| Turf is one of the important indicators to measure the civilization and development of a country or city.In recent years,the use of lawns in urban greening construction in China has been increasing.The turf also plays an irreplaceable role in the process of deepening the construction of beautiful China and fully implementing the "hills?water?lakes?grass" as a community of life.However,the problem of guilt caused by heavy rainfall and the drought in summer will affect the normal growth of the turf.At present,there are few studies on the water adaptability of turfgrass roots at home and abroad.Therefore,exploring the adaptability of turfgrass roots to different water conditions can provide guidance for the water management of turfgrass during planting,and also provide certain for its garden application.The theoretical basis for scientific and reasonable irrigation.In this experiment,a pot experiment was conducted in a greenhouse,and two varieties of Lolium perenne and Poa pratensis were used as test materials to simulate light rain(24-hour precipitation 0.1-9.9mm),moderate rain(24-hour precipitation of 10-25mm),heavy rain(24-hour precipitation of 25-50mm),three types of precipitation and set CK control group(Watering is 60%of the light rain group),set to A,B,C,CK,studied the change trend of root architecture and the response of root anatomy to water in a certain growth cycle,and the susceptibility analysis was carried out by using membership function analysis method.The main experimental results are as follows:1.The total root length,root surface area,root volume and root diameter of Lolium perenne in the stress cycle,the CK,A,and C in the water treatment group increased first and then decreased,and the growth of 26-3 8d was the largest.The moisture treatment group C had the best growth,and the growth of CK and A group was basically the same.Under the condition of treatment group C,the root length,root surface area,root volume and root mean diameter continued to increase at 38?44d but the increase was lower than the first 38d,and began to decrease after 44d.The root length of CK group and A group was 38-44d.The root volume and root mean diameter were basically unchanged,and the root surface area decreased slightly.After 44 days,all indexes decreased significantly,and the drought was severe at 44?50 days,which affected plant growth.The root length,root surface area,root volume,root mean diameter and root branch number of the B treatment group did not decrease during the whole stress period,and the root length increased by 521.23 cm,the root surface area increased by 53.54 cm2,and the total root volume increased by 0.19 cm3.The average diameter of the root increased by 0,128 mm,and the number of root bifurcations increased by 138,indicating that the perennial ryegrass had the strongest adaptability to the B water treatment group.The change trend of root bifurcation number is slightly different from other indicators.Within 44 days of stress,the four groups all increased significantly,and the B and C groups increased greatly,indicating that the more water,the more the number of branches,when the 50d,The number of forks of B exceeds the C group,and the other groups are basically unchanged,indicating that the B group is the optimum moisture,which is the same as the other indicators.2.The root length,root surface area,root volume,root mean diameter and root number of Poa pratensis in the water treatment group all showed an upward trend within 38 days before the stress cycle,and the CK group and the A group were basically consistently,the increments of group B and group C were larger,indicating that the greater the water concentration during the period,the stronger the growth promotion effect of the root system of the bluegrass.The root length,root surface area and root volume of the CK group and the A group were all 38?50d.In order to increase slowly and then decrease significantly,the average root diameter and the number of root branches did not change,indicating that the roots of these two groups were relatively dry and slow to grow.As the drought increased,death or shedding roots began to appear.At 38 days,the total root length of the roots of the bluegrass of the group C began to decrease.The root surface area,root volume and root diameter showed a slight increase and then decreased continuously.The number of root bifurcations increased slightly,indicating that the soil moisture content was greater than the root requirement after 38 days of stress.The amount affects the normal breathing and growth of the roots.Under the water condition of group B,the stress period of the roots of Poa pratensis was good,and the root length increased by 612.33cm,the root surface area increased by 41.56cm2,the root volume increased by 0.27cm3,the root average diameter was 0.092mm,and the number of root bifurcations increased 113,the whole cycle of stress,the B group is the most ideal,indicating that the water condition of group B is most suitable for the growth of the roots of bluegrass.Although the growth of the group C is good in the middle and middle stages,the watering amount obviously exceeds the demand of plants and does not meet the economic irrigation requirements.3.When water deficit occurs,the root biomass distribution of the two turfgrasses will increase,and the root-shoot ratio will become larger.With the extension of drought time,the root biomass will become smaller,the root-shoot ratio will become smaller,and the roots will become smaller.The crown ratio became larger and slowed down later.The more severe the drought or leeches,the stronger the roots of the two turfgrasses will be more intense than the root biomass,and the larger the SRL.After a while,the SRL becomes smaller again,indicating that long-term adverse conditions will cause a significant decrease in root length,and biomass will not change significantly.Drought stress can significantly increase the dry weight of two turfgrass roots,and increase the contact area between roots and soil.RWD increases.After a certain time,the drought is intensified,the root biomass is significantly reduced,and the volume change response is less than the root dry weight.RWD decreased,RWD increased in the early stage of waterlogging stress,and the later changes were smaller.The drought was prior to the change of roots in the waterlogging reaction.Among them,the indicators of water treatment group B were stable,and the difference was significant with other groups.It was also suitable for the growth of turfgrass in terms of growth.4.The morphological characteristics of the root anatomy of the four group ryegrass Lolium perenne were basically the same at 26d.At 32d,the root anatomy of the water treatment in group C was significantly different from that of CK,A and B,indicating that the root system was under stress.On the 26th day,the response to the water treatment of the simulated heavy rain in Group C was expressed.Group A also showed mild symptoms of drought,and group B grew normally.In group C,the root structure damage was severe due to excessive long-term water.In the CK group,the root anatomy showed normal growth at 26?3 2d,and was not affected by water loss.From 38d,there was mild water shortage,and there was atrophy of the column and cortical damage.At 44d,the water shortage was serious and the root structure was affected.The root anatomy of group A showed good root status at 26?38d.As the plant increased with time,the biomass increased and the required water gradually increased.At 44 days,the moisture of group A could not meet the growth demand.At this time,the root system There was a slight water shortage.In the whole water treatment process of group B,the growth of the group B remained stable and stable,indicating that the water condition of group B was the most suitable for the growth of bluegrass;the water of group C appeared at 32d.At 32-44d,the symptoms gradually worsened.5.The root anatomical structure of Poa pratensis under different water gradient treatments showed that the four treatments grew well at 26?32d,indicating that the short-term water difference did not affect the grass;the CK showed mild drought at 38d.Injury,the difference between A and B was not obvious,the root structure was intact,the water was swollen in group C,the middle column was obviously reduced,and the cortical cells were damaged.On the 44d,the CK group continued to be affected by drought stress,and the root structure was damaged.The diameter of the column and the catheter was significantly smaller,and the proportion of the root diameter was decreased.The mild drought symptoms were observed in group A,the root anatomy was normal in group B,and the water was swollen in group C.6.The root growth of perennial Lolium perenne and Poa pratensis depends on water.If heavy rain lasts for 26?30d,it will cause flooding,and then it will inhibit root growth.Continuous drought and low watering will also affect normal.The growth environment of the root system is simulated by moderate rain stress,that is,the 24-hour precipitation is 10-25mm.The tolerance of the two turfgrass was evaluated by the membership function method,and it was concluded that the resistance of the Poa pratensis>Lolium perenne. |
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