Winter stresses to crops and native plants during climate change Bjarni E. Guðleifsson Agricultural University of Iceland, Modruvellir, 601 Akureyri, Iceland INTRODUCTION Perennial plants are subject to many kinds of winter stresses. Plants are damaged or killed if the environmental stress passes the tolerance of the plant. The tolerance to winter stresses is much more studied in crops than in wild native plants. Crops are often introduced species or cultivars, not always adapted to the local climate. On the other hand iIndigenious plants are adapted to the local winter stresses and prevailing climate. The proportion of different stresses in damage to hayfields and trees in Iceland has been estimated. Ice damage dominates in herbage crops and frost in wooddy plants. Type of stress In Icelandi c hayfield s, % In Icelandi c forests, % Frost heaving 1 8 Drought 2 5 Frost 5 85 Energy starvation + ? Flooding + ? Ice encasement 90 - Snow molds 2 2 TOLERANCE TESTS Wild indigenious plants are distributed to localities where the stress intensity is lower than the plant tolerance to that particular stress. Preliminary test of a few alpine plant species, indicates that plants living in snow patches (e.g. Sibbaldia) possess fairly low frost tolerance, whereas plants living in dry location (e.g. Three- leaved rush) are tolerant to both frost and ice. Species Frost tolerance LT 50 , °C Ice toleranc e LD 50 , Days Winter wheat Triticum aestivum - 19 15 Timothy Phleum pratense -20 37 Sibbaldia Sibbaldia procumbens -11 35 Three-laved rush Juncus triﬁdus -20 49 IMPACT OF CLIMATE CHANGE Temperatures are expected to rise dramatically In futural climate change. During the next 50 years the mean temperature in Iceland is expected to rise 1,5 °C during summer and 3,0 °C during winter. Winter stresses to crops and plants at lower altitudes will decrease and winter damages might disappear. However, warm winter thaws might promote premature plant dehardening and growth, resulting in damages caused by subsequent stresses. The high rise in winter temperature will result in decreased snow cover at higher altitudes, and this might result in increase or change in winter stresses at higher altitudes. Plants adapted to snow mold stress might therefore in the future experience frost or ice encasement to which they are not well adapted. Therefore winter damages at higher altitudes might increase and influence distribution ABSTRACT The main winter stresses to plants are frost, ice encasement and low temperature parasitic fungi. In Iceland, ice cover mainly damages herbage crops whereas frost causes damage to woody plants. Wild alpine plants are better adapted to these winter stresses than crops, some are frost tolerant, others are ice tolerant, depending on their growing site. The expected increase in winter temperatures, caused by climate change, will reduce winter damages to crops cultivated at low altitudes. Decrease in snow cover at higher altitudes might on the other hand increase frost and ice cover stress to alpine plants which might be damaged. Year 2000 Year 2050 ICE ICE ICE ICE ICE FROST FROST FROST FROST FROST FUNGI FUNGI

Winter stresses to crops and native plants during climate change Bjarni E. Guðleifsson Agricultural University of Iceland, Modruvellir, 601 Akureyri, Iceland

Download PPT Report

View
218
Download
6

Tags:

Embed Size (px)

Citation preview

Winter stresses to crops and native plants during climate changeBjarni E. Guðleifsson

Agricultural University of Iceland, Modruvellir, 601 Akureyri, Iceland

INTRODUCTIONPerennial plants are subject to many kinds of winter stresses. Plants are damaged or killed if the environmental stress passes the tolerance of the plant. The tolerance to winter stresses is much more studied in crops than in wild native plants. Crops are often introduced species or cultivars, not always adapted to the local climate. On the other hand iIndigenious plants are adapted to the local winter stresses and prevailing climate. The proportion of different stresses in damage to hayfields and trees in Iceland has been estimated. Ice damage dominates in herbage crops and frost in wooddy plants.

Type of stress In Icelandic hayfields,

In Icelandic forests, %

Frost heaving 1 8

Drought 2 5

Frost 5 85

Energy starvation + ?

Flooding + ?

Ice encasement 90 -

Snow molds 2 2

TOLERANCE TESTSWild indigenious plants are distributed to localities where the stress intensity is lower than the plant tolerance to that particular stress. Preliminary test of a few alpine plant species, indicates that plants living in snow patches (e.g. Sibbaldia) possess fairly low frost tolerance, whereas plants living in dry location (e.g. Three-leaved rush) are tolerant to both frost and ice.

Species Frost tolerance

LT50,

°C

Ice tolerance

LD50,

Days

Winter wheat Triticum aestivum - 19 15

Timothy Phleum pratense -20 37

Sibbaldia Sibbaldia procumbens -11 35

Three-laved rush Juncus trifidus -20 49

IMPACT OF CLIMATE CHANGETemperatures are expected to rise dramatically In futural climate change. During the next 50 years the mean temperature in Iceland is expected to rise 1,5 °C during summer and 3,0 °C during winter. Winter stresses to crops and plants at lower altitudes will decrease and winter damages might disappear. However, warm winter thaws might promote premature plant dehardening and growth, resulting in damages caused by subsequent stresses. The high rise in winter temperature will result in decreased snow cover at higher altitudes, and this might result in increase or change in winter stresses at higher altitudes. Plants adapted to snow mold stress might therefore in the future experience frost or ice encasement to which they are not well adapted. Therefore winter damages at higher altitudes might increase and influence distribution of alpine plants.

ABSTRACTThe main winter stresses to plants are frost, ice encasement and low temperature parasitic fungi. In Iceland, ice cover mainly damages herbage crops whereas frost causes damage to woody plants. Wild alpine plants are better adapted to these winter stresses than crops, some are frost tolerant, others are ice tolerant, depending on their growing site. The expected increase in winter temperatures, caused by climate change, will reduce winter damages to crops cultivated at low altitudes. Decrease in snow cover at higher altitudes might on the other hand increase frost and ice cover stress to alpine plants which might be damaged.

Year 2000

Year 2050

ICE

T FR