不同类型水冷苗床的根际降温效果及其对番茄穴盘苗生长的影响

Root-zone Cooling Effect of Different Water-cooled Seedling Bed and Its Effect on the Growth of Tomato Plug Seedlings

为了降低夏季蔬菜集约化育苗时幼苗的根区高温环境,利用地下水作为循环媒介,设计了用于根区降温的水冷苗床。试验分别采用金属梯形管(M)和塑料圆管(P)作为冷水管,以未采用根区降温的苗床为对照,研究两种水冷苗床的根区降温效果及其对番茄幼苗生长的影响。结果表明,两种水冷苗床番茄幼苗根区日均温、白天均温和最高温度均显著低于对照苗床(P<0.05)。M式和P式苗床番茄幼苗根区日均温分别为23.2℃和26.0℃,全天根区温度高于25℃的历时为8.3h和11.6h,分别比对照苗床减少7.5h和4.2h。水冷苗床显著促进了番茄幼苗生长和干物质积累,提高了番茄幼苗茎流速率、根系呼吸速率和光合能力,M式和P式水冷苗床番茄幼苗单株干质量依次为4.52和3.90mg,分别比对照(2.85mg)增加58.6%和36.8%(P<0.01)。两种水冷苗床番茄幼苗的壮苗指数和根冠比均显著高于对照。综合根区降温效果和番茄幼苗生长来看,M式水冷苗床更有利于番茄幼苗的生长。

In order to alleviate high root-zone temperature injury on intensive seedling production during hot summer. A water-cooled seedling bed was designed, in which underground water was used as the natural coolant. Two different water-cooled seedling beds were exploited in this experiment. Metal stainless steel tube（M-type cooled-bed） and plastic tube（P-type cooled-bed） were used as cooling tube respectively. The seedling bed without root cooling system was used as control（CK）.The cooling effect of two different water-cooled seedling bed and its effect on the growth of tomato seedling were investigated. The results showed as follows： the cumulative temperature, mean daily temperature and mean daily maximum temperature of the root-zone both in M and P-type cooled-bed were lowered significantly compared with those of non-cooled seedling bed（CK）. The mean daily temperature of M and P-type cooled-bed were 23.2℃ and 26.0℃. The mean high temperature duration of M and P-type cooled-bed above 25℃ was 8.3h and l l.6h per day, which were shortened by 7.5h and 4.2h respectively compared with control＇s seedling-bed. The growth rate and dry mass accumulation of tomato seedling both in M seedling-bed and P seedling-bed were enhanced significantly, and sap flow velocity, root respiration rate and net photosynthetic rate were also improved. Dry mass of per plant of tomato seedling in two cooled-bed were 4.52mg（M） and 3.90mg（P）, which were increased by 58.6% and 36.8% respectively compared with control. Tomato seedling healthy index and the ratio of root to shoot both in two cooled-beds were apparently higher than control. Water-cooled seedling bed was an effective way to lower the root-zone temperature and it could improve tomato seedling growth during hot summer. The M-type cooled-bed was more beneficial to enhance the growth of tomato seedlings.