CK2 was the next; and that of 1∶1, 1∶2, 1∶3 and 1∶4 treatments was decreased by 26.4%, 29.1%, 21.6% and 17.5% respectively, when compared with CK1. The underground biomass of 1∶4 treatment was 0.623 kg/plant; that of CK2 was the next; and that of 1∶1 treatment was the lowest, being 0.368 kg/plant. Therefore, water stress could accelerate the growth of stems, leaves and roots of Helianthus tuberosus L., but restrain the growth of tubers. Using low concentration of maricultwre wasteuater blended with slightly saline water to irrigate Helianthus tuberosus L. could improe dry matter acumulation of tubers, thus achieving high yields. |