Effect of Substrate Relative Water Content in Seedling Hardening Stage on Storage Characteristics of Cucumber Seedling
LI Juan-qi1，YANG Tian1，PAN Xiao-bing1，TIAN Yong-qiang1，ZHAO Jing-wen2，CHEN Qing-yun1，GAO Li-hong1*
1College of Agronomy & Biotechnology，China Agricultural University，Beijing Key Laboratory of Growth and Development Regulation for Protected Vegetable Crops，Beijing 100193，China；2Beijing Agricultural Technology Extension Station，Beijing 100101，China
Abstract：To explore the effect of substrate moisture in seedling hardening stage on storage characteristics of commercial cucumber seedling，substrates of cucumber seedlings in hardening stage were treated with different water contents， their growth indicators related to quality during different storaging time，and the recovered growth indicators after transplanting were also measured. Single and composite indicators for evaluating storaging quality of cucumber seedlings were screened. The results show that with the increase of storaging time，the leaf integrity index，starch contents，and leaf growth rate of cucumber seedlings under all substrate moisture treatments were decreased. On the whole，storage for 0 day（direct transplanting），under treatment with substrate relative water content between 45%-55 %，the seedlings grown had the best recovery after transplanting. Storage for 2 days，under treatments with substrate relative water content between 30%-40% or 45%-55 % in seedling hardening stage，the various indicators of cucumber seedlings and their recovery abilities after transplanting presented well.Storage for 4 days，seedling quality deterioration was obvious，but there were no significant differences between all treatments. Storage for 6 days，only under the treatment with substrate relative water content between 75%-85%，the cucumber seedlings could resume growth after transplanting. By correlation analysis we concluded that the leaf integrity index of cucumber seedlings in storaging period had the highest correlation coefficient with their growth resume abilities after transplanting，which could be taken as the single indicator. Through path analysis，we believed that the composite index of‘soluble sugar content（mg· g-1 ，FW）+86.24 specific leaf weight （g·dm-2）-474.56 underground root dry weight（g） ’could well reflect the seedling growth recovery ability after transplanting .
