The Research On The Effect Of Low Temperature On Three Kinds Of Pilea Lind1. Plant

Pilea cadierei Gagnep、Pilea nummulariifollia and Pilea purpurella resistance trim, easy cultivation, negative resistance is strong, green sleek, fresh and beautiful, has a very considerable ornamental value and great potential applications of the garden. In order to explore three kinds of plants’ ability of cold-resistant, use manual climatic box,studies effet of the low temperature stress treatment on three species about growthform and physiological characteristics.The test’s results show:(1) Growth form:On 45th days in stress, Pilea purpurella in 0℃ environment while is restrained, but still can normal growth; Pilea nummulariifollia 0℃ group appeared death at 6th day,5℃ group appeared death at 17th day, at 10℃ environment can be normal growth; Pilea cadierei Gagnep 15th days spent in stress,0 ℃ group plants all died on 12nd day,5℃ group can grow normally. At the low temperature condition, the three kinds of plants’ arrangement about external form of performance is Pilea purpurella,Pilea cadierei Gagnep. Pilea nummulariifollia.(2) Chlorophyll content:On 45th days in stress, test plants’ chlorophyll content presented decline trend, Pilea cadierei Gagnep on 45th days to achieve the lowest 19.20% at 5℃ group, significantly different with CK group; Pilea purpurella’s 0℃ group while in 45th days to reach the lowest 17.10%, but with the CK group did not reach significantly difference; Pilea nummulariifollia reached 13.30% minimum at 10 ℃ group, and CK group reached significantly difference.the chlorophyll content of three species amplitude of decline trend is Pilea nummulariifollia> Pilea cadierei Gagnep> Pilea purpurella.(3) Relative conductivity:under the low temperature stress, the value of the relative conductivity of Pilea nummulariifollia at the rising trend, when the plants under 15℃ group,the value reached lowest 10.62% on 5th day,Reached significant difference with the CK group, On 35th days, the maximum 49.46% appeared on 10℃ group, and CK group reached significant difference. Pilea purpurella reached the maximum 44.61% at 0℃ group on the 45th days.The variation among the plants, Pilea cadierei Gagnep is the largest, the second is Pilea nummulariifollia, smallest change is Pilea purpurella.(4) Relative water content:under the low temperature condition, three kind of plants appeared on decline trend, but the change is small.(5) Fluorescence kinetics parameters:under low temperature stress, Pilea cadierei Gagnep, Pilea nummulariifollia and Pilea purpurella’s Fo values are within the scope of the smaller rise by volatility,.Fo values sort of Pilea purpurella> Pilea nummulariifollia>Pilea cadierei Gagnep, three kinds of plants under low temperature stress light energy utilization ability for Pilea cadierei Gagnep>Pilea nummulariifollia>Pilea purpurella. Under low temperature stress, the three kinds of plants’ FV/FM values of each processing showed a trend of decrease, the FV/FM declines from big to small Pilea purpurella, Pilea cadierei Gagnep, Pilea nummulariifollia; Pilea cadierei Gagnep and Pilea nummulariifollia’s qP value showed a trend of decline, Pilea purpurella’s 15℃ group and 10℃ group showed a trend of rising.5℃ and 0℃ showed a trend of decline. The degree of decline about ETR from big to small is Pilea cadierei Gagnep、Pilea nummulariifollia、Pilea purpurella.Fv/Fm value as the extension of time get lower, and the order is Pilea nummulariifollia> Pilea cadierei Gagnep> Pilea purpurella;Overall, three kinds of plants only pPilea purpurella’s ability of against cold is strongest, can grow normally under 0℃ stress; Pilea cadierei Gagnep can grow in 15 ℃ to 5℃ low temperature environment, can fight eight days 0℃ low temperature; Pilea nummulariifollia can grow in 15℃ to 10℃ low temperature environment, can fight 17 days 5℃ low temperature environment,6 days 0℃ low temperature environment. Three plants’ ability of cold resistance from strong to weak for the Pilea purpurella, Pilea cadierei Gagnep, Pilea nummulariifollia.