Analysis Of Formtion Mechanism Of Pea Parchmented Pod And Effect Of Sowing Dates On Yield Characters Of Pea Shoots

Edible pod pea and parchmented pod pea are two different types of pea according to whether they have a hard membrane (parchment) in pod or not. We used two pea varieties LIB and MICUI from two different types of pea to investigate the formation mechanism of"parchment". For this reason, the contents of cellulose, hemicellulose, and lignin were measured as well as the activities of pheylalanine ammonia-lyase(PAL), cinnamyl alcohol dehydrogenase (CAD) and peroxidase(PO) at different growth periods of pod. The results showed that the main difference between two types of pea occurred in endocarp and the parchment formed at early development stage of pod. At 10 days after flowering(DAF) of parchmented pod pea, three to four strata of cells adjacent to endodermal cells were elongating and their walls were thickening, and then formed a tissue as palisade. At 13 DAF, the elongating cells had differentiated to form sclerenchyma membrane. During this process, the contents of cellulose and hemicellulose in pod increased significantly, while the content of lignin was still at a higher level which meant that the lignin was always synthesizing. But in the pod of edible pod pea, there were no morphological changes of cells in endocarp as parchmented pod pea and the content of cellulose and hemicellulose had no obvious increase while the content of lignin decreased significantly. Therefore, we deduce that the formation of parchment is originated from morphological changes of cells adjacent to endodermal and it not only closely relate to cell lignificantion, but aslo consiste of sclerenchym cells which had higher contents of cellulose and hemicellulose.Leaf-use pea is the type of pea that is used to produe tender tips of plants (pea shoots) as vagetable. Pea shoots are generally 5~15cm and include 2~4 pairs of leaves and immature tendrils. Today pea shoots are a popular specialty vegetable called"Wandoumiao"in Shanghai. The yield and harvest times can be decided by regrowth ability of variety, sowing date and environmental conditions. In order to decide the optimum sowing date of leaf-use pea in field, we sowed the same pea variety at different dates from November, 2006 to April,2007 and investigated yield and harvest times of pea shoots. The results showed that there were significant differences among different sowing dates. Pea sowed at first 3 stages(Nov.1st~Dec.1st) could be harvested 4~5 times, but the last 3 stages(sowed after Mar.15th) pea could not harvest pea shoots because high temperature made plant flower very early. The total yield of pea shoots indicated that pea sowed at 2~4 stages (Nov.15th~Dec.15th) which had good type had higher yield than that of other stages. So it can be concluded that pea sowed at November and December not only could produce more pea shoots, but also could be harvest several times. This period would be optimum sowing date for leaf-use pea in field at Shanghai.