Effects Of Precipitation Changes In The Desert Area Of The Hexi Corridor On The Life History Of Typical Annual Herbaceous Plants

The annual herb was an important part of the vegetation in the desert area of the Hexi Corridor.The change in precipitation has an important impact on the life history of the plant.What breeding countermeasures to ensure the success of its reproduction has attracted the attention of many scholars.This paper focuses on the study of precipitation reduction on the plant height,leaf number,root length,reproductive phenology,biomass allocation,and root-to-shoot ratio.of typical annual herb Setaria viridis?Chloris virgata?Bassia dasyphylla and Salsola ruthenica through simulated rainfall control experiments.This paper discusses the growth and characteristics of plants distribution and change in a reduced precipitation environment.The results show:(1)precipitation decreasing leads to a decrease in the height of the four annual herbaceous plants,which was not conducive to plant growth.This study found that the precipitation reduction at the jointing stage(chenopodiaceae plants was leaf-expansion period)had the greatest impact on plant height(including the height change of Chloris virgata and Salsola ruthenica plant reached a significant difference(p<0.05)).At this time,plants were mainly vegetative,and plants needed to grow and occupy quickly.The precipitation reduction in space,flowering period and fruit ripening period had little effect on plant height.At this time,the main growth was reproductive growth,and plant height changes little,however,these were insignificant.The precipitation reduction led to 4 annual herbaceous plants.The reduction in the number of leaves was not conducive to the photosynthesis of plants.This study found that the reduction in the number of precipitation reduction at the jointing stage(chenopodiaceae plants was leaf-expansion period)has the largest reduction in leaf number.The plant needs to accumulate biomass through photosynthesis.The precipitation reduction in the flowering and fruit ripening periods reduce the reduction of plant leaves.It was smaller,but no significant difference was founded;the reduction of light precipitation events leads to shorter plant root length,which was not conducive to plant growth.This experiment concluded that the precipitation reduction at the jointing stage(chenopodiaceae plants was leaf-expansion period)has the greatest effect on root length.However,only the root length of sage and sedge was reduced to a significant level.(P<0.05),the precipitation reduction in the flowering and fruit ripening stages had less effect on plant root length;the plant height growth of Chenopodiaceae(Bassia dasyphylla and Salsola ruthenica)was relatively uniform,and the relative growth height of the plants was the largest.Poaceae plants(Setaria viridis and Chloris virgata)plants rapidly increased at the jointing stage(chenopodiaceae plants was leaf-expansion period),and the relative growth height of the plants was relatively low.The plant heights of the four annual herbaceous plants stopped changing at the end of flowering.The number was small,and it stops changing at the flowering stage.The leaves of the Chenopodiaceae(Bassia dasyphylla and Salsola ruthenica)have small but many leaves,and the leaf number stops changing at the end of flowering.(2)Decrease in precipitation reduction led to a decrease in above-ground biomass of four annual herbaceous plants.This study found that the decrease in precipitation reduction at the jointing stage(chenopodiaceae plants was leaf-expansion period)had the greatest impact on above-ground biomass,and that the decrease precipitation reduction during the flowering and fruit ripening periods had an impact on above-ground biomass.The impact was little,but the impact on the four plants has not reached a significant level;the decrease in precipitation reduction has led to an increase in the underground biomass of the four annual plants,and the decrease in precipitation reduction at the jointing stage(chenopodiaceae plants was leaf-expansion period)has the greatest impact on the plants,and the underground biomass has increased the most.However,only the growth of Chloris virgata has reached a significant level(p<0,05).Increasing in underground biomass during the fruit ripening period was greater than that during the flowering period,which may be due to the longer duration of the fruit ripening period;the reduction of light precipitation events on the roots of four annual herbaceous plants was significant at the jointing stage(chenopodiaceae plants was leaf-expansion period)about the crown ratio effect.The roots and crowns of the two grass species(Setaria viridis and Chloris virgata)were relatively large,which may be due to the error caused by the roots of other plants remaining during the sampling process of the grasses as fibrous root plants.Straight-root plants have no residual roots that cause errors.(3)The reduction of precipitation reduction will not affect the above-ground and underground growth of four annual herbaceous plants.The value of the fitting parameter R~2value was between 0.802-0.934,and there was no obvious change rule,precipitation reduction reduce the seed biomass of 4 annual plants,of which plant seed biomass decreases the most during precipitation reduction at jointing stage(chenopodiaceae plants was leaf-expansion period),and precipitation reduction during flowering and jointing stage(chenopodiaceae plants was leaf-expansion period)reduce seed biomass and seed ripening,and fruit ripening stage.The precipitation reduction caused a decrease in seed biomass more than the decrease in seed weight during flowering,which may be caused by the duration of the fruit ripening period being longer than the flowering period;the precipitation reduction delayed the flowering period,and the fruit ripening period was delayed accordingly.The delay time of different plants was not the same.The precipitation reduction,and the phenological period was also smaller.The precipitation reduction at the jointing stage(chenopodiaceae plants was leaf-expansion period)has no effect on the reproductive input of 4 annual herbaceous plants.Reduced precipitation during flowering and fruit ripening has little effect on reproduction inputs,but neither has reached a significant level.The fitting parameter R~2value was between 0.84-0.94.