| The research was conducted with 5-year-old nectarine Shuguang(Prunus Persica Var. nectarina Maxim. Shuguang / Pruns Davidiana Carr. Franch) and Zaohongzhu(Prunus Persica Var. nectarina Maxim. Zaohongzhu / Pruns Davidiana Carr. Franch) in greenhouse in the garden of horticultural department, Shandong Agricultural University between the year 2002 to 2003. The rules of growth and development of roots, relativity between roots growth and the top growth, physiological and biochemical metabolism of roots and partial root-zone irrigation were studied. The results are as follows:There are two growing peaks of new roots in a year. One occurred between Feb to Apr, when the monthly average soil temperature was in 12℃ to 15℃, and the new roots quantity was so excessively that it can account for about 70 percent of the total roots in a year. Another occurred from Jul to Aug, and the soil temperature in this period is the highest in a year. However, the growth quantity of the second peak is far less than the first one. New roots of different soil layers grow alternatively, and no matter what varieties it is, the number peak occurs simultaneously with the length peak. Being intense competition among root growth, new shoots and fruit growth, they contest storing nutrition in prophase and photosynthesis matter in anaphase. The new shoots and the new roots grow by turns. In prophase, the fruits growth compete nutrition with the new roots and the new shoots, but it mainly compete with the new shoots in anaphase. The results show that in the period of new roots growth the changes of the sugar, protein, amino acid content and the POD and SOD activity in roots have the similar rhythm with the new roots growth, while the starch content is contrary. The content of starch, sugar, and POD activity in thick roots are higher than thin roots, however the content of protein, amino acid and SOD activity change irregularly. In the process of roots growing annually, the content of roots starch accumulate in the slow growth period, and decrease in the period of roots growth peak. The content of soluble sugar, protein and amino acid all increase in the period of new roots growth peak, then decrease after the peaking period. The content of soluble sugar and amino acid increase in slow growth period, but the content of protein decreases.The results showed that APRI and FPRI inhibited new shoots growth and caused pre-maturity. Average fruits weight and fruits rigidity obtained in APRI and FPRI treatments were reduced, but not yield, and the total soluble solids (T.S.S.) were increased. Water saving of 50% was achieved in APRI and FPRI, and water use efficiency (WUE) was increased. Compared with APRI, average fruits weight, yield, total soluble solids (T.S.S.) and water using efficiency (WUE) of FPRI were all increased, except of fruit rigidity.The order of net photosynthetic rate, transpiration rate and the instant water use efficiency of leaves from high to low are: FPRI, CI, APRI; CI, APRI, FPRI; FPRI, APRI, CI; respectively. The stomatic conductance of leaves of APRI is basically as same as FPRI, but both are less than CI. The content of starch, soluble sugar, amino acid, chlorophyll a, chlorophyll b and carotenoid of leaves of both APRI and FPRI are less than CI, but the content of proline and carotenoid and the activity of SOD and POD are higher than CI. The content of starch, soluble sugar, proline, chlorophyll a, chlorophyll b, carotenoid and POD activity of leaves of APRI are higher than FPRI, while the total content of amino acid and SOD activity are less than FPRI.
|
PDF Full Text Request