Báo cáo lâm nghiệp: Effects of soil temperature on gas exchange and morphological structure of shoot and root in 1 yr old Scots pine (Pinus sylvestris L.) seedlings

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Effects of soil temperature on gas exchange and morphological structure of shoot and root in 1 yr old Scots pine (Pinus sylvestris L.) seedlings...
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Báo cáo lâm nghiệp: "Effects of soil temperature on gas exchange and morphological structure of shoot and root in 1 yr old Scots pine (Pinus sylvestris L.) seedlings"Effects of soil temperature on gas exchange and mor-phological structure of shoot and root in 1 yr old Scotspine (Pinus sylvestris L.) seedlings P. PuttonenJ. Lippu Unioninkatu 40 B, 00170 Helsinki, FinlandDepartment of Silviculture, University of Helsinki,Introduction Materials and Methods One yr old Scots pine seedlings growing 30 d atLow soil temperature is one of the envi- 13°C, 18 h photoperiod, 250 pmol-m- ir- 1 -s- 2ronmental factors affecting early growth radiance and 7 mbar vapor pressure deficit in aand survival of forest seedlings in boreal mixture of low humified Sphagnum peat andecosystems. With regard to gas exchange perlite were exposed to 3 different soil tempera-and growth, soil temperature is often ture treatments (8°C, 12°C and a changing tem- perature from 5.5 to 13.0°C). Soil temperatureunderoptimal in spring and early summer was controlled by immersing sealed pots into a(S6derstr6m, 1974). water bath thermostated by a Lauda RS-102 thermostat. Net C0 assimilation (A), transpira- In cold soils, the viscosity of water 2 tion (E) and leaf conductance to water vaporincreases and the permeability of roots to measured LI-6200 by portable pho- (g) were anwater decreases (Lopushinsky and Kauf- Inc.), which tosynthesis system (LI-COR,mann, 1977) which leads to decreased includes an LI-6250 infrared gas analyzer, angas exchange and growth. LI-6200 control console and a leaf chamber. The relative height growth rate (RHGR) was The aim of this study was to examine 1 /H x calculated using the equation: RNGR =certain structural and physiological attri- dH/dt An index of photosynthetic efficiencybutes of acclimation in Scots pine (Pinus (PE) or photosynthetic utilization of internal C0 2sylvestris L.) seedlings at different soil was derived by dividing the rate of net photo- synthesis by the internal C0 concentration 2temperatures. (Sasek et al., 1985). The following structural factors wereexamined: 1) timing and amount of shootgrowth; 2) amount of needle and root Resultsgrowth. The following physiological factors wereexamined: 1) net C0 assimilation rate 2 The patterns of A at 2 constant soil tem-(A); 2) transpiration (E); and 3) conduc- peratures (12.0 and 8.7°C) were quitetance to water vapor (g). similar but at 12°C the photosynthetic rate quite simi- soil temperature higher (Fig. 1However, after 11 d, changing werewas throughout the experiment but the for-differences lar were no longer significant. ...