不同基质配比对薄壳山核桃扦插苗成活率和光合作用的影响

为了提高薄壳山核桃硬枝扦插成活率,利用5种配比(基质1,泥炭;基质2,蛭石;基质3,泥炭:蛭石:珍珠岩=3:4:3;基质4,泥炭:蛭石:珍珠岩=3:5:2;基质5,泥炭:蛭石:珍珠岩=2:3:5)的薄壳山核桃基质探究其对薄壳山核桃2年生硬枝扦插成活率和扦插苗生长状况的影响。结果显示:(1)5种配比的山核桃基质中,成活率最好的是基质5,成活率达到88.9%,成活率最差的是基质1,只有63.3%,碱解氮与扦插苗成活率相关性最高。(2)5组美国山核桃扦插苗叶绿素含量最高的是基质1,到达5.0 mg·g-1,最差的是基质2,为3.26 mg·g-1,叶绿素与碱解氮含量呈显著正相关。(3)5组扦插苗的净光合速率随光合有效辐射升高而升高,最后趋于稳定,光抑制现象不明显;各组扦插苗最大净光合速率差异不显著。相比于6月份,9月叶片最大净光合速率有明显下降,蒸腾速率有所提高。研究认为,基质5为薄壳山核桃最适硬枝扦插基质,薄壳山核桃扦插苗生长过程中要注意土壤的透气性和氮肥的施用,薄壳山核桃扦插苗光合作用有季节性差异。

Effects of different substrates on the cutting survival rate and photosynthesis of Pecan

In order to improve the survival rate of hardwood cuttings of pecan, the effects of five substrates?on the survival rate of two-year-old hardwood cuttings of pecan and the growth was explored. Five cutting substrates were peat, vermiculite, peat: vermiculite: perlite of 3:4:3 (v/v/v), peat: vermiculite: perlite of 3:5:2 (v/v/v), and peat: vermiculite: perlite of 2:3:5 (v/v/v). The results were as follows. (1) The highest survival rate of pecan cuttings was 88.9% in the substrate of peat: vermiculite: perlite of 3:5:2, while only 63.3% of the survival rate was obtained in peat. Alkali-hydrolyzale nitrogen showed the highest correlation with the cutting survival rate. (2) The highest and lowest chlorophyll contents (5.0 and 3.26 mg·L^-1) were observed in pecan rooted cuttings in peat and vermiculate. The chlorophyll content was significantly related to alkaline-hydrolysis nitrogen. (3) The net photosynthetic?rate increased with an increase of the photosynthetic active radiation and gradually stabilized. The light-inhibition?phenomenon was not obvious. P_max was not significant different among the rooted cuttings in the five substrates. The net photosynthetic rate obviously decreased and the transpiration increased in September compared to that in June. The result suggested that the best substrate for pecan hardwood cutting is the substrate of peat: vermiculite: perlite of 3:5:2. Attentions should be paid to the soil permeability and nitrogen?fertilizer application during the growth period of pecan. The photosynthesis of rooted pecan cuttings changed in different growing seasons.